Author
I.-G. Shin
Other affiliations: Harvard University, Smithsonian Astrophysical Observatory, Max Planck Society
Bio: I.-G. Shin is an academic researcher from Chungbuk National University. The author has contributed to research in topics: Gravitational microlensing & Light curve. The author has an hindex of 17, co-authored 27 publications receiving 1079 citations. Previous affiliations of I.-G. Shin include Harvard University & Smithsonian Astrophysical Observatory.
Papers
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University of Notre Dame1, Massey University2, Massachusetts Institute of Technology3, Goddard Space Flight Center4, Osaka University5, Institut d'Astrophysique de Paris6, University of Warsaw7, Vienna University of Technology8, University of Salerno9, Istituto Nazionale di Fisica Nucleare10, Nagoya University11, University of Auckland12, Vaughn College of Aeronautics and Technology13, Victoria University of Wellington14, University of Canterbury15, University of Toulouse16, European Southern Observatory17, University of Tasmania18, University of Rijeka19, University of St Andrews20, Chungbuk National University21, Space Telescope Science Institute22, Heidelberg University23, Texas A&M University24, Peking University25, Ohio State University26, Korea Astronomy and Space Science Institute27, Harvard University28, University of Concepción29, Queen Mary University of London30, Las Cumbres Observatory Global Telescope Network31, Royal Society32, Qatar Foundation33, Max Planck Society34, Liverpool John Moores University35, Pontifical Catholic University of Chile36, University of Manchester37, University of Hertfordshire38, Centre national de la recherche scientifique39
TL;DR: In this paper, the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M host ~ 4 Jupiter masses hosting a sub-Earth mass moon was presented.
Abstract: We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M host ~ 4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product ML πrel where ML is the lens system mass and πrel is the lens-source relative parallax. If the lens system is nearby (large πrel), then ML is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, μrel = 19.6 ± 1.6 mas yr–1, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of and , at a projected separation of AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons.
173 citations
California Institute of Technology1, Smithsonian Astrophysical Observatory2, University of Salerno3, Ohio State University4, Max Planck Society5, Korea Astronomy and Space Science Institute6, Korea University of Science and Technology7, University of Canterbury8, Kyung Hee University9, Chungbuk National University10
TL;DR: The OGLE-2016-BLG-1195Lb is the smallest known Earth-mass microlensing planet to date as mentioned in this paper at 3.91^(+0.42)_(-0.46) kpc.
Abstract: We combine Spitzer and ground-based Korea Microlensing Telescope Network microlensing observations to identify and precisely measure an Earth-mass (1.43^(+0.45)_(-0.32) M⊕) planet OGLE-2016-BLG-1195Lb at 1.16^(+0.16)_(-0.13) au orbiting a 0.078^(+0.016)_(-0.012) M⊙ ultracool dwarf. This is the lowest-mass microlensing planet to date. At 3.91^(+0.42)_(-0.46) kpc, it is the third consecutive case among the Spitzer "Galactic distribution" planets toward the Galactic bulge that lies in the Galactic disk as opposed to the bulge itself, hinting at a skewed distribution of planets. Together with previous microlensing discoveries, the seven Earth-size planets orbiting the ultracool dwarf TRAPPIST-1, and the detection of disks around young brown dwarfs, OGLE-2016-BLG-1195Lb suggests that such planets might be common around ultracool dwarfs. It therefore sheds light on the formation of both ultracool dwarfs and planetary systems at the limit of low-mass protoplanetary disks.
105 citations
Las Cumbres Observatory Global Telescope Network1, University of Warsaw2, California Institute of Technology3, University of Salerno4, University of Copenhagen5, Ohio State University6, Harvard University7, Heidelberg University8, University of Notre Dame9, University of St Andrews10, Qatar Foundation11, Istituto Nazionale di Fisica Nucleare12, University of Hamburg13, Institut d'Astrophysique de Paris14, Max Planck Society15, Peking University16, Keele University17, Chinese Academy of Sciences18, Korea Astronomy and Space Science Institute19, European Southern Observatory20, Space Telescope Science Institute21, University of Antofagasta22, Pontifical Catholic University of Chile23, Sharif University of Technology24, Aarhus University25, Open University26, Liverpool John Moores University27, University of Warwick28, Nagoya University29, Massey University30, University of Auckland31, Osaka University32, Kyoto Sangyo University33, Vaughn College of Aeronautics and Technology34, Victoria University of Wellington35, Chungbuk National University36
TL;DR: In this paper, the authors reported the detection of a cold Neptune mplanet = 21 ± 2 M⊕ orbiting a 0.38 m⊙ M dwarf lying 2.5-3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations.
Abstract: We report the detection of a cold Neptune mplanet = 21 ± 2 M⊕ orbiting a 0.38 M⊙ M dwarf lying 2.5–3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real-time protocols described by Yee et al., which aim to maximize planet sensitivity while maintaining sample integrity, have been carried out in practice. Multiple survey and follow up teams successfully combined their efforts within the framework of these protocols to detect this planet. This is the second planet in the Spitzer Galactic distribution sample. Both are in the near to mid-disk and are clearly not in the Galactic bulge.
103 citations
TL;DR: In this article, the detection of a Cold Neptune m_planet=21+/-2M orbiting a 0.38MSol M dwarf lying 2.5-3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations was reported.
Abstract: We report the detection of a Cold Neptune m_planet=21+/-2MEarth orbiting a 0.38MSol M dwarf lying 2.5-3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real-time protocols described by Yee et al. (2015), which aim to maximize planet sensitivity while maintaining sample integrity, have been carried out in practice. Multiple survey and follow-up teams successfully combined their efforts within the framework of these protocols to detect this planet. This is the second planet in the Spitzer Galactic distribution sample. Both are in the near-to-mid disk and clearly not in the Galactic bulge.
97 citations
Ohio State University1, Osaka University2, University of Notre Dame3, Massey University4, Chungbuk National University5, Institut d'Astrophysique de Paris6, University of Warsaw7, Las Cumbres Observatory Global Telescope Network8, Heidelberg University9, Queen Mary University of London10, University of Copenhagen11, Nagoya University12, University of Auckland13, University of British Columbia14, College of Industrial Technology15, Victoria University of Wellington16, Kyoto Sangyo University17, Texas A&M University18, Peking University19, Korea Astronomy and Space Science Institute20, Auckland University of Technology21, Harvard University22, Qatar Foundation23, University of St Andrews24, Russian Academy of Sciences25, European Southern Observatory26, Max Planck Society27, Liverpool John Moores University28
TL;DR: The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.S. as discussed by the authors.
Abstract: A.F. was supported by the Astrobiology Project of the Center for Novel Science Initiatives (CNSI), National Institutes of Natural Sciences (NINS; Grant Number AB261005). T.S. acknowledges the financial support from the JSPS, JSPS23103002, JSPS24253004, and JSPS26247023. The MOA project is supported by grants JSPS25103508 and 23340064. NJR is a Royal Society of New Zealand Rutherford Discovery Fellow. Work by C.H. was supported by Creative Research Initiative Program (2009-0081561) of National Research Foundation of Korea. S.D. is supported by "the Strategic Priority Research Program—The Emergence of Cosmological Structures" of the Chinese Academy of Sciences (grant No. 09000000). The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. C.S. received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement No. 268421. K.A., D.M.B., M.D., K.H., M.H., C.L., C.S., R.A.S., and Y.T. would like to thank the Qatar Foundation for support from QNRF grant NPRP-09-476-1-078.
62 citations
Cited by
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University of North Carolina at Chapel Hill1, University of Texas at Austin2, University of Hawaii3, University of California, Berkeley4, Planetary Science Institute5, Australian National University6, Manhattan College7, Massachusetts Institute of Technology8, University of North Georgia9, Rochester Institute of Technology10
255 citations
TL;DR: In this article, the authors report the results of the statistical analysis of planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012, and determine the survey sensitivity as a function of planet star mass ratio, q, and projected planet star separation, s, in Einstein radius units.
Abstract: We report the results of the statistical analysis of planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012. We determine the survey sensitivity as a function of planet star mass ratio, q, and projected planet star separation, s, in Einstein radius units. We find that the mass-ratio function is not a single power law, but has a change in slope at q approx.10(exp -4), corresponding to approx. 20 Stellar Mass for the median host-star mass of approx. 0.6 M. We find significant planetary signals in 23 of the 1474 alert events that are well-characterized by the MOA-II survey data alone. Data from other groups are used only to characterize planetary signals that have been identified in the MOA data alone. The distribution of mass ratios and separations of the planets found in our sample are well fit by a broken power-law model. We also combine this analysis with the previous analyses of Gould et al. and Cassan et al., bringing the total sample to 30 planets. The unbroken power-law model is disfavored with a p-value of 0.0022, which corresponds to a Bayes factor of 27 favoring the broken power-law model. These results imply that cold Neptunes are likely to be the most common type of planets beyond the snow line.
227 citations
TL;DR: The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses as mentioned in this paper, and there is a growing need for both a higher-precision relation and a better understanding of systematic effects (e.g., metallicity).
Abstract: The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses. However, there is growing need for both a higher-precision relation and a better understanding of systematic effects (e.g., metallicity). Here we present an empirical relationship between Mks and mass spanning $0.075M_\odot
216 citations
TL;DR: In this paper, it was shown that Earth mass planets orbiting stars in the Galactic disk and bulge can be detected by monitoring microlensed stars in a Galactic bulge, and that the planetary signal remains detectable for planetary masses as small as an Earth mass when realistic source star sizes are included in the lightcurve calculation.
Abstract: We show that Earth mass planets orbiting stars in the Galactic disk and bulge can be detected by monitoring microlensed stars in the Galactic bulge. The star and its planet act as a binary lens which generates a lightcurve which can differ substantially from the lightcurve due only to the star itself. We show that the planetary signal remains detectable for planetary masses as small as an Earth mass when realistic source star sizes are included in the lightcurve calculation. These planets are detectable if they reside in the ``lensing zone" which is centered between 1 and 4 AU from the lensing star and spans about a factor of 2 in distance. If we require a minimum deviation of 4\% from the standard point-lens microlensing lightcurve, then we find that more than 2\% of all $\mearth$ planets and 10\% of all $10\mearth$ in the lensing zone can be detected. If a third of all lenses have no planets, a third have $1\mearth$ planets and the remaining third have $10\mearth$ planets then we estimate that an aggressive ground based microlensing planet search program could find one earth mass planet and half a dozen $10\mearth$ planets per year.
210 citations
TL;DR: For the first time, the source and the lens of OGLE-2005-BLG-169Lb were completely resolved, providing a precise measurement of their heliocentric relative proper motion as mentioned in this paper.
Abstract: We present Keck NIRC2 high angular resolution adaptive optics observations of the microlensing event OGLE-2005-BLG-169Lb, taken 8.21 years after the discovery of this planetary system. For the first time for a microlensing planetary event, the source and the lens are completely resolved, providing a precise measurement of their heliocentric relative proper motion, ${\mu }_{\mathrm{rel},\mathrm{helio}}=7.44\pm 0.17$ mas yr−1. This confirms and refines the initial model presented in the discovery paper and rules out a range of solutions that were allowed by the microlensing light curve. This is also the first time that parameters derived from a microlensing planetary signal are confirmed, both with the Keck measurements, presented in this paper, and independent measurements obtained with the Hubble Space Telescope in $I,V$ and B bands, presented in a companion paper. Hence, this new measurement of ${\mu }_{\mathrm{rel},\mathrm{helio}}$, as well as the measured brightness of the lens in H band, enabled the mass and distance of the system to be updated: a Uranus-mass planet (${m}_{{\rm{p}}}=13.2\pm 1.3{M}_{\oplus }$) orbiting a K5-type main sequence star (${M}_{*}=0.65\pm 0.05{M}_{\odot }$) separated by ${a}_{\perp }=3.4\pm 0.3$ AU, at the distance ${D}_{{\rm{L}}}=4.0\pm 0.4$ kpc from us.
158 citations