Iras-allsky

Spitzer Microlensing Parallax for OGLE-2016-BLG-1067: A Sub-Jupiter Orbiting an M Dwarf in the Disk

March 2019 • 2019AJ....157..121C

Authors • Calchi Novati, S. • 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. • Spitzer Team • 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. • MOA Collaboration • Mróz, P. • Poleski, R. • Skowron, J. • Szymański, M. K. • Soszyński, I. • Kozłowski, S. • Pietrukowicz, P. • Ulaczyk, K. • Pawlak, M. • OGLE Collaboration • 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. • KMTNet Collaboration

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 planetary microlensing anomalies toward the Galactic bulge. Most of the microlensing parameters are strongly constrained by the light-curve modeling, and in particular there is a Spitzer-based measurement of the microlens parallax, π E. However, there are no caustic crossings, so the angular Einstein radius has only an upper limit based on the light-curve modeling alone. Additionally, the analysis leads us to identify eight degenerate configurations: the fourfold microlensing parallax degeneracy being doubled by a degeneracy in the caustic structure present at the level of the ground-based solutions. To calculate the physical parameters, and at the same time to break the parallax degeneracy, we make use of a series of arguments: the χ 2 hierarchy, the Rich argument (stating that the small-parallax solution is more likely), and a prior Galactic model. The preferred configuration, favored by a likelihood ratio of at least 4000, is for a host at {D}L={3.73}-0.67+0.66 {kpc} with mass {M}{{L}}={0.30}-0.12+0.15 {M}, orbited by a Saturn-like planet with {M}planet} ={0.43}-0.17+0.21 {M}Jup} at projected separation {a}\perp ={1.70}-0.39+0.38 {au}, about 2.1 times beyond the system snow line. Therefore, it adds to the growing population of sub-Jupiter planets orbiting 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.

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IPAC Authors
(alphabetical)

Fotina

Sebastiano Calchi Novati

Associate Scientist


Sean Carey

Senior Scientist