Search for giant planets in M67: III. Excess of hot Jupiters in dense open clusters

Journal
Date Issued
2016
Author(s)
•
Pasquini, L.
•
Saglia, R.
•
Ruiz, M.T.
•
Bonifacio, P
•
Leão, I.
•
Canto Martins, B.L.
•
De Medeiros, J.R.
•
•
•
Melo, C.
•
Lovis, C.
•
DOI
Abstract
Since 2008 we used high-precision radial velocity (RV) measurements obtained with different telescopes to detect signatures of massive planets around main-sequence and evolved stars of the open cluster (OC) M67. We aimed to perform a long-term study on giant planet formation in open clusters and determine how this formation depends on stellar mass and chemical composition. A new hot Jupiter (HJ) around the main-sequence star YBP401 is reported in this work. An update of the RV measurements for the two HJ host-stars YBP1194 and YBP1514 is also discussed. Our sample of 66 main-sequence and turnoff stars includes 3 HJs, which indicates a high rate of HJs in this cluster (5.6% for single stars and 4.5% for the full sample). This rate is much higher than what has been discovered in the field, either with RV surveys or by transits. High metallicity is not a cause for the excess of HJs in M67, nor can the excess be attributed to high stellar masses. When combining this rate with the non-zero eccentricity of the orbits, our results are qualitatively consistent with a HJ formation scenario dominated by strong encounters with other stars or binary companions and subsequent planet-planet scattering, as predicted by N-body simulations.
Volume
592
Start page
L1
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2016A&A...590A..78B
Rights
open.access
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