Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planets
Creators: name: Christiansen, Jessie L.
name: Vanderburg, Andrew
name: Burt, Jennifer
name: Fulton, B. J.
name: Batygin, Konstantin
name: Benneke, Björn
name: Brewer, John M.
name: Charbonneau, David
name: Ciardi, David R.
name: Cameron, Andrew Collier
name: Coughlin, Jeffrey L.
name: Crossfield, Ian J. M.
name: Dressing, Courtney
name: Greene, Thomas P.
name: Howard, Andrew W.
name: Latham, David W.
name: Molinari, Emilio
name: Mortier, Annelies
name: Mullally, Fergal
name: Pepe, Francesco
name: Rice, Ken
name: Sinukoff, Evan
name: Sozzetti, Alessandro
name: Thompson, Susan E.
name: Udry, Stéphane
name: Vogt, Steven S.
name: Barman, Travis S.
name: Batalha, Natasha E.
name: Bouchy, Francois
name: Buchhave, Lars A.
name: Butler, R. Paul
name: Cosentino, Rosario
name: Dupuy, Trent J.
name: Ehrenreich, David
name: Fiorenzano, Aldo
name: Hansen, Brad M. S.
name: Henning, Thomas
name: Hirsch, Lea
name: Holden, Bradford P.
name: Isaacson, Howard T.
name: Johnson, John A.
name: Knutson, Heather A.
name: Kosiarek, Molly
name: López-Morales, Mercedes
name: Lovis, Christophe
name: Malavolta, Luca
name: Mayor, Michel
name: Micela, Giuseppina
name: Motalebi, Fatemeh
name: Petigura, Erik
name: Phillips, David F.
name: Piotto, Giampaolo
name: Rogers, Leslie A.
name: Sasselov, Dimitar
name: Schlieder, Joshua E.
name: Ségransan, Damien
name: Watson, Christopher A.
name: Weiss, Lauren M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: HD 3167 is a bright (V = 8.9), nearby K0 star observed by the NASA K2 mission (EPIC 220383386), hosting two small, short-period transiting planets. Here we present the results of a multi-site, multi-instrument radial velocity campaign to characterize the HD 3167 system. The masses of the transiting planets are 5.02+/-0.38 MEarth for HD 3167 b, a hot super-Earth with a likely rocky composition (rho_b = 5.60+2.15-1.43 g/cm^3), and 9.80+1.30-1.24 MEarth for HD 3167 c, a warm sub-Neptune with a likely substantial volatile complement (rho_c = 1.97+0.94-0.59 g/cm^3). We explore the possibility of atmospheric composition analysis and determine that planet c is amenable to transmission spectroscopy measurements, and planet b is a potential thermal emission target. We detect a third, non-transiting planet, HD 3167 d, with a period of 8.509+/-0.045 d (between planets b and c) and a minimum mass of 6.90+/-0.71 MEarth. We are able to constrain the mutual inclination of planet d with planets b and c: we rule out mutual inclinations below 1.3 degrees as we do not observe transits of planet d. From 1.3-40 degrees, there are viewing geometries invoking special nodal configurations which result in planet d not transiting some fraction of the time. From 40-60 degrees, Kozai-Lidov oscillations increase the system's instability, but it can remain stable for up to 100Myr. Above 60 degrees, the system is unstable. HD 3167 promises to be a fruitful system for further study and a preview of the many exciting systems expected from the upcoming NASA TESS mission.
description: 22 pages, 14 figures, 5 tables. Submitted to AJ March 3rd, 2017. Accepted April 28th, 2017. In press