Showing papers by "Katie M. Morzinski published in 2017"
Arizona State University1, Université de Montréal2, University of California, Berkeley3, Ames Research Center4, Stanford University5, National Research Council6, University of Victoria7, Harvard University8, Space Telescope Science Institute9, Los Alamos National Laboratory10, Lawrence Livermore National Laboratory11, University of California, Los Angeles12, University of Arizona13, National Institutes of Natural Sciences, Japan14, Princeton University15, University of Toronto16, University of Georgia17, University of Grenoble18, University of California, Santa Cruz19, University of Michigan20, Search for extraterrestrial intelligence21, University of California, San Diego22, University of Western Ontario23, Stony Brook University24, California Institute of Technology25, American Museum of Natural History26, Cornell University27, The Aerospace Corporation28, Johns Hopkins University29
TL;DR: In this paper, the authors proposed a method to detect exoplanets using the ESI program for GPI related to NASA's Exoplanets Research Program (XRP) and NExSS (NExSS).
Abstract: NSF [AST1411868, AST-1518332, DGE-1311230]; NASA [NNX14AJ80G]; Fonds de Recherche du Quebec; NASA Exoplanets Research Program (XRP) [NNX16AD44G]; JPL's ESI program for GPIrelated; NASA's Science Mission Directorate; NExSS [NNX15AD95G]; U.S. Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344]
137 citations
Amherst College1, Stanford University2, Université de Montréal3, University of Arizona4, Space Telescope Science Institute5, University of California, Berkeley6, University of Grenoble7, National Research Council8, University of Victoria9, California Institute of Technology10, Lawrence Livermore National Laboratory11, Subaru12, University of Toronto13, University of Georgia14, University of California, Los Angeles15, Durham University16, Johns Hopkins University17, European Southern Observatory18, Search for extraterrestrial intelligence19, University of California, San Diego20, University of Western Ontario21, American Museum of Natural History22, Arizona State University23, Cornell University24, The Aerospace Corporation25
TL;DR: In this paper, the Magellan Adaptive Optics system (MAGAO) and the Gemini Planet Imager (GPI) were used to acquire high-contrast images of the transitional disk of HD 100546.
Abstract: We present optical and near-infrared high-contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total intensity imagery, and MagAO data are taken in Simultaneous Differential Imaging mode at Hα. The new GPI H-band total intensity data represent a significant enhancement in sensitivity and field rotation compared to previous data sets and enable a detailed exploration of substructure in the disk. The data are processed with a variety of differential imaging techniques (polarized, angular, reference, and simultaneous differential imaging) in an attempt to identify the disk structures that are most consistent across wavelengths, processing techniques, and algorithmic parameters. The inner disk cavity at 15 au is clearly resolved in multiple data sets, as are a variety of spiral features. While the cavity and spiral structures are identified at levels significantly distinct from the neighboring regions of the disk under several algorithms and with a range of algorithmic parameters, emission at the location of HD 100546 "c" varies from point-like under aggressive algorithmic parameters to a smooth continuous structure with conservative parameters, and is consistent with disk emission. Features identified in the HD 100546 disk bear qualitative similarity to computational models of a moderately inclined two-armed spiral disk, where projection effects and wrapping of the spiral arms around the star result in a number of truncated spiral features in forward-modeled images.
112 citations
TL;DR: In this paper, the authors used the S-band radar at Arecibo Observatory to observe 16 Psyche, the largest M-class asteroid in the main belt, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images to generate a 3D shape model of Psyche.
104 citations
Stanford University1, University of California, Berkeley2, Space Telescope Science Institute3, Search for extraterrestrial intelligence4, Ames Research Center5, University of California, Los Angeles6, University of Arizona7, National Institutes of Natural Sciences, Japan8, University of Toronto9, University of Georgia10, Université de Montréal11, University of Grenoble12, University of Victoria13, National Research Council14, University of Michigan15, University of California, San Diego16, Stony Brook University17, University of Western Ontario18, California Institute of Technology19, American Museum of Natural History20, Lawrence Livermore National Laboratory21, Arizona State University22, Cornell University23, University of California, Santa Cruz24, Johns Hopkins University25
TL;DR: In this paper, a matched-filter algorithm for direct detection of point sources in the immediate vicinity of bright stars is presented, where the stellar point spread function (PSF) is first subtracted using a Karhunen-Loeve image processing (KLIP) algorithm with angular and spectral differential imaging (ADI and SDI).
Abstract: We present a new matched-filter algorithm for direct detection of point sources in the immediate vicinity of bright stars. The stellar point-spread function (PSF) is first subtracted using a Karhunen-Loeve image processing (KLIP) algorithm with angular and spectral differential imaging (ADI and SDI). The KLIP-induced distortion of the astrophysical signal is included in the matched-filter template by computing a forward model of the PSF at every position in the image. To optimize the performance of the algorithm, we conduct extensive planet injection and recovery tests and tune the exoplanet spectra template and KLIP reduction aggressiveness to maximize the signal-to-noise ratio (S/N) of the recovered planets. We show that only two spectral templates are necessary to recover any young Jovian exoplanets with minimal S/N loss. We also developed a complete pipeline for the automated detection of point-source candidates, the calculation of receiver operating characteristics (ROC), contrast curves based on false positives, and completeness contours. We process in a uniform manner more than 330 data sets from the Gemini Planet Imager Exoplanet Survey and assess GPI typical sensitivity as a function of the star and the hypothetical companion spectral type. This work allows for the first time a comparison of different detection algorithms at a survey scale accounting for both planet completeness and false-positive rate. We show that the new forward model matched filter allows the detection of 50% fainter objects than a conventional cross-correlation technique with a Gaussian PSF template for the same false-positive rate.
98 citations
TL;DR: In this paper, the authors presented spectro-photometry spanning 1-5$m of 51 Eridani b, a 2-10 M$_\text{Jup}$ planet discovered by the Gemini Planet Imager Exoplanet Survey.
Abstract: We present spectro-photometry spanning 1-5 $\mu$m of 51 Eridani b, a 2-10 M$_\text{Jup}$ planet discovered by the Gemini Planet Imager Exoplanet Survey. In this study, we present new $K1$ (1.90-2.19 $\mu$m) and $K2$ (2.10-2.40 $\mu$m) spectra taken with the Gemini Planet Imager as well as an updated $L_P$ (3.76 $\mu$m) and new $M_S$ (4.67 $\mu$m) photometry from the NIRC2 Narrow camera. The new data were combined with $J$ (1.13-1.35 $\mu$m) and $H$ (1.50-1.80 $\mu$m) spectra from the discovery epoch with the goal of better characterizing the planet properties. 51 Eri b photometry is redder than field brown dwarfs as well as known young T-dwarfs with similar spectral type (between T4-T8) and we propose that 51 Eri b might be in the process of undergoing the transition from L-type to T-type. We used two complementary atmosphere model grids including either deep iron/silicate clouds or sulfide/salt clouds in the photosphere, spanning a range of cloud properties, including fully cloudy, cloud free and patchy/intermediate opacity clouds. Model fits suggest that 51 Eri b has an effective temperature ranging between 605-737 K, a solar metallicity, a surface gravity of $\log$(g) = 3.5-4.0 dex, and the atmosphere requires a patchy cloud atmosphere to model the SED. From the model atmospheres, we infer a luminosity for the planet of -5.83 to -5.93 ($\log L/L_{\odot}$), leaving 51 Eri b in the unique position as being one of the only directly imaged planet consistent with having formed via cold-start scenario. Comparisons of the planet SED against warm-start models indicates that the planet luminosity is best reproduced by a planet formed via core accretion with a core mass between 15 and 127 M$_{\oplus}$.
97 citations
University of Toronto1, Space Telescope Science Institute2, University of California, Berkeley3, Stanford University4, University of Arizona5, Lawrence Livermore National Laboratory6, University of Western Ontario7, National Institutes of Natural Sciences, Japan8, Princeton University9, University of Georgia10, University of California, Santa Cruz11, Université de Montréal12, University of Victoria13, National Research Council14, University of Grenoble15, University of California, Los Angeles16, Durham University17, University of Michigan18, European Southern Observatory19, Search for extraterrestrial intelligence20, University of California, San Diego21, Ames Research Center22, California Institute of Technology23, American Museum of Natural History24, Arizona State University25, Universities Space Research Association26, Cornell University27, The Aerospace Corporation28, Johns Hopkins University29
TL;DR: Gemini Observatory, Dunlap Institute, University of Toronto, NSF Center for Adaptive Optics at UC Santa Cruz; NSF [AST-0909188], AST-1211562, AST-1405505] as mentioned in this paper.
Abstract: Gemini Observatory; Dunlap Institute, University of Toronto; NSF Center for Adaptive Optics at UC Santa Cruz; NSF [AST-0909188, AST-1211562, AST-1405505]; NASA Origins [NNX11AD21G, NNX10AH31G, NNX14AC21G, NNX15AC89G]; NASA NExSS [NNX15AD95G]; University of California Office of the President [LFRP-118057]; Science and Technology Facilities Council [ST/H002707/1]; U.S. Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344]; California Institute of Technology/Jet Propulsion Laboratory - NASA through Sagan Fellowship Program; NASA Exoplanets Research Program (XRP) [NNX16AD44G]; NASA through Hubble Fellowship - Space Telescope Science Institute [51378.01-A]; NASA [NAS5-26555]; NASAs Science Mission Directorate
97 citations
Université de Montréal1, Amherst College2, Stanford University3, Space Telescope Science Institute4, National Research Council5, University of Victoria6, California Institute of Technology7, University of California, Berkeley8, Search for extraterrestrial intelligence9, University of Toronto10, University of Arizona11, Stony Brook University12, University of Western Ontario13, Johns Hopkins University14, Lawrence Livermore National Laboratory15, Subaru16, University of Georgia17, University of Grenoble18, University of California, Los Angeles19, Durham University20, University of Michigan21, European Southern Observatory22, University of California, San Diego23, American Museum of Natural History24, Arizona State University25, Ames Research Center26, Cornell University27, The Aerospace Corporation28
TL;DR: In this paper, the authors used the Sagan Fellowship Program to train a team of researchers at the Lawrence Livermore National Laboratory (LNL) in order to conduct experiments on the Mars Curiosity rover.
Abstract: DPAC; Fonds de Recherche du Quebec; NASA through the Sagan Fellowship Program; NSF [AST-1411868, AST-141378]; NASA [NNX14AJ80G, NNX15AD95G, NNX16AD44G]; U.S. Department of Energy by the Lawrence Livermore National Laboratory [DE-AC52-07NA27344]
83 citations
University of Toronto1, Space Telescope Science Institute2, University of California, Berkeley3, Stanford University4, University of Arizona5, Lawrence Livermore National Laboratory6, University of Western Ontario7, Subaru8, Princeton University9, University of Georgia10, University of California, Santa Cruz11, Université de Montréal12, National Research Council13, University of California, Los Angeles14, University of Michigan15, European Southern Observatory16, University of California, San Diego17, Search for extraterrestrial intelligence18, Ames Research Center19, American Museum of Natural History20, Arizona State University21, Universities Space Research Association22, Cornell University23, California Institute of Technology24, The Aerospace Corporation25, Johns Hopkins University26
TL;DR: In this paper, the Gemini Planet Imager (GPI) was used to measure the near-infrared (1.0-2.4 micron) spectrum of the planetary companion to the nearby, young star Pictoris.
Abstract: Using the Gemini Planet Imager (GPI) located at Gemini South, we measured the near-infrared (1.0-2.4 micron) spectrum of the planetary companion to the nearby, young star $\beta$ Pictoris. We compare the spectrum obtained with currently published model grids and with known substellar objects and present the best matching models as well as the best matching observed objects. Comparing the empirical measurement of the bolometric luminosity to evolutionary models, we find a mass of $12.9\pm0.2$ $\mathcal{M}_\mathrm{Jup}$, an effective temperature of $1724\pm15$ K, a radius of $1.46\pm0.01$ $\mathcal{R}_\mathrm{Jup}$, and a surface gravity of $\log g = 4.18\pm0.01$ [dex] (cgs). The stated uncertainties are statistical errors only, and do not incorporate any uncertainty on the evolutionary models. Using atmospheric models, we find an effective temperature of $1700-1800$ K and a surface gravity of $\log g = 3.5$-$4.0$ [dex] depending upon model. These values agree well with other publications and with "hot-start" predictions from planetary evolution models. Further, we find that the spectrum of $\beta$ Pic b best matches a low-surface gravity L2$\pm$1 brown dwarf. Finally comparing the spectrum to field brown dwarfs we find the the spectrum best matches 2MASS J04062677-381210 and 2MASS J03552337+1133437.
74 citations
TL;DR: Netherlands Organization for Scientific Research (NWO); European Research Council [678194]; NASA Exoplanets Research Program (XRP) [NNX16AD44G] as mentioned in this paper.
Abstract: Netherlands Organization for Scientific Research (NWO); European Research Council [678194]; NASA Exoplanets Research Program (XRP) [NNX16AD44G]
67 citations
TL;DR: In this paper, the H band spectroscopic and Halpha photometric observations of HD 100546 obtained with GPI and MagAO were used to detect H band emission at the location of the protoplanet HD100546b, but show that choice of data processing parameters strongly affects the morphology of this source.
Abstract: We present H band spectroscopic and Halpha photometric observations of HD 100546 obtained with GPI and MagAO. We detect H band emission at the location of the protoplanet HD 100546b, but show that choice of data processing parameters strongly affects the morphology of this source. It appears point-like in some aggressive reductions, but rejoins an extended disk structure in the majority of the others. Furthermore, we demonstrate that this emission appears stationary on a timescale of 4.6 yrs, inconsistent at the 2sigma level with a Keplerian clockwise orbit at 59 au in the disk plane. The H band spectrum of the emission is inconsistent with any type of low effective temperature object or accreting protoplanetary disk. It strongly suggests a scattered light origin, as it is consistent with the spectrum of the star and the spectra extracted at other locations in the disk. A non detection at the 5sigma level of HD 100546b in differential Halpha imaging places an upper limit, assuming the protoplanet lies in a gap free of extinction, on the accretion luminosity and accretion rate of 1.7E-4 Lsun and MMdot<6.4E-7Mjup^2/yr for 1Rjup. These limits are comparable to the accretion luminosity and rate of TTauri-stars or LkCa 15b. Taken together, these lines of evidence suggest that the H band source at the location of HD 100546b is not emitted by a planetary photosphere or an accreting circumplanetary disk but is a disk feature enhanced by the PSF subtraction process. This non-detection is consistent with the non-detection in the K band reported in an earlier study but does not exclude the possibility that HD 100546b is deeply embedded.
62 citations
Stanford University1, Search for extraterrestrial intelligence2, University of California, Berkeley3, Université de Montréal4, California Institute of Technology5, National Research Council6, University of Victoria7, Aix-Marseille University8, Lawrence Livermore National Laboratory9, Brown University10, Subaru11, University of Toronto12, University of Georgia13, University of Grenoble14, University of Chicago15, University of California, Los Angeles16, Amherst College17, University of Michigan18, University of Exeter19, University of California, San Diego20, Stony Brook University21, University of Western Ontario22, University of Arizona23, University of California, Santa Cruz24, American Museum of Natural History25, Arizona State University26, Space Telescope Science Institute27, University of Cambridge28, Princeton University29, Cornell University30, Johns Hopkins University31
TL;DR: In this article, the European Commission Sixth and Seventh Framework Programmes as part of the Optical Infrared Coordination Network for Astronomy (OPTICON) were used to support ESO.
Abstract: W.M. Keck Foundation; European Organization for Astronomical Research in the Southern Hemisphere under ESO program [098.C-0864(A)]; European Commission Sixth and Seventh Framework Programmes as part of the Optical Infrared Coordination Network for Astronomy (OPTICON) [RII3-Ct-2004-001566, 226604, 312430]; Fonds de Recherche du Quebec; NASA through the Sagan Fellowship Program; NASA through Hubble Fellowship grant - Space Telescope Science Institute [51378.01-A, NAS5-26555]; NSF [AST-1411868, AST-141378, AST-1518332]; NASA [NNX14AJ80G, NNX15AC89G, NNX15AD95G, NNX16AD44G]; NRAO Student Observing Support Award [SOSPA3-007]; U.S. Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344]; NASA Science Mission Directorate; ESO
TL;DR: In this paper, the authors used the TRIF fellowship for the exploration of exoplanets in the NASA Exoplanets Research Program (XRP) (NNX16AD44G).
Abstract: National Science Foundation [1506818]; NSF AAG [1615408]; NASA Origins of Solar Systems award; TRIF fellowship; California Institute of Technology (Caltech) - NASA through the Sagan Fellowship Program; NASA Exoplanets Research Program (XRP) [NNX16AD44G]; National Science Foundation
TL;DR: In this article, the authors proposed a method to detect exoplanets through the use of NASA Exoplanets Research Program (XRP) and the W. M. Keck Foundation.
Abstract: NSF [AST-1009136, AST-1313399, AST-1509375, AST-1411654]; NASA Space Grant, through Northern Arizona University; NASA Exoplanets Research Program (XRP) [NNX16AD44G]; National Science Foundation [AST-1005313]; National Aeronautics and Space Administration; National Science Foundation; W. M. Keck Foundation
TL;DR: In this article, the feasibility and utility of using a maneuverable nanosatellite laser guide star from a geostationary equatorial orbit have been assessed to enable ground-based, adaptive optics im...
Abstract: In this study, the feasibility and utility of using a maneuverable nanosatellite laser guide star from a geostationary equatorial orbit have been assessed to enable ground-based, adaptive optics im...
TL;DR: In this paper, the authors reported the ALMA 1.3 mm and Magellan adaptive optics (MagAO) H-alpha, i', z', and Ys observations of the GQ Lup system, a classical T Tauri star with a 10-40 Mjup substellar companion at ~110 AU projected separation.
Abstract: Multi-wavelength observations provide a complementary view of the formation of young directly-imaged planet-mass companions. We report the ALMA 1.3 mm and Magellan adaptive optics (MagAO) H-alpha, i', z', and Ys observations of the GQ Lup system, a classical T Tauri star with a 10-40 Mjup substellar companion at ~110 AU projected separation. We estimate the accretion rates for both components from the observed H-alpha fluxes. In our 0.05 arcsec resolution ALMA map, we resolve GQ Lup A's disk in dust continuum, but no signal is found from the companion. The disk is compact, with a radius of ~22 AU, a dust mass of ~6 Earth masses, an inclination angle of ~56 deg, and a very flat surface density profile indicative of a radial variation in dust grain sizes. No gaps or inner cavity are found in the disk, so there is unlikely a massive inner companion to scatter GQ Lup B outward. Thus, GQ Lup B might have formed in situ via disk fragmentation or prestellar core collapse. We also show that GQ Lup A's disk is misaligned with its spin axis, and possibly with GQ Lup B's orbit. Our analysis on the tidal truncation radius of GQ Lup A's disk suggests that GQ Lup B's orbit might have a low eccentricity.
TL;DR: In this paper, the authors used the Sagan Fellowship Program under U.S. Government and National Science Foundation (NSF) to support the development of the Space Telescope Science Institute (STS-HF2-51369.
Abstract: Natural Science and Engineering Research Council (NSERC) of Canada; NASA through Hubble Fellowship grant - Space Telescope Science Institute [HST-HF2-51369.001-A]; NASA [NAS5-26555]; NASA through the Sagan Fellowship Program; CONICYT-FONDECYT [1171246]; Millennium Science Initiative (Chilean Ministry of Economy) [RC130007]; Spanish Ministerio de Economia y Competitividad [AYA 2014-55840-P]; NASA Exoplanets Research Program (XRP) [NNX16AD44G]; National Aeronautics and Space Administration; National Science Foundation; Space Telescope Science Institute under U.S. Government [NAG W-2166]
TL;DR: This work addresses the design of a minimum variance controller (MVC) for the mitigation of vibrations in modern telescope adaptive optics (AO) systems and shows that the MVC is an equivalent representation of the linear quadratic Gaussian (LQG) controller for the AO system.
Abstract: In this paper, we address the design of a minimum variance controller (MVC) for the mitigation of vibrations in modern telescope adaptive optics (AO) systems. It is widely accepted that a main source of non-turbulent perturbations is the mechanical resonance induced by the wind or the instrumentation systems, such as fans and cooling pumps. To adequately mitigate vibrations, the application of frequency-based controllers has been considered in the past decade. In this work, we express the system model in terms of the tracking of a zero-input signal via the MVC. We show that the MVC is an equivalent representation of the linear quadratic Gaussian (LQG) controller for the AO system. We also show that by developing the MVC, we can obtain different expressions, in terms of transfer functions, that offer insights into the behavior and expected performance of the controller in the frequency domain. In addition, we analyze the impact of the accuracy of the system and perturbations model on the mitigation of vibrations.
TL;DR: In this article, the authors proposed a method to detect exoplanets using the TRIF fellowship and the NASA Exoplanets Research Program (XRP) data set (NNX16AD44G).
Abstract: National Science Foundation [1506818]; NSF AAG [1615408]; NASA Origins of Solar Systems award; TRIF fellowship; NSF [AST-1312221]; NASA Exoplanets Research Program (XRP) [NNX16AD44G]
TL;DR: In this article, a vector apodizing phase plate coronagraph was used to produce three beams yielding two coronagraphic point spread functions (PSFs) and one faint leakage PSF.
Abstract: We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of $2-5 \mu$m and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The coronagraph manipulates the phase in the pupil to produce three beams yielding two coronagraphic point-spread functions (PSFs) and one faint leakage PSF. The phase pattern is imposed through the inherently achromatic geometric phase, enabled by liquid crystal technology and polarization techniques. The coronagraphic optic is manufactured using a direct-write technique for precise control of the liquid crystal pattern, and multitwist retarders for achromatization. By integrating a linear phase ramp to the coronagraphic phase pattern, two separated coronagraphic PSFs are created with a single pupil-plane optic, which makes it robust and easy to install in existing telescopes. The two coronagraphic PSFs contain a 180$^\circ$ dark hole on each side of a star, and these complementary copies of the star are used to correct the seeing halo close to the star. To characterize the coronagraph, we collected a dataset of a bright ($m_L=0-1$) nearby star with $\sim$1.5 hr of observing time. By rotating and optimally scaling one PSF and subtracting it from the other PSF, we see a contrast improvement by 1.46 magnitudes at $3.5 \lambda/D$. With regular angular differential imaging at 3.9 $\mu$m, the MagAO vector apodizing phase plate coronagraph delivers a $5\sigma\ \Delta$ mag contrast of 8.3 ($=10^{-3.3}$) at 2 $\lambda/D$ and 12.2 ($=10^{-4.8}$) at $3.5 \lambda/D$.
01 Jan 2017
TL;DR: In this paper, the authors present the design of the next generation phasing prototype for the Magellan Clay 6.5 meter telescope using an adaptive optics corrected beam from the MagAO system.
Abstract: The GMT will be a 25.4-meter telescope consisting of 7 primary and secondary mirror segments that must be phased to within a fraction of an imaging wavelength in order to achieve diffraction limited performance. The need to use off-axis guide stars, coupled with the large (350 mm) segment gaps, makes the task of phasing the GMT uniquely challenging. To meet these requirements, the Acquisition, Guiding, and Wavefront Sensing system (AGWS) will use four J-band dispersed fringe sensors (DFS) to measure segment piston at each segment boundary. This DFS will use a novel array of doublet prisms, instead of grisms, to disperse segment boundary fringes with maximal throughput, minimal stray light, and no spurious diffractive orders. The DFS will also use a low noise SAPHIRA e-APD array reading out at ~100 Hz in order to freeze atmospheric turbulence in the segment boundary fringe images. We will test a prototype of this DFS on the Magellan Clay 6.5 meter telescope using an adaptive optics corrected beam from the MagAO system. We present the design of the next generation phasing prototype.
TL;DR: In this article, the authors present diffraction-limited images (FWHM ~ 25 mas) with Magellan adaptive optics in two epochs, showing that Eta Carinae consistently appears 2.5 to 3 mas wider in H-alpha emission compared to the adjacent 643 nm continuum.
Abstract: The massive evolved star Eta Carinae is the most luminous star in the Milky Way and has the highest steady wind mass-loss rate of any known star. Radiative transfer models of the spectrum by Hillier et al. predict that H-alpha is mostly emitted in regions of the wind at radii of 6 to 60 AU from the star (2.5 to 25 mas at 2.35 kpc). We present diffraction-limited images (FWHM ~25 mas) with Magellan adaptive optics in two epochs, showing that Eta Carinae consistently appears ~2.5 to 3 mas wider in H-alpha emission compared to the adjacent 643 nm continuum. This implies that the H-alpha line-forming region may have a characteristic emitting radius of 12 mas or ~30 AU, in very good agreement with the Hillier stellar-wind model. This provides direct confirmation that the physical wind parameters of that model are roughly correct, including the mass-loss rate of 10^-3 M_sun/yr, plus the clumping factor, and the terminal velocity. Comparison of the H-alpha images (ellipticity and PA) to the continuum images reveals no significant asymmetries at H-alpha. Hence, any asymmetry induced by a companion or by the primary's rotation do not strongly influence the global H-alpha emission in the outer wind.
TL;DR: In this article, the authors image 104 newly identified low-mass (mostly M-dwarf) pre-main sequence members of nearby young moving groups with Magellan Adaptive Optics (MagAO) and identify 27 binaries with instantaneous projected separation as small as 40 mas.
Abstract: We image 104 newly identified low-mass (mostly M-dwarf) pre-main sequence members of nearby young moving groups with Magellan Adaptive Optics (MagAO) and identify 27 binaries with instantaneous projected separation as small as 40 mas. 15 were previously unknown. The total number of multiple systems in this sample including spectroscopic and visual binaries from the literature is 36, giving a raw multiplicity rate of at least $35^{+5}_{-4}\%$ for this population. In the separation range of roughly 1 - 300 AU in which infrared AO imaging is most sensitive, the raw multiplicity rate is at least $24^{+5}_{-4}\%$ for binaries resolved by the MagAO infrared camera (Clio). The M-star sub-sample of 87 stars yields a raw multiplicity of at least $30^{+5}_{-4}\%$ over all separations, $21^{+5}_{-4}\%$ for secondary companions resolved by Clio from 1 to 300 AU ($23^{+5}_{-4}\%$ for all known binaries in this separation range). A combined analysis with binaries discovered by the Search for Associations Containing Young stars shows that multiplicity fraction as a function of mass and age over the range of 0.2 to 1.2 $M_\odot$ and 10 - 200 Myr appears to be linearly flat in both parameters and across YMGs. This suggests that multiplicity rates are largely set by 100 Myr without appreciable evolution thereafter. After bias corrections are applied, the multiplicity fraction of low-mass YMG members ($< 0.6 M_\odot$) is in excess of the field.
TL;DR: In this paper, the authors have characterized the spectroscopic orbit of the TWA 3A binary and provided preliminary families of probable solutions for both the visual and the wide TWA3A--B orbit.
Abstract: We have characterized the spectroscopic orbit of the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbit as well as for the wide TWA 3A--B orbit. TWA 3 is a hierarchical triple located at 34 pc in the $\sim$10 Myr old TW Hya association. The wide component separation is 1."55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbital solution using high-resolution infrared spectroscopy which angularly resolved the A and B components. We then refined the preliminary orbit by combining the infrared data with a re-analysis of our high-resolution optical spectroscopy. The orbital period from the combined spectroscopic solution is $\sim$35 days, the eccentricity is $\sim$0.63, and the mass ratio is $\sim$0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbital solution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planes with respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least $\sim$30 degrees. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbits and disk.
Stanford University1, Search for extraterrestrial intelligence2, University of California, Berkeley3, Université de Montréal4, California Institute of Technology5, University of Victoria6, National Research Council7, Aix-Marseille University8, Lawrence Livermore National Laboratory9, Brown University10, Subaru11, University of Toronto12, University of Georgia13, University of Grenoble14, University of Chicago15, University of California, Los Angeles16, Amherst College17, University of Michigan18, University of Exeter19, University of California, San Diego20, University of Western Ontario21, Stony Brook University22, University of Arizona23, University of California, Santa Cruz24, American Museum of Natural History25, Arizona State University26, Space Telescope Science Institute27, University of Cambridge28, Princeton University29, Cornell University30, Johns Hopkins University31
TL;DR: In this article, the authors present evidence that the recently discovered, directly-imaged planet HD 131399 Ab is a background star with non-zero proper motion from new JHK1L' photometry and spectroscopy obtained with the Gemini Planet Imager, VLT/SPHERE, and Keck/NIRC2.
Abstract: We present evidence that the recently discovered, directly-imaged planet HD 131399 Ab is a background star with non-zero proper motion From new JHK1L' photometry and spectroscopy obtained with the Gemini Planet Imager, VLT/SPHERE, and Keck/NIRC2, and a reanalysis of the discovery data obtained with VLT/SPHERE, we derive colors, spectra, and astrometry for HD 131399 Ab The broader wavelength coverage and higher data quality allow us to re-investigate its status Its near-infrared spectral energy distribution excludes spectral types later than L0 and is consistent with a K or M dwarf, which are the most likely candidates for a background object in this direction at the apparent magnitude observed If it were a physically associated object, the projected velocity of HD 131399 Ab would exceed escape velocity given the mass and distance to HD 131399 A We show that HD 131399 Ab is also not following the expected track for a stationary background star at infinite distance Solving for the proper motion and parallax required to explain the relative motion of HD 131399 Ab, we find a proper motion of 123 mas/yr When compared to predicted background objects drawn from a galactic model, we find this proper motion to be high, but consistent with the top 4% fastest-moving background stars From our analysis we conclude that HD 131399 Ab is a background K or M dwarf
Amherst College1, Stanford University2, Université de Montréal3, University of Arizona4, Space Telescope Science Institute5, University of California, Berkeley6, University of Grenoble7, University of Victoria8, National Research Council9, California Institute of Technology10, Lawrence Livermore National Laboratory11, Subaru12, University of Toronto13, University of Georgia14, University of California, Los Angeles15, Durham University16, Johns Hopkins University17, European Southern Observatory18, Search for extraterrestrial intelligence19, University of California, San Diego20, University of Western Ontario21, American Museum of Natural History22, Arizona State University23, Cornell University24, The Aerospace Corporation25
TL;DR: In this paper, the authors presented optical and near-infrared high contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI).
Abstract: We present optical and near-infrared high contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total intensity imagery, and MagAO data are taken in Simultaneous Differential Imaging mode at H{\alpha}. The new GPI H -band total intensity data represent a significant enhancement in sensitivity and field rotation compared to previous data sets and enable a detailed exploration of substructure in the disk. The data are processed with a variety of differential imaging techniques (polarized, angular, reference, and simultaneous differential imaging) in an attempt to identify the disk structures that are most consistent across wavelengths, processing techniques, and algorithmic parameters. The inner disk cavity at 15 au is clearly resolved in multiple datasets, as are a variety of spiral features. While the cavity and spiral structures are identified at levels significantly distinct from the neighboring regions of the disk under several algorithms and with a range of algorithmic parameters, emission at the location of HD 100546 c varies from point-like under aggressive algorithmic parameters to a smooth continuous structure with conservative parameters, and is consistent with disk emission. Features identified in the HD100546 disk bear qualitative similarity to computational models of a moderately inclined two-armed spiral disk, where projection effects and wrapping of the spiral arms around the star result in a number of truncated spiral features in forward-modeled images.