The K2-ESPRINT Project IV. A Hot Jupiter in a Prograde Orbit with a Possible Stellar Companion

Hirano, T.; Nowak, G.; Kuzuhara, M.; Palle, E.; Dai, Fei; Yu, Liang; Van Eylen, Vincent; Takeda, Yoichi; Brandt, Timothy D.; Narita, Norio; Velasco, S.; Prieto Arranz, J.; Sanchis-Ojeda, Roberto; Winn, Joshua N.; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Fukui, Akihiko; Sato, Bun’ei; Albrecht, Simon; Ribas, Ignasi; Ryu, Tsuguru; Tamura, Motohide
Bibliographical reference

The Astrophysical Journal, Volume 825, Issue 1, article id. 53, pp. (2016).

Advertised on:
7
2016
Number of authors
22
IAC number of authors
4
Citations
24
Refereed citations
22
Description
We report on the detection and early characterization of a hot Jupiter in a three day orbit around K2-34 (EPIC 212110888), a metal-rich F-type star located in the K2 Cycle 5 field. Our follow-up campaign involves precise radial velocity (RV) measurements and high-contrast imaging using multiple facilities. The absence of a bright nearby source in our high-contrast data suggests that the transit-like signals are not due to light variations from such a companion star. Our intensive RV measurements show that K2-34b (EPIC 212110888b) has a mass of 1.773+/- 0.086{M}J, confirming its status as a planet. We also detect the Rossiter–McLaughlin effect for K2-34b and show that the system has a good spin–orbit alignment (λ = -{1}-9+10 degrees). High-contrast images obtained by the HiCIAO camera on the Subaru 8.2 m telescope reveal a faint companion candidate (CC) ({{Δ }}{m}H\=\6.19+/- 0.11 mag) at a separation of 0\buildrel{\prime\prime}\over{.} 36. Follow-up observations are needed to confirm that the CC is physically associated with K2-34. K2-34b appears to be an example of a typical “hot Jupiter,” albeit one which can be precisely characterized using a combination of K2 photometry and ground-based follow-up.