Showing papers by "Katie M. Morzinski published in 2015"
Lawrence Livermore National Laboratory1, Stanford University2, University of California, Berkeley3, University of Arizona4, University of California, San Diego5, Ames Research Center6, University of Victoria7, Herzberg Institute of Astrophysics8, Space Telescope Science Institute9, Arizona State University10, Université de Montréal11, Los Alamos National Laboratory12, University of California, Los Angeles13, University of Western Ontario14, Subaru15, University of Hertfordshire16, Princeton University17, University of Toronto18, Centre national de la recherche scientifique19, University of Chicago20, University of California, Santa Cruz21, Durham University22, University of Exeter23, University of Georgia24, Stony Brook University25, University of California, Santa Barbara26, American Museum of Natural History27, University of Chile28, Universities Space Research Association29, Cornell University30, University of Toledo31, California Institute of Technology32
TL;DR: Using the Gemini Planet Imager, a Jupiter-like planet is discovered orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units and has a methane signature and is probably the smallest exoplanet that has been directly imaged.
Abstract: Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter.
575 citations
Lawrence Livermore National Laboratory1, Stanford University2, University of California, Berkeley3, University of Arizona4, University of California, San Diego5, Ames Research Center6, University of Victoria7, Herzberg Institute of Astrophysics8, Space Telescope Science Institute9, Arizona State University10, Université de Montréal11, Los Alamos National Laboratory12, University of California, Los Angeles13, University of Western Ontario14, Subaru15, University of Hertfordshire16, Princeton University17, University of Toronto18, Centre national de la recherche scientifique19, University of Chicago20, University of California, Santa Cruz21, Durham University22, University of Exeter23, University of Georgia24, Stony Brook University25, University of California, Santa Barbara26, American Museum of Natural History27, University of Chile28, Universities Space Research Association29, Cornell University30, University of Toledo31, California Institute of Technology32
TL;DR: In this paper, the Gemini Planet Imager was used to detect a planet orbiting the star 51 Eridani at a projected separation of 13 astronomical units, with a spectrum with strong methane and water vapor absorption.
Abstract: Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric composition and luminosity, which is influenced by their formation mechanism. Using the Gemini Planet Imager, we discovered a planet orbiting the \$sim$20 Myr-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water vapor absorption. Modeling of the spectra and photometry yields a luminosity of L/LS=1.6-4.0 x 10-6 and an effective temperature of 600-750 K. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold- start" core accretion process that may have formed Jupiter.
375 citations
TL;DR: In this paper, adaptive optics observations of LkCa 15 that probe within the disk clearing are reported, with accurate source positions over multiple epochs spanning 2009-2015, infer the presence of multiple companions on Keplerian orbits.
Abstract: Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1,900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition disks, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition disks show evidence for the presence of young planets in the form of disk asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15 (refs 8, 9). Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disk clearing. With accurate source positions over multiple epochs spanning 2009-2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect Hα emission from the innermost companion, LkCa 15 b, evincing hot (about 10,000 kelvin) gas falling deep into the potential well of an accreting protoplanet.
356 citations
Space Telescope Science Institute1, Centre national de la recherche scientifique2, University of Grenoble3, University of California, Berkeley4, University of Toronto5, University of California, Los Angeles6, University of California, Santa Cruz7, Stanford University8, Lawrence Livermore National Laboratory9, University of Exeter10, Arizona State University11, Université de Montréal12, National Research Council13, Search for extraterrestrial intelligence14, University of Arizona15, American Museum of Natural History16, Cornell University17, University of Georgia18, Ames Research Center19, California Institute of Technology20, Johns Hopkins University21
TL;DR: In this paper, the first results from the polarimetry mode of the Gemini Planet Imager (GPI) were presented, showing that the disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side 9 times brighter than the east side despite the fact that the east sides are slightly brighter in total intensity.
Abstract: We present the first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI's advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side 9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's F ring.
182 citations
TL;DR: In this article, the authors used a dust density model combined with a Henyey-Greenstein scattering phase function to fit a disk inclined to the line of sight with a position angle of 30.35°.
Abstract: We present $H$-band observations of $\beta$ Pic with the Gemini Planet Imager's (GPI's) polarimetry mode that reveal the debris disk between ~0.3" (~6 AU) and ~1.7" (~33 AU), while simultaneously detecting $\beta$ Pic $b$. The polarized disk image was fit with a dust density model combined with a Henyey-Greenstein scattering phase function. The best fit model indicates a disk inclined to the line of sight ($\phi=85.27°^{+0.26}_{-0.19}$) with a position angle $\theta_{PA}=30.35°^{+0.29}_{-0.28}$ (slightly offset from the main outer disk, $\theta_{PA}\approx29°$), that extends from an inner disk radius of $23.6^{+0.9}_{-0.6}$ AU to well outside GPI's field of view. In addition, we present an updated orbit for $\beta$ Pic $b$ based on new astrometric measurements taken in GPI's spectroscopic mode spanning 14 months. The planet has a semi-major axis of $a=9.2^{+1.5}_{-0.4}$AU, with an eccentricity $e\leq 0.26$. The position angle of the ascending node is $\Omega=31.75°\pm0.15$, offset from both the outer main disk and the inner disk seen in the GPI image. The orbital fit constrains the stellar mass of $\beta$ Pic to $1.60\pm0.05 M_{\odot}$. Dynamical sculpting by $\beta$ Pic $b$ cannot easily account for the following three aspects of the inferred disk properties: 1) the modeled inner radius of the disk is farther out than expected if caused by $\beta$ Pic b; 2) the mutual inclination of the inner disk and $\beta$ Pic $b$ is $4°$, when it is expected to be closer to zero; and 3) the aspect ratio of the disk ($h_0 = 0.137^{+0.005}_{-0.006}$) is larger than expected from interactions with $\beta$ Pic $b$ or self-stirring by the disk's parent bodies.
126 citations
University of Toronto1, University of California, Berkeley2, Space Telescope Science Institute3, Stanford University4, Lawrence Livermore National Laboratory5, University of Arizona6, University of Georgia7, National Research Council8, University of Victoria9, University of Grenoble10, University of California, Los Angeles11, Johns Hopkins University12, University of Exeter13, California Institute of Technology14, University of California, San Diego15, Search for extraterrestrial intelligence16, Ames Research Center17, American Museum of Natural History18, Arizona State University19, Universities Space Research Association20, University of Toledo21, California State Polytechnic University, Pomona22, University of California, Santa Cruz23
TL;DR: In this paper, the authors presented an H-band observations of β Pic with the Gemini Planet Imager's (GPI's) polarimetry mode that reveal the debris disk between ∼0.″3 (6 AU) and ∼1.″7 (33 AU) while simultaneously detecting β Pic b.
Abstract: Author(s): Millar-Blanchaer, MA; Graham, JR; Pueyo, L; Kalas, P; Dawson, RI; Wang, J; Perrin, MD; Moon, DS; Macintosh, B; Ammons, SM; Barman, T; Cardwell, A; Chen, CH; Chiang, E; Chilcote, J; Cotten, T; Rosa, RJD; Draper, ZH; Dunn, J; Duchene, G; Esposito, TM; Fitzgerald, MP; Follette, KB; Goodsell, SJ; Greenbaum, AZ; Hartung, M; Hibon, P; Hinkley, S; Ingraham, P; Jensen-Clem, R; Konopacky, Q; Larkin, JE; Long, D; Maire, J; Marchis, F; Marley, MS; Marois, C; Morzinski, KM; Nielsen, EL; Palmer, DW; Oppenheimer, R; Poyneer, L; Rajan, A; Rantakyro, FT; Ruffio, JB; Sadakuni, N; Saddlemyer, L; Schneider, AC; Sivaramakrishnan, A; Soummer, R; Thomas, S; Vasisht, G; Vega, D; Wallace, JK; Ward-Duong, K; Wiktorowicz, SJ; Wolff, SG | Abstract: We present H-band observations of β Pic with the Gemini Planet Imager's (GPI's) polarimetry mode that reveal the debris disk between ∼0.″3 (6 AU) and ∼1.″7 (33 AU), while simultaneously detecting β Pic b. The polarized disk image was fit with a dust density model combined with a Henyey-Greenstein scattering phase function. The best-fit model indicates a disk inclined to the line of sight () with a position angle (PA) (slightly offset from the main outer disk, ), that extends from an inner disk radius of to well outside GPI's field of view. In addition, we present an updated orbit for β Pic b based on new astrometric measurements taken in GPI's spectroscopic mode spanning 14 months. The planet has a semimajor axis of , with an eccentricity The PA of the ascending node is offset from both the outer main disk and the inner disk seen in the GPI image. The orbital fit constrains the stellar mass of β Pic to Dynamical sculpting by β Pic b cannot easily account for the following three aspects of the inferred disk properties: (1) the modeled inner radius of the disk is farther out than expected if caused by β Pic b; (2) the mutual inclination of the inner disk and β Pic b is when it is expected to be closer to zero; and (3) the aspect ratio of the disk () is larger than expected from interactions with β Pic b or self-stirring by the disk's parent bodies.
115 citations
TL;DR: The Magellan and Las Campanas Observatory staff made this well-engineered, smoothly operated telescope and site possible as mentioned in this paper, and they would especially like to thank Povilas Palunas for help over the entire MagAO commissioning run.
Abstract: We thank the Magellan and Las Campanas Observatory staff for making this well-engineered, smoothly operated telescope and site possible. We would especially like to thank Povilas Palunas for help over the entire MagAO commissioning run. Juan Gallardo, Patricio Jones, Emilio Cerda, Felipe Sanchez, Gabriel Martin, Maurico Navarrete, Jorge Bravo, Victor Merino, Patricio Pinto, Gabriel Prieto, Mauricio Martinez, Alberto Pasten, Jorge Araya, Hugo Rivera, and the whole team of technical experts helped perform many exacting tasks in a very professional manner. Glenn Eychaner, David Osip, and Frank Perez all gave expert support which was fantastic. The entire logistics, dining, housekeeping, and hospitality staff provide for an excellent, healthy environment that ensured the wellness of our team throughout the commissioning runs. It is a privilege to be able to commission an AO system with such a fine staff and site. The MagAO system was developed with support from the NSF, MRI and TSIP programs. The VisAO camera was developed with help from the NSF ATI program. K.M.M. and J.R.M. were supported under contract with the California Institute of Technology, funded by NASA through the Sagan Fellowship Program. J.R.M. is grateful for the generous support of the Phoenix ARCS Foundation. L.M.C.'s and Y.-L.W.'s research were supported by NSF AAG and NASA Origins of Solar Systems grants. V.B. was supported in part by the NSF Graduate Research Fellowship Program (DGE-1143953). We thank the anonymous referee for a careful, timely review that significantly improved the manuscript. Facility: Magellan:Clay (MagAO+Clio) .
108 citations
TL;DR: In this article, the spectral energy distribution (SED) of a young giant exoplanet was measured empirically and the luminosity of the planet was calculated using a blackbody.
Abstract: Young giant exoplanets are a unique laboratory for understanding cool, low-gravity atmospheres. A quintessential example is the massive extrasolar planet $\beta$ Pic b, which is 9 AU from and embedded in the debris disk of the young nearby A6V star $\beta$ Pictoris. We observed the system with first light of the Magellan Adaptive Optics (MagAO) system. In Paper I we presented the first CCD detection of this planet with MagAO+VisAO. Here we present four MagAO+Clio images of $\beta$ Pic b at 3.1 $\mu$m, 3.3 $\mu$m, $L^\prime$, and $M^\prime$, including the first observation in the fundamental CH$_4$ band. To remove systematic errors from the spectral energy distribution (SED), we re-calibrate the literature photometry and combine it with our own data, for a total of 22 independent measurements at 16 passbands from 0.99--4.8 $\mu$m. Atmosphere models demonstrate the planet is cloudy but are degenerate in effective temperature and radius. The measured SED now covers $>$80\% of the planet's energy, so we approach the bolometric luminosity empirically. We calculate the luminosity by extending the measured SED with a blackbody and integrating to find log($L_{bol}$/$L_{Sun}$) $= -3.78\pm0.03$. From our bolometric luminosity and an age of 23$\pm$3 Myr, hot-start evolutionary tracks give a mass of 12.7$\pm$0.3 $M_{Jup}$, radius of 1.45$\pm$0.02 $R_{Jup}$, and $T_{eff}$ of 1708$\pm$23 K (model-dependent errors not included). Our empirically-determined luminosity is in agreement with values from atmospheric models (typically $-3.8$ dex), but brighter than values from the field-dwarf bolometric correction (typically $-3.9$ dex), illustrating the limitations in comparing young exoplanets to old brown dwarfs.
108 citations
University of California, Berkeley1, Arizona State University2, University of Toronto3, University of Grenoble4, Centre national de la recherche scientifique5, Space Telescope Science Institute6, University of California, Los Angeles7, Stanford University8, University of California, Santa Barbara9, National Research Council10, Université de Montréal11, Lawrence Livermore National Laboratory12, Subaru13, University of Georgia14, Johns Hopkins University15, University of Exeter16, University of California, San Diego17, Search for extraterrestrial intelligence18, Stony Brook University19, University of Western Ontario20, University of Arizona21, American Museum of Natural History22, Cornell University23, University of Toledo24, California Institute of Technology25, University of California, Santa Cruz26
TL;DR: Kalas et al. as discussed by the authors presented the first scattered light detections of the HD 106906 debris disk using the Gemini/Gemini Planet Imager in the infrared and Hubble Space Telescope (HST)/Advanced Camera for Surveys in the optical.
Abstract: Author(s): Kalas, PG; Rajan, A; Wang, JJ; Millar-Blanchaer, MA; Duchene, G; Chen, C; Fitzgerald, MP; Dong, R; Graham, JR; Patience, J; Macintosh, B; Murray-Clay, R; Matthews, B; Rameau, J; Marois, C; Chilcote, J; Rosa, RJD; Doyon, R; Draper, ZH; Lawler, S; Ammons, SM; Arriaga, P; Bulger, J; Cotten, T; Follette, KB; Goodsell, S; Greenbaum, A; Hibon, P; Hinkley, S; Hung, LW; Ingraham, P; Konapacky, Q; Lafreniere, D; Larkin, JE; Long, D; Maire, J; Marchis, F; Metchev, S; Morzinski, KM; Nielsen, EL; Oppenheimer, R; Perrin, MD; Pueyo, L; Rantakyro, FT; Ruffio, JB; Saddlemyer, L; Savransky, D; Schneider, AC; Sivaramakrishnan, A; Soummer, R; Song, I; Thomas, S; Vasisht, G; Ward-Duong, K; Wiktorowicz, SJ; Wolff, SG | Abstract: We present the first scattered light detections of the HD 106906 debris disk using the Gemini/Gemini Planet Imager in the infrared and Hubble Space Telescope (HST)/Advanced Camera for Surveys in the optical. HD 106906 is a 13 Myr old F5V star in the Sco-Cen association, with a previously detected planet-mass candidate HD 106906b projected 650 AU from the host star. Our observations reveal a near edge-on debris disk that has a central cleared region with radius ∼50 AU, and an outer extent g500 AU. The HST data show that the outer regions are highly asymmetric, resembling the "needle" morphology seen for the HD 15115 debris disk. The planet candidate is oriented ∼21° away from the position angle of the primary's debris disk, strongly suggesting non-coplanarity with the system. We hypothesize that HD 106906b could be dynamically involved in the perturbation of the primary's disk, and investigate whether or not there is evidence for a circumplanetary dust disk or cloud that is either primordial or captured from the primary. We show that both the existing optical properties and near-infrared colors of HD 106906b are weakly consistent with this possibility, motivating future work to test for the observational signatures of dust surrounding the planet.
97 citations
University of Arizona1, University of Padua2, University of Virginia3, University of Edinburgh4, Max Planck Society5, University of Grenoble6, University of Notre Dame7, University of Exeter8, Arizona State University9, University of California, Santa Cruz10, Ames Research Center11, University of Minnesota12
TL;DR: In this paper, the authors derived new astrometry, test the predictions of the orbital model of 8:4:2:1 mean motion resonance proposed for the system, and perform new orbital fitting of the HR 8799 bcde planets.
Abstract: Context. Astrometric monitoring of directly imaged exoplanets allows the study of their orbital parameters and system architectures. Because most directly imaged planets have long orbital periods (>20 AU), accurate astrometry is challenging when based on data acquired on timescales of a few years and usually with different instruments. The LMIRCam camera on the Large Binocular Telescope is being used for the LBT Exozodi Exoplanet Common Hunt (LEECH) survey to search for and characterize young and adolescent exoplanets in L ′ band (3.8 μ m), including their system architectures.Aims. We first aim to provide a good astrometric calibration of LMIRCam. Then, we derive new astrometry, test the predictions of the orbital model of 8:4:2:1 mean motion resonance proposed for the system, and perform new orbital fitting of the HR 8799 bcde planets. We also present deep limits on a putative fifth planet inside the known planets.Methods. We use observations of HR 8799 and the Θ1 Ori C field obtained during the same run in October 2013.Results. We first characterize the distortion of LMIRCam. We determine a platescale and a true north orientation for the images of 10.707 ± 0.012 mas/pix and −0.430 ± 0.076°, respectively. The errors on the platescale and true north orientation translate into astrometric accuracies at a separation of 1′′ of 1.1 mas and 1.3 mas, respectively. The measurements for all planets agree within 3σ with a predicted ephemeris. The orbital fitting based on the new astrometric measurements favors an architecture for the planetary system based on 8:4:2:1 mean motion resonance. The detection limits allow us to exclude a fifth planet slightly brighter or more massive than HR 8799 b at the location of the 2:1 resonance with HR 8799 e (~9.5 AU) and about twice as bright as HR 8799 cde at the location of the 3:1 resonance with HR 8799 e (~7.5 AU).
65 citations
University of California, Berkeley1, Search for extraterrestrial intelligence2, Stanford University3, Brown University4, University of California, San Diego5, National Research Council6, University of Victoria7, Space Telescope Science Institute8, Université de Montréal9, University of Chicago10, Lawrence Livermore National Laboratory11, University of California, Los Angeles12, University of Toronto13, University of Georgia14, University of Grenoble15, Durham University16, Johns Hopkins University17, University of Western Ontario18, Stony Brook University19, University of Arizona20, American Museum of Natural History21, Arizona State University22, University of Toledo23, California Institute of Technology24
TL;DR: De Rosa et al. as discussed by the authors presented new Gemini Planet Imager observations of the young exoplanet 51 Eridani b that provide further evidence that the companion is physically associated with the planet.
Abstract: Author(s): De Rosa, RJD; Nielsen, EL; Blunt, SC; Graham, JR; Konopacky, QM; Marois, C; Pueyo, L; Rameau, J; Ryan, DM; Wang, JJ; Bailey, V; Chontos, A; Fabrycky, DC; Follette, KB; MacIntosh, B; Marchis, F; Ammons, SM; Arriaga, P; Chilcote, JK; Cotten, TH; Doyon, R; Duchene, G; Esposito, TM; Fitzgerald, MP; Gerard, B; Goodsell, SJ; Greenbaum, AZ; Hibon, P; Ingraham, P; Johnson-Groh, M; Kalas, PG; Lafreniere, D; Maire, J; Metchev, S; Millar-Blanchaer, MA; Morzinski, KM; Oppenheimer, R; Patel, RI; Patience, JL; Perrin, MD; Rajan, A; Rantakyro, FT; Ruffio, JB; Schneider, AC; Sivaramakrishnan, A; Song, I; Tran, D; Vasisht, G; Ward-Duong, K; Wolff, SG | Abstract: We present new Gemini Planet Imager observations of the young exoplanet 51 Eridani b that provide further evidence that the companion is physically associated with 51 Eridani. Combining this new astrometric measurement with those reported in the literature, we significantly reduce the posterior probability that 51 Eridani b is an unbound foreground or background T-dwarf in a chance alignment with 51 Eridani to 2 × 10-7, an order of magnitude lower than previously reported. If 51 Eridani b is indeed a bound object, then we have detected orbital motion of the planet between the discovery epoch and the latest epoch. By implementing a computationally efficient Monte Carlo technique, preliminary constraints are placed on the orbital parameters of the system. The current set of astrometric measurements suggest an orbital semimajor axis of AU, corresponding to a period of years (assuming a mass of 1.75 Mo for the central star), and an inclination of deg. The remaining orbital elements are only marginally constrained by the current measurements. These preliminary values suggest an orbit that does not share the same inclination as the orbit of the distant M-dwarf binary, GJ 3305, which is a wide physically bound companion to 51 Eridani.
TL;DR: In this paper, Kuzuhara et al. observed GJ 504 b in three narrow L-band filters (3.71, 3.88, and 4.00 microns), spanning the red end of the broad methane fundamental absorption feature.
Abstract: As gas giant planets and brown dwarfs radiate away the residual heat from their formation, they cool through a spectral type transition from L to T, which encompasses the dissipation of cloud opacity and the appearance of strong methane absorption. While there are hundreds of known T-type brown dwarfs, the first generation of directly-imaged exoplanets were all L-type. Recently, Kuzuhara et al. (2013) announced the discovery of GJ 504 b, the first T dwarf exoplanet. GJ 504 b provides a unique opportunity to study the atmosphere of a new type of exoplanet with a ~500 K temperature that bridges the gap between the first directly imaged planets (~1000 K) and our own Solar System's Jupiter (~130 K). We observed GJ 504 b in three narrow L-band filters (3.71, 3.88, and 4.00 microns), spanning the red end of the broad methane fundamental absorption feature (3.3 microns) as part of the LEECH exoplanet imaging survey. By comparing our new photometry and literature photometry to a grid of custom model atmospheres, we were able to fit GJ 504 b's unusual spectral energy distribution for the first time. We find that GJ 504 b is well-fit by models with the following parameters: T_eff=544+/-10 K, g<600 m/s^2, [M/H]=0.60+/-0.12, cloud opacity parameter of f_sed=2-5, R=0.96+/-0.07 R_Jup, and log(L)=-6.13+/-0.03 L_Sun, implying a hot start mass of 3-30 M_jup for a conservative age range of 0.1-6.5 Gyr. Of particular interest, our model fits suggest that GJ 504 b has a super-stellar metallicity. Since planet formation can create objects with non-stellar metallicities, while binary star formation cannot, this result suggests that GJ 504 b formed like a planet, not like a binary companion.
Posted Content•
University of California, Berkeley1, Arizona State University2, University of Toronto3, University of Grenoble4, Centre national de la recherche scientifique5, Space Telescope Science Institute6, University of California, Los Angeles7, Stanford University8, University of California, Santa Barbara9, National Research Council10, Université de Montréal11, Lawrence Livermore National Laboratory12, Subaru13, University of Georgia14, Johns Hopkins University15, University of Exeter16, University of California, San Diego17, Search for extraterrestrial intelligence18, Stony Brook University19, University of Western Ontario20, University of Arizona21, American Museum of Natural History22, Cornell University23, University of Toledo24, California Institute of Technology25, University of California, Santa Cruz26
TL;DR: In this article, the authors presented the first scattered light detections of the HD 106906 debris disk using Gemini/GPI in the infrared and HST/ACS in the optical.
Abstract: We present the first scattered light detections of the HD 106906 debris disk using Gemini/GPI in the infrared and HST/ACS in the optical. HD 106906 is a 13 Myr old F5V star in the Sco-Cen association, with a previously detected planet-mass candidate HD 106906b projected 650 AU from the host star. Our observations reveal a near edge-on debris disk that has a central cleared region with radius $\sim$50 AU, and an outer extent $>$500 AU. The HST data show the outer regions are highly asymmetric, resembling the ''needle'' morphology seen for the HD 15115 debris disk. The planet candidate is oriented $\sim$21$\deg$ away from the position angle of the primary's debris disk, strongly suggesting non-coplanarity with the system. We hypothesize that HD 106906b could be dynamically involved in the perturbation of the primary's disk, and investigate whether or not there is evidence for a circumplanetary dust disk or cloud that is either primordial or captured from the primary. We show that both the existing optical properties and near-infrared colors of HD 106906b are weakly consistent with this possibility, motivating future work to test for the observational signatures of dust surrounding the planet.
University of California, Berkeley1, Search for extraterrestrial intelligence2, Stanford University3, Brown University4, University of California, San Diego5, National Research Council6, University of Victoria7, Space Telescope Science Institute8, Université de Montréal9, University of Chicago10, Lawrence Livermore National Laboratory11, University of California, Los Angeles12, University of Toronto13, University of Georgia14, University of Grenoble15, Durham University16, Johns Hopkins University17, University of Western Ontario18, Stony Brook University19, University of Arizona20, American Museum of Natural History21, Arizona State University22, University of Toledo23, California Institute of Technology24
TL;DR: In this article, the authors presented new Gemini Planet Imager observations of the young exoplanet 51 Eridani b which provide further evidence that the companion is physically associated with the planet.
Abstract: We present new Gemini Planet Imager observations of the young exoplanet 51 Eridani b which provide further evidence that the companion is physically associated with 51 Eridani. Combining this new astrometric measurement with those reported in the literature, we significantly reduce the posterior probability that 51 Eridani b is an unbound foreground or background T-dwarf in a chance alignment with 51 Eridani to $2\times10^{-7}$, an order of magnitude lower than previously reported. If 51 Eridani b is indeed a bound object, then we have detected orbital motion of the planet between the discovery epoch and the latest epoch. By implementing a computationally efficient Monte Carlo technique, preliminary constraints are placed on the orbital parameters of the system. The current set of astrometric measurements suggest an orbital semimajor axis of $14^{+7}_{-3}$ AU, corresponding to a period of $41^{+35}_{-12}$ years (assuming a mass of $1.75$ $M_{\odot}$ for the central star), and an inclination of $138^{+15}_{-13}$ deg. The remaining orbital elements are only marginally constrained by the current measurements. These preliminary values suggest an orbit which does not share the same inclination as the orbit of the distant M-dwarf binary, GJ 3305, which is a wide physically bound companion to 51 Eridani.
TL;DR: In this paper, non-redundant masking observations of the T Cha transition disk, taken at the Very Large Telescope and Magellan in the H, Ks, and L' bands, are presented.
Abstract: We present multi-epoch non-redundant masking observations of the T Cha transition disk, taken at the Very Large Telescope and Magellan in the H, Ks, and L' bands. T Cha is one of a small number of transition disks that host companion candidates discovered by high-resolution imaging techniques, with a putative companion at a position angle of 78?, separation of 62 mas, and contrast of ?L' = 5.1 mag. We find comparable binary parameters in our re-reduction of the initial detection images, and similar parameters in the 2011 L', 2013 NaCo L', and 2013 NaCo Ks data sets. We find a close-in companion signal in the 2012 NaCo L' data set that cannot be explained by orbital motion, and a non-detection in the 2013 MagAO/Clio2 L' data. However, Monte Carlo simulations show that the best fits to the 2012 NaCo and 2013 MagAO/Clio2 followup data may be consistent with noise. There is also a significant probability of false non-detections in both of these data sets. We discuss physical scenarios that could cause the best fits, and argue that previous companion and scattering explanations are inconsistent with the results of the much larger data set presented here.
TL;DR: In this article, the Magellan adaptive optics system and its VisAO CCD camera were used to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths.
Abstract: We used the Magellan adaptive optics system and its VisAO CCD camera to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths. We detect it at r', i', z', and YS . With our new photometry and T eff ~ 2500 K derived from the shape of its K-band spectrum, we find that CT Cha B has AV = 3.4 ± 1.1 mag, and a mass of 14-24 MJ according to the DUSTY evolutionary tracks and its 1-5 Myr age. The overluminosity of our r' detection indicates that the companion has significant Hα emission and a mass accretion rate ~6 × 10–10 M ☉ yr–1, similar to some substellar companions. Proper motion analysis shows that another point source within 2'' of CT Cha A is not physical. This paper demonstrates how visible wavelength adaptive optics photometry (r', i', z', YS ) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions.
University of California, Berkeley1, Space Telescope Science Institute2, Search for extraterrestrial intelligence3, Stanford University4, University of Toronto5, Lawrence Livermore National Laboratory6, Arizona State University7, Université de Montréal8, National Research Council9, University of Victoria10, University of Grenoble11, University of California, Los Angeles12, Durham University13, Johns Hopkins University14, University of Exeter15, University of Arizona16, American Museum of Natural History17, University of California, Santa Cruz18
TL;DR: Wang et al. as mentioned in this paper used the Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk.
Abstract: Author(s): Wang, JJ; Graham, JR; Pueyo, L; Nielsen, EL; Millar-Blanchaer, M; Rosa, RJD; Kalas, P; Ammons, SM; Bulger, J; Cardwell, A; Chen, C; Chiang, E; Chilcote, JK; Doyon, R; Draper, ZH; Duchene, G; Esposito, TM; Fitzgerald, MP; Goodsell, SJ; Greenbaum, AZ; Hartung, M; Hibon, P; Hinkley, S; Hung, LW; Ingraham, P; Larkin, JE; Macintosh, B; Maire, J; Marchis, F; Marois, C; Matthews, BC; Morzinski, KM; Oppenheimer, R; Patience, J; Perrin, MD; Rajan, A; Rantakyro, FT; Sadakuni, N; Serio, A; Sivaramakrishnan, A; Soummer, R; Thomas, S; Ward-Duong, K; Wiktorowicz, SJ; Wolff, SG | Abstract: We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1″ (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side at similar separations. This part of the disk is also vertically offset by 69 ± 30 mas to the northeast at 1″ when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction ∼50 mas between 0.″4 and 1.″2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for ∼4 MJup planets at 4 AU. We detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.
TL;DR: In this paper, the Magellan adaptive optics system was used to image the 11 Myr substellar companion 1RXS 1609 B at the bluest wavelengths to date (z' and Ys).
Abstract: We used the Magellan adaptive optics system to image the 11 Myr substellar companion 1RXS 1609 B at the bluest wavelengths to date (z' and Ys). Comparison with synthetic spectra yields a higher temperature than previous studies of and significant dust extinction of mag. Mass estimates based on the DUSTY tracks gives 0.012–0.015 , making the companion likely a low-mass brown dwarf surrounded by a dusty disk. Our study suggests that 1RXS 1609 B is one of the ~25% of Upper Scorpius low-mass members harboring disks, and it may have formed like a star and not a planet out at ~320 AU.
TL;DR: In this article, the authors show that binary differential imaging (BDI) offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star, where two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at high Strehl ratio.
Abstract: Binaries are typically excluded from direct imaging exoplanet surveys. However, the recent findings of Kepler and radial velocity programs show that planets can and do form in binary systems. Here, we suggest that visual binaries offer unique advantages for direct imaging. We show that Binary Differential Imaging (BDI), whereby two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at high Strehl ratio, offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star. We demonstrate this by observing a young visual binary separated by 4\asec ~with MagAO/Clio-2 at 3.9 \microns, where the Strehl ratio is high, the isoplanatic patch is large, and giant planets are bright. Comparing BDI to angular differential imaging (ADI), we find that BDI's 5$\sigma$ contrast is \about 0.5 mags better than ADI's within \about 1\asec ~for the particular binary we observed. Because planets typically reside close to their host stars, BDI is a promising technique for discovering exoplanets in stellar systems that are often ignored. BDI is also 2-4$\times$ more efficient than ADI and classical reference PSF subtraction, since planets can be detected around both the target and PSF reference simultaneously. We are currently exploiting this technique in a new MagAO survey for giant planets in 140 young nearby visual binaries. BDI on a space-based telescope would not be limited by isoplanatism effects and would therefore be an even more powerful tool for imaging and discovering planets.
TL;DR: The Wolf-Rayet (WR) star NaSt1 as mentioned in this paper has a disc-like geometry tilted ≈12° from edge-on, composed of a bright central ellipsoid surrounded by a larger clumpy ring.
Abstract: NaSt1 (aka Wolf–Rayet 122) is a peculiar emission-line star embedded in an extended nebula of [N ii] emission with a compact dusty core. The object was previously characterized as a Wolf–Rayet (WR) star cloaked in an opaque nebula of CNO-processed material, perhaps analogous to η Car and its Homunculus nebula, albeit with a hotter central source. To discern the morphology of the [N ii] nebula we performed narrow-band imaging using the Hubble Space Telescope and Wide-field Camera 3. The images reveal that the nebula has a disc-like geometry tilted ≈12° from edge-on, composed of a bright central ellipsoid surrounded by a larger clumpy ring. Ground-based spectroscopy reveals radial velocity structure (±10 km s^−1) near the outer portions of the nebula's major axis, which is likely to be the imprint of outflowing gas. Near-infrared adaptive-optics imaging with Magellan AO has resolved a compact ellipsoid of K s-band emission aligned with the larger [N ii] nebula, which we suspect is the result of scattered He i line emission (λ2.06 μm). Observations with the Chandra X-ray Observatory have revealed an X-ray point source at the core of the nebula that is heavily absorbed at energies <1 keV and has properties consistent with WR stars and colliding-wind binaries. We suggest that NaSt1 is a WR binary embedded in an equatorial outflow that formed as the result of non-conservative mass transfer. NaSt1 thus appears to be a rare and important example of a stripped-envelope WR forming through binary interaction, caught in the brief Roche lobe overflow phase.
University of California, Berkeley1, Space Telescope Science Institute2, Stanford University3, Search for extraterrestrial intelligence4, University of Toronto5, Lawrence Livermore National Laboratory6, Arizona State University7, Université de Montréal8, National Research Council9, University of Victoria10, University of Grenoble11, University of California, Los Angeles12, Durham University13, Johns Hopkins University14, University of Exeter15, University of Arizona16, American Museum of Natural History17, University of California, Santa Cruz18
TL;DR: In this paper, the Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk, were obtained during the commissioning of GPI, and they detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast and northwest sides.
Abstract: We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast and northwest sides. The southeast side of the disk exhibits a bump at 1$''$ (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the northwest side at similar separations. This part of the disk is also vertically offset by 69$\pm$30 mas to the northeast at 1$''$ when compared to the established disk mid-plane and consistent with prior ALMA and Hubble Space Telescope/STIS observations. We see hints that the southeast bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively when including the morphology of the northwest side, where the disk mid-plane is offset in the opposite direction $\sim$50 mas between 0$.''$4 and 1$.''$2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for $\sim$4 $M_\mathrm{Jup}$ planets at 4 AU. We detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.
INAF1, University of Arizona2, University of Padua3, University of Virginia4, University of Edinburgh5, University of Liège6, University of Grenoble7, Max Planck Society8, University of Notre Dame9, Arizona State University10, University of California, Santa Cruz11, Ames Research Center12, University of Minnesota13
TL;DR: Maire, A-L; Skemer, AJ; Hinz, PM; Desidera, S; Esposito, S, Gratton, R; Marzari, F; Skrutskie, MF; Biller, BA; Defrere, D; Bailey, VP; Leisenring, JM; Apai, D, Bonnefoy, M; Brandner, W; Buenzli, E; Claudi, RU; Close, LM; Crepp, JR; De Rosa, RJ; Eisner, JA; Fortney
Abstract: Author(s): Maire, A-L; Skemer, AJ; Hinz, PM; Desidera, S; Esposito, S; Gratton, R; Marzari, F; Skrutskie, MF; Biller, BA; Defrere, D; Bailey, VP; Leisenring, JM; Apai, D; Bonnefoy, M; Brandner, W; Buenzli, E; Claudi, RU; Close, LM; Crepp, JR; De Rosa, RJ; Eisner, JA; Fortney, JJ; Henning, T; Hofmann, K-H; Kopytova, TG; Males, JR; Mesa, D; Morzinski, KM; Oza, A; Patience, J; Pinna, E; Rajan, A; Schertl, D; Schlieder, JE; Su, KYL; Vaz, A; Ward-Duong, K; Weigelt, G; Woodward, CE
TL;DR: In this article, the authors present high-contrast Magellan adaptive optics (MagAO) images of HD 7449, a Sun-like star with one planet and a long-term radial velocity (RV) trend.
Abstract: We present high-contrast Magellan adaptive optics (MagAO) images of HD 7449, a Sun-like star with one planet and a long-term radial velocity (RV) trend. We unambiguously detect the source of the long-term trend from 0.6-2.15 \microns ~at a separation of \about 0\fasec 54. We use the object's colors and spectral energy distribution to show that it is most likely an M4-M5 dwarf (mass \about 0.1-0.2 \msun) at the same distance as the primary and is therefore likely bound. We also present new RVs measured with the Magellan/MIKE and PFS spectrometers and compile these with archival data from CORALIE and HARPS. We use a new Markov chain Monte Carlo procedure to constrain both the mass ($> 0.17$ \msun ~at 99$\%$ confidence) and semimajor axis (\about 18 AU) of the M dwarf companion (HD 7449B). We also refine the parameters of the known massive planet (HD 7449Ab), finding that its minimum mass is $1.09^{+0.52}_{-0.19}$ \mj, its semimajor axis is $2.33^{+0.01}_{-0.02}$ AU, and its eccentricity is $0.8^{+0.08}_{-0.06}$. We use N-body simulations to constrain the eccentricity of HD 7449B to $\lesssim$ 0.5. The M dwarf may be inducing Kozai oscillations on the planet, explaining its high eccentricity. If this is the case and its orbit was initially circular, the mass of the planet would need to be $\lesssim$ 1.5 \mj. This demonstrates that strong constraints on known planets can be made using direct observations of otherwise undetectable long-period companions.
07 Jun 2015
TL;DR: In this article, a frequency-based analysis of tip-tilt on-sky data measured with the 6.5m Magellan Telescope Adaptive Optics (MagAO) system is presented.
Abstract: Frequency-based analysis of tip-tilt on-sky data measured with the 6.5m Magellan Telescope Adaptive Optics (MagAO) system is presented. Influence of system instrumentation (such as fans, pumps and louvers) in sensors’ frequency response is investigated.
DOI•
01 Jan 2015TL;DR: In this article, the phase difference between the seven GMT primary/secondary segment pairs is measured using a dispersed fringe sensor to measure the gap between adjacent mirror segments, which reduces the coherence of light across the subapertures.
Abstract: The future diffraction-limited performance of the 25.4 meter Giant Magellan Telescope (GMT) will rely on the activeand adaptive wavefront sensing measurements made by the Acquisition, Guiding, and Wavefront Sensor (AGWS)currently being designed by SAO. One subsystem of the AGWS, the phasing camera, will be responsible for measuringthe piston phase difference between the seven GMT primary/secondary segment pairs to 50 nm accuracy with full skycoverage using natural guide stars that are 6-10 arcmin off-axis while the on-axis light is used for science operations.The phasing camera will use a dispersed fringe sensor to measure the phase difference in rectangular subaperturesspanning the gaps between adjacent mirror segments. The large gap between segments (>295 mm, compared to 3 mmfor the Keck telescope) reduces the coherence of light across the subapertures, making this problem particularlychallenging. In support of the AGWS phasing camera technical goals, SAO has undertaken a series of prototypingefforts at the Magellan 6.5 meter Clay telescope to demonstrate the dispersed fringe sensor technology and validateatmospheric models. Our latest on-sky test, completed in December 2015, employs a dual-band (I and J) dispersedfringe sensor. This prototype uses an adaptive optics corrected beam from the Magellan AO adaptive secondary system.The system operates both on-axis and 6 arcmin off-axis from the natural guide star feeding the MagAO wavefrontsensor. This on-sky data will inform the development of the AGWS phasing camera design towards the GMT first light.
07 Jun 2015
TL;DR: Frequency-based analysis and comparisons of tip-tilt on-sky data registered with 6.5 Magellan Telescope Adaptive Optics (MagAO) system on April and Oct 2014 was performed.
Abstract: Frequency-based analysis and comparisons of tip-tilt on-sky data registered with 6.5 Magellan Telescope Adaptive Optics (MagAO) system on April and Oct 2014 was performed. Influence of close-loop gain and future challenges are discussed.
TL;DR: In this paper, the authors show that binary differential imaging (BDI) offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star.
Abstract: Binaries are typically excluded from direct imaging exoplanet surveys However, the recent findings of Kepler and radial velocity programs show that planets can and do form in binary systems Here, we suggest that visual binaries offer unique advantages for direct imaging We show that Binary Differential Imaging (BDI), whereby two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at high Strehl ratio, offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star We demonstrate this by observing a young visual binary separated by 4\asec ~with MagAO/Clio-2 at 39 \microns, where the Strehl ratio is high, the isoplanatic patch is large, and giant planets are bright Comparing BDI to angular differential imaging (ADI), we find that BDI's 5$\sigma$ contrast is \about 05 mags better than ADI's within \about 1\asec ~for the particular binary we observed Because planets typically reside close to their host stars, BDI is a promising technique for discovering exoplanets in stellar systems that are often ignored BDI is also 2-4$\times$ more efficient than ADI and classical reference PSF subtraction, since planets can be detected around both the target and PSF reference simultaneously We are currently exploiting this technique in a new MagAO survey for giant planets in 140 young nearby visual binaries BDI on a space-based telescope would not be limited by isoplanatism effects and would therefore be an even more powerful tool for imaging and discovering planets
TL;DR: In this article, non-redundant masking observations of the T Cha transition disk, taken at the VLT and Magellan in H, Ks, and L' bands, are presented.
Abstract: We present multi-epoch non-redundant masking observations of the T Cha transition disk, taken at the VLT and Magellan in H, Ks, and L' bands. T Cha is one of a small number of transition disks that host companion candidates discovered by high-resolution imaging techniques, with a putative companion at a position angle of 78 degrees, separation of 62 mas, and contrast at L' of 5.1 mag. We find comparable binary parameters in our re-reduction of the initial detection images, and similar parameters in the 2011 L', 2013 NaCo L', and 2013 NaCo Ks data sets. We find a close-in companion signal in the 2012 NaCo L' dataset that cannot be explained by orbital motion, and a non-detection in the 2013 MagAO/Clio2 L' data. However, Monte-carlo simulations show that the best fits to the 2012 NaCo and 2013 MagAO/Clio2 followup data may be consistent with noise. There is also a significant probability of false non-detections in both of these data sets. We discuss physical scenarios that could cause the best fits, and argue that previous companion and scattering explanations are inconsistent with the results of the much larger dataset presented here.
TL;DR: In this paper, the authors presented high-resolution LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBTi Exozodi Exoplanet Common Hunt (LEECH) exoplanet imaging survey, and combined their imaging data with archival images, published speckle interferometry measurements, and existing spectroscopy velocity data to solve the full orbital solution and estimate component masses.
Abstract: We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBTI Exozodi Exoplanet Common Hunt (LEECH) exoplanet imaging survey. Our H, K$_s$, and L'-band observations resolve the system at angular separations <0.09". The components exhibit significant orbital motion over a span of ~7 months. We combine our imaging data with archival images, published speckle interferometry measurements, and existing spectroscopic velocity data to solve the full orbital solution and estimate component masses. The masses of the K2.0$\pm$0.5 primary and K6.5$\pm$0.5 secondary are 0.83$\pm$0.02 M$_{\odot}$ and 0.64$\pm$0.02 M$_{\odot}$, respectively. We also derive a system distance of d = 25.87$\pm$0.02 pc and revise the Galactic kinematics of NO UMa. Our revised Galactic kinematics confirm NO UMa as a nuclear member of the ~500 Myr old Ursa Major moving group and it is thus a mass and age benchmark. We compare the masses of the NO UMa binary components to those predicted by five sets of stellar evolution models at the age of the Ursa Major group. We find excellent agreement between our measured masses and model predictions with little systematic scatter between the models. NO UMa joins the short list of nearby, bright, late-type binaries having known ages and fully characterized orbits.
TL;DR: In this article, the Magellan adaptive optics (MagAO) system and its VisAO CCD camera were used to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths.
Abstract: We used the Magellan adaptive optics (MagAO) system and its VisAO CCD camera to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths. We detect it at r', i', z', and Ys. With our new photometry and Teff~2500 K derived from the shape its K-band spectrum, we find that CT Cha B has Av = 3.4+/-1.1 mag, and a mass of 14-24 Mj according to the DUSTY evolutionary tracks and its 1-5 Myr age. The overluminosity of our r' detection indicates that the companion has significant Halpha emission and a mass accretion rate ~6*10^-10 Msun/yr, similar to some substellar companions. Proper motion analysis shows that another point source within 2" of CT Cha A is not physical. This paper demonstrates how visible wavelength AO photometry (r', i', z', Ys) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions.