OGLE-2014-BLG-0319: A Sub-Jupiter-mass Planetary Event Encountered Degeneracy with Different Mass Ratios and Lens-source Relative Proper Motions
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Date
2022-03-01
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Publishing on behalf of the American Astronomical Society
Rights
CC BY 4.0
Abstract
We report the discovery of a sub-Jovian-mass planet, OGLE-2014-BLG-0319Lb. The characteristics of this planet will be added into a future extended statistical analysis of the Microlensing Observations in Astrophysics (MOA) collaboration. The planetary anomaly of the light curve is characterized by MOA and OGLE survey observations and results in three degenerate models with different planetary-mass ratios of q = (10.3, 6.6, 4.5) × 10-4. We find that the last two models require unreasonably small lens-source relative proper motions of μ rel ∼1 mas yr-1. Considering Galactic prior probabilities, we rule out these two models from the final result. We conduct a Bayesian analysis to estimate physical properties of the lens system using a Galactic model and find that the lens system is composed of a 0.49-0.27+0.35MJup sub-Jovian planet orbiting a 0.47-0.25+0.33M⊙ M dwarf near the Galactic Bulge. This analysis demonstrates that Galactic priors are useful to resolve this type of model degeneracy. This is important for estimating the mass-ratio function statistically. However, this method would be unlikely successful in shorter timescale events, which are mostly due to low-mass objects, like brown dwarfs or free-floating planets. Therefore, careful treatment is needed for estimating the mass-ratio function of the companions around such low-mass hosts, which only the microlensing can probe.
Description
Keywords
Gravitational microlensing (672), Binary lens microlensing (2136), planet astronomy (486), Exoplanet detection methods (489), Exoplanets (498)
Citation
Miyazaki S, Suzuki D, Udalski A, Koshimoto N, Bennett DP, Sumi T, Rattenbury N, Cheongho H, Abe F, Barry RK, Bhattacharya A, Bond IA, Fukui A, Fujii H, Hirao Y, Silva SI, Itow Y, Kirikawa R, Kondo I, Munford B, Matsubara Y, Matsumoto S, Muraki Y, Okamura A, Olmschenk G, Ranc C, Satoh YK, Toda T, Tristram PJ, Yama H, Yonehara A, Poleski R, Mróz P, Skowron J, Szymański MK, Soszyński I, Pietrukowicz P, Kozłowski S, Ulaczyk K, Wyrzykowski Ł. (2022). OGLE-2014-BLG-0319: A Sub-Jupiter-mass Planetary Event Encountered Degeneracy with Different Mass Ratios and Lens-source Relative Proper Motions. Astronomical Journal. 163. 3.