Issue |
A&A
Volume 602, June 2017
|
|
---|---|---|
Article Number | L8 | |
Number of page(s) | 5 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361/201731044 | |
Published online | 13 June 2017 |
Three planets around HD 27894
A close-in pair with a 2:1 period ratio and an eccentric Jovian planet at 5.4 AU⋆
1 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117, Heidelberg, Germany
e-mail: trifonov@mpia.de
2 Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
3 Main Astronomical Observatory, National Academy of Sciences of the Ukraine, Ukraine
4 Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany
5 Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
6 Department of Physics, The University of Hong Kong, Pokfulman Road, Hong Kong
7 European Southern Observatory (ESO), Alonso de Cordova 3107, Vitacura, Santiago de Chile, Chile
8 UCO/Lick Observatory, University of California, Santa Cruz, CA, 95064, USA
Received: 25 April 2017
Accepted: 30 May 2017
Aims. Our new program with HARPS aims to detect mean motion resonant planetary systems around stars which were previously reported to have a single bona fide planet, often based only on sparse radial velocity data.
Methods. Archival and new HARPS radial velocities for the K2V star HD 27894 were combined and fitted with a three-planet self-consistent dynamical model. The best-fit orbit was tested for long-term stability.
Results. We find clear evidence that HD 27894 is hosting at least three massive planets. In addition to the already known Jovian planet with a period Pb≈ 18 days we discover a Saturn-mass planet with Pc≈ 36 days, likely in a 2:1 mean motion resonance with the first planet, and a cold massive planet (≈5.3 MJup) with a period Pd ≈ 5170 days on a moderately eccentric orbit (ed = 0.39).
Conclusions. HD 27894 is hosting a massive, eccentric giant planet orbiting around a tightly packed inner pair of massive planets likely involved in an asymmetric 2:1 mean motion resonance. HD 27894 may be an important milestone for probing planetary formation and evolution scenarios.
Key words: techniques: radial velocities / planetary systems / planets and satellites: dynamical evolution and stability
© ESO, 2017
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.