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Published March 2022 | Accepted Version + Published
Journal Article Open

OGLE-2014-BLG-0319: A Sub-Jupiter-mass Planetary Event Encountered Degeneracy with Different Mass Ratios and Lens-source Relative Proper Motions

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)^(+0.35) M_(Jup) sub-Jovian planet orbiting a 0.47_(-0.25)^(0.33) M_⊙ 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.

Additional Information

© 2022. The American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 October 25; revised 2021 December 17; accepted 2021 December 27; published 2022 February 10. We appreciate the anonymous referee for helping to improve the paper. We acknowledge the following support. Work by S.M. is supported by JSPS KAKENHI grant No. 21J11296. The work of D.P.B., N.K., C.R., Y.H., and A.B. was supported by NASA under award No. 80GSFC17M0002. C.R. is supported by the ANR project COLD-WORLDS of the French Agence Nationale de la Recherche with the reference ANR-18-CE31-0002. The MOA project is supported by JSPS KAKENHI grant Nos. 19KK0082 and 20H04754.

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Published - Miyazaki_2022_AJ_163_123.pdf

Accepted Version - 2112.14997.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023