Three’s Company: An Additional Non-transiting Super-Earth in the Bright HD 3167 System, and Masses for All Three Planets

Jessie L. Christiansen, Andrew Vanderburg, Jennifer Burt, B. J. Fulton, Konstantin Batygin, Björn Benneke, John M. Brewer, David Charbonneau, David R. Ciardi, Andrew Collier Cameron, Jeffrey L. Coughlin, Ian J. M. Crossfield, Courtney Dressing, Thomas P. Greene, Andrew W. Howard, David W. Latham, Emilio Molinari, Annelies Mortier, Fergal Mullally, Francesco PepeKen Rice, Evan Sinukoff, Alessandro Sozzetti, Susan E. Thompson, Stéphane Udry, Steven S. Vogt, Travis S. Barman, Natasha E. Batalha, François Bouchy, Lars A. Buchhave, R. Paul Butler, Rosario Cosentino, Trent J. Dupuy, David Ehrenreich, Aldo Fiorenzano, Brad M. S. Hansen, Thomas Henning, Lea Hirsch, Bradford P. Holden, Howard T. Isaacson, John A. Johnson, Heather A. Knutson, Molly Kosiarek, Mercedes López-Morales, Christophe Lovis, Luca Malavolta, Michel Mayor, Giuseppina Micela, Fatemeh Motalebi, Erik Petigura, David F. Phillips, Giampaolo Piotto, Leslie A. Rogers, Dimitar Sasselov, Joshua E. Schlieder, Damien Ségransan, Christopher A. Watson, Lauren M. Weiss

Research output: Contribution to journalArticlepeer-review


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 {M}\oplus for HD 3167 b, a hot super-Earth with a likely rocky composition ({ρ }b = {5.60}-1.43+2.15 g cm‑3), and {9.80}-1.24+1.30 {M}\oplus for HD 3167 c, a warm sub-Neptune with a likely substantial volatile complement ({ρ }c = {1.97}-0.59+0.94 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 {M}\oplus . We are able to constrain the mutual inclination of planet d with planets b and c: we rule out mutual inclinations below 1.°3 because we do not observe transits of planet d. From 1.°3 to 40°, there are viewing geometries invoking special nodal configurations, which result in planet d not transiting some fraction of the time. From 40° to 60°, Kozai–Lidov oscillations increase the system’s instability, but it can remain stable for up to 100 Myr. Above 60°, 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.
Original languageEnglish
Pages (from-to)122
JournalAstronomical Journal
Issue number3
Publication statusPublished - 31 Aug 2017


  • eclipses
  • stars: individual: HD 3167
  • techniques: photometric
  • techniques: spectroscopic


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