Bibcode
Narita, Norio; Hirano, Teruyuki; Fukui, Akihiko; Hori, Yasunori; Dai, Fei; Yu, Liang; Livingston, John; Ryu, Tsuguru; Nowak, Grzegorz; Kuzuhara, Masayuki; Sato, Bun'ei; Takeda, Yoichi; Albrecht, Simon; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Palle, E.; Ribas, Ignasi; Tamura, Motohide; Van Eylen, Vincent; Winn, Joshua N.
Bibliographical reference
Publications of the Astronomical Society of Japan, Volume 69, Issue 2, id.29
Advertised on:
4
2017
Citations
9
Refereed citations
7
Description
We report on the confirmation that the candidate transits observed for
the star EPIC 211525389 are due to a short-period Neptune-sized planet.
The host star, located in K2 campaign field 5, is a metal-rich ([Fe/H] =
0.26 ± 0.05) G-dwarf (Teff = 5430 ± 70 K and
log g = 4.48 ± 0.09), based on observations with the High
Dispersion Spectrograph (HDS) on the Subaru 8.2 m telescope. High
spatial resolution AO imaging with HiCIAO on the Subaru telescope
excludes faint companions near the host star, and the false positive
probability of this target is found to be <10-6 using the
open source vespa code. A joint analysis of transit light curves from K2
and additional ground-based multi-color transit photometry with MuSCAT
on the Okayama 1.88 m telescope gives an orbital period of P = 8.266902
± 0.000070 d and consistent transit depths of
Rp/R⋆ ∼ 0.035 or
(Rp/R⋆)2 ∼ 0.0012. The transit
depth corresponds to a planetary radius of R_p = 3.59_{-0.39}^{+0.44}
R_{\oplus }, indicating that EPIC 211525389 b is a short-period
Neptune-sized planet. Radial velocities of the host star, obtained with
the Subaru HDS, lead to a 3 σ upper limit of 90
M⊕ (0.00027 M⊙) on the mass of EPIC
211525389 b, confirming its planetary nature. We expect this planet,
newly named K2-105 b, to be the subject of future studies to
characterize its mass, atmosphere, and spin-orbit (mis)alignment, as
well as investigate the possibility of additional planets in the system.
Related projects
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
Enric
Pallé Bago