OGLE-2008-BLG-355Lb: A MASSIVE PLANET AROUND A LATE-TYPE STAR

作者：Koshimoto N^*; Udalski A; Sumi T; Bennett D P; Bond I A; Rattenbury N; Abe F; Botzler C S; Freeman M; Fukagawa M; Fukui A; Furusawa K; Itow Y; Ling C H; Masuda K; Matsubara Y; Muraki Y; Ohnishi K; Saito To; Shibai H; Sullivan D J; Suzuki K; Suzuki D; Sweatman W L; Takino S; Tristram P J; Wada K; Yock P C M; Szymanski M K; Kubiak M; Soszynski I; Pietrzynski G; Poleski R; Ulaczyk K; Wyrzykowski L

来源：Astrophysical Journal, 2014, 788(2): 128.

DOI：10.1088/0004-637X/788/2/128

• gravitational lensing: micro
• planetary systems

We report the discovery of a massive planet, OGLE-2008-BLG-355Lb. The light curve analysis indicates a planet: host mass ratio of q = 0.0118 +/- 0.0006 at a separation of 0.877 +/- 0.010 Einstein radii. We do not measure a significant microlensing parallax signal and do not have high angular resolution images that could detect the planetary host star. Therefore, we do not have a direct measurement of the host star mass. A Bayesian analysis, assuming that all host stars have equal probability to host a planet with the measured mass ratio, implies a host star mass of M-h = 0.37(0.17)(+0.30)M and a companion of mass M-P = 4.6(2.2)(+ 3.7)M(J), at a projected separation of r(perpendicular to) = 1.70(0.30)(+0.29) AU. The implied distance to the planetary system is DL = 6.8 +/- 1.1 kpc. A planetary system with the properties preferred by the Bayesian analysis may be a challenge to the core accretion model of planet formation, as the core accretion model predicts that massive planets are far more likely to form around more massive host stars. This core accretion model prediction is not consistent with our Bayesian prior of an equal probability of host stars of all masses to host a planet with the measured mass ratio. Thus, if the core accretion model prediction is right, we should expect that follow-up high angular resolution observations will detect a host star with a mass in the upper part of the range allowed by the Bayesian analysis. That is, the host would probably be a K or G dwarf.

• 出版日期2014-6-20
• 单位中国科学院国家天文台