OGLE-2015-BLG-1649Lb: A Gas Giant Planet around a Low-mass Dwarf

OGLE Collaboration; FUN Collaboration; MOA Collaboration; PLANET RoboNet Collaboration

doi:10.3847/1538-3881/ab4881

OGLE-2015-BLG-1649Lb: A Gas Giant Planet around a Low-mass Dwarf

OGLE Collaboration; FUN Collaboration; MOA Collaboration; PLANET RoboNet Collaboration

Abstract

We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10⁻³ and the projected separation normalized to the angular Einstein radius is s = 0.9. We conducted high-resolution follow-up observations using the Infrared Camera and Spectrograph (IRCS) camera on the Subaru telescope and are able to place an upper limit on the lens flux. From these measurements we are able to exclude all host stars greater than or equal in mass to a G-type dwarf. We conducted a Bayesian analysis with these new flux constraints included as priors resulting in estimates of the masses of the host star and planet. These are M_L = 0.34 ± 0.19 M_☉ and M_p = 2.5_-_1.4^+1.5 M_Jup, respectively. The distance to the system is D_L = 4.23_-_1.64^+1.51 kpc. The projected star–planet separation is a_⊥ = 2.07_-_0.77^+0.65 au. The estimated relative lens-source proper motion, ∼7.1 mas yr⁻¹, is fairly high and thus the lens can be better constrained if additional follow-up observations are conducted several years after the event.

Original language	English
Article number	212
Journal	Astronomical Journal
Volume	158
Issue number	5
Number of pages	9
ISSN	0004-6256
DOIs	https://doi.org/10.3847/1538-3881/ab4881
Publication status	Published - 1 Nov 2019

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@article{02f4bdb6c04b463ca9f1d549ecfa74b2,

title = "OGLE-2015-BLG-1649Lb: A Gas Giant Planet around a Low-mass Dwarf",

abstract = "We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10−3 and the projected separation normalized to the angular Einstein radius is s = 0.9. We conducted high-resolution follow-up observations using the Infrared Camera and Spectrograph (IRCS) camera on the Subaru telescope and are able to place an upper limit on the lens flux. From these measurements we are able to exclude all host stars greater than or equal in mass to a G-type dwarf. We conducted a Bayesian analysis with these new flux constraints included as priors resulting in estimates of the masses of the host star and planet. These are ML = 0.34 ± 0.19 M☉ and Mp = 2.5-1.4+1.5 MJup, respectively. The distance to the system is DL = 4.23-1.64+1.51 kpc. The projected star–planet separation is a⊥ = 2.07-0.77+0.65 au. The estimated relative lens-source proper motion, ∼7.1 mas yr−1, is fairly high and thus the lens can be better constrained if additional follow-up observations are conducted several years after the event.",

author = "M. Nagakane and Chien-Hsiu Lee and N. Koshimoto and D. Suzuki and A. Udalski and Beaulieu, {J. P.} and T. Sumi and Bennett, {D. P.} and Bond, {I. A.} and N. Rattenbury and E. Bachelet and M. Dominik and F. Abe and Barry, {R. K.} and A. Bhattacharya and M. Donachie and H. Fujii and A. Fukui and Y. Hirao and Y. Itow and Y. Kamei and I Kondo and Li, {M. C. A.} and Y. Matsubara and T. Matsuo and S. Miyazaki and Y. Muraki and C. Ranc and H. Shibai and H. Suematsu and Sullivan, {D. J.} and Tristram, {P. J.} and T. Yamakawa and A. Yonehara and P. Mroz and R. Poleski and J. Skowron and Szymanski, {M. K.} and I Soszynski and P. Pietrukowicz and S. Kozlowski and K. Ulaczyk and Bramich, {D. M.} and A. Cassan and {Figuera Jaimes}, R. and K. Horne and M. Hundertmark and Jorgensen, {U. G.} and Andersen, {M., I} and H. Korhonen and {OGLE Collaboration; FUN Collaboration; MOA Collaboration; PLANET RoboNet Collaboration}",

year = "2019",

month = nov,

day = "1",

doi = "10.3847/1538-3881/ab4881",

language = "English",

volume = "158",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "Institute of Physics Publishing, Inc",

number = "5",

}

TY - JOUR

T1 - OGLE-2015-BLG-1649Lb

T2 - A Gas Giant Planet around a Low-mass Dwarf

AU - Nagakane, M.

AU - Lee, Chien-Hsiu

AU - Koshimoto, N.

AU - Suzuki, D.

AU - Udalski, A.

AU - Beaulieu, J. P.

AU - Sumi, T.

AU - Bennett, D. P.

AU - Bond, I. A.

AU - Rattenbury, N.

AU - Bachelet, E.

AU - Dominik, M.

AU - Abe, F.

AU - Barry, R. K.

AU - Bhattacharya, A.

AU - Donachie, M.

AU - Fujii, H.

AU - Fukui, A.

AU - Hirao, Y.

AU - Itow, Y.

AU - Kamei, Y.

AU - Kondo, I

AU - Li, M. C. A.

AU - Matsubara, Y.

AU - Matsuo, T.

AU - Miyazaki, S.

AU - Muraki, Y.

AU - Ranc, C.

AU - Shibai, H.

AU - Suematsu, H.

AU - Sullivan, D. J.

AU - Tristram, P. J.

AU - Yamakawa, T.

AU - Yonehara, A.

AU - Mroz, P.

AU - Poleski, R.

AU - Skowron, J.

AU - Szymanski, M. K.

AU - Soszynski, I

AU - Pietrukowicz, P.

AU - Kozlowski, S.

AU - Ulaczyk, K.

AU - Bramich, D. M.

AU - Cassan, A.

AU - Figuera Jaimes, R.

AU - Horne, K.

AU - Hundertmark, M.

AU - Jorgensen, U. G.

AU - Andersen, M., I

AU - Korhonen, H.

AU - OGLE Collaboration; FUN Collaboration; MOA Collaboration; PLANET RoboNet Collaboration

PY - 2019/11/1

Y1 - 2019/11/1

N2 - We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10−3 and the projected separation normalized to the angular Einstein radius is s = 0.9. We conducted high-resolution follow-up observations using the Infrared Camera and Spectrograph (IRCS) camera on the Subaru telescope and are able to place an upper limit on the lens flux. From these measurements we are able to exclude all host stars greater than or equal in mass to a G-type dwarf. We conducted a Bayesian analysis with these new flux constraints included as priors resulting in estimates of the masses of the host star and planet. These are ML = 0.34 ± 0.19 M☉ and Mp = 2.5-1.4+1.5 MJup, respectively. The distance to the system is DL = 4.23-1.64+1.51 kpc. The projected star–planet separation is a⊥ = 2.07-0.77+0.65 au. The estimated relative lens-source proper motion, ∼7.1 mas yr−1, is fairly high and thus the lens can be better constrained if additional follow-up observations are conducted several years after the event.

AB - We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10−3 and the projected separation normalized to the angular Einstein radius is s = 0.9. We conducted high-resolution follow-up observations using the Infrared Camera and Spectrograph (IRCS) camera on the Subaru telescope and are able to place an upper limit on the lens flux. From these measurements we are able to exclude all host stars greater than or equal in mass to a G-type dwarf. We conducted a Bayesian analysis with these new flux constraints included as priors resulting in estimates of the masses of the host star and planet. These are ML = 0.34 ± 0.19 M☉ and Mp = 2.5-1.4+1.5 MJup, respectively. The distance to the system is DL = 4.23-1.64+1.51 kpc. The projected star–planet separation is a⊥ = 2.07-0.77+0.65 au. The estimated relative lens-source proper motion, ∼7.1 mas yr−1, is fairly high and thus the lens can be better constrained if additional follow-up observations are conducted several years after the event.

U2 - 10.3847/1538-3881/ab4881

DO - 10.3847/1538-3881/ab4881

M3 - Journal article

SN - 0004-6256

VL - 158

JO - Astronomical Journal

JF - Astronomical Journal

IS - 5

M1 - 212

ER -

OGLE-2015-BLG-1649Lb: A Gas Giant Planet around a Low-mass Dwarf

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