학술논문
Spitzer Microlensing Parallax for OGLE-2016-BLG-1067: a sub-Jupiter Orbiting an M-dwarf in the Disk
Document Type
Working Paper
Author
Novati, S. Calchi; Suzuki, D.; Udalski, A.; Gould, A.; Shvartzvald, Y.; Bozza, V.; Bennett, D. P.; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Yee, J. C.; Zhu, W.; Abe, F.; Asakura, Y.; Barry, R.; Bhattacharya, A.; Bond, I. A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Kawasaki, K.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Matsubara, Y.; Miyazaki, S.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Ranc, C.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Sumi, T.; Tristram, P. J.; Yamada, T.; Yonehara, A.; Mróz, P.; Poleski, R.; Skowron, J.; Szymański, M. K.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; Albrow, M. D.; Chung, S. -J.; Han, C.; Hwang, K. -H.; Jung, Y. K.; Ryu, Y. -H.; Shin, I. -G.; Zang, W.; Cha, S. -M.; Kim, D. -J.; Kim, H. -W.; Kim, S. -L.; Lee, C. -U.; Lee, D. -J.; Lee, Y.; Park, B. -G.; Pogge, R. W.
Source
Subject
Language
Abstract
We report the discovery of a sub-Jupiter mass planet orbiting beyond the snow line of an M-dwarf most likely in the Galactic disk as part of the joint Spitzer and ground-based monitoring of microlensing planetary anomalies toward the Galactic bulge. The microlensing parameters are strongly constrained by the light curve modeling and in particular by the Spitzer-based measurement of the microlens parallax, $\pi_\mathrm{E}$. However, in contrast to many planetary microlensing events, there are no caustic crossings, so the angular Einstein radius, $\theta_\mathrm{E}$ has only an upper limit based on the light curve modeling alone. Additionally, the analysis leads us to identify 8 degenerate configurations: the four-fold microlensing parallax degeneracy being doubled by a degeneracy in the caustic structure present at the level of the ground-based solutions. To pinpoint the physical parameters, and at the same time to break the parallax degeneracy, we make use of a series of arguments: the $\chi^2$ hierarchy, the Rich argument, and a prior Galactic model. The preferred configuration is for a host at $D_L=3.73_{-0.67}^{+0.66}~\mathrm{kpc}$ with mass $M_\mathrm{L}=0.30_{-0.12}^{+0.15}~\mathrm{M_\odot}$, orbited by a Saturn-like planet with $M_\mathrm{planet}=0.43_{-0.17}^{+0.21}~\mathrm{M_\mathrm{Jup}}$ at projected separation $a_\perp = 1.70_{-0.39}^{+0.38}~\mathrm{au}$, about 2.1 times beyond the system snow line. Therefore, it adds to the growing population of sub-Jupiter planets orbiting near or beyond the snow line of M-dwarfs discovered by microlensing. Based on the rules of the real-time protocol for the selection of events to be followed up with Spitzer, this planet will not enter the sample for measuring the Galactic distribution of planets.
Comment: Submitted to AAS Journals
Comment: Submitted to AAS Journals