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

• Autor(a) principal: Brucalassi, A.
• Data de Publicação: 2016
• Outros Autores: Pasquini, v, Saglia, R., Ruiz, M. T., Bonifacio, v, Leão, I., Martins, B. L. Canto, Medeiros, José Renan de, Bedin, L. R., Biazzo, v, Melo, C., Lovis, C., Randich, S.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/jspui/handle/123456789/29089; https://doi.org/10.1051/0004-6361/201527561
• topic: Planets and satellites: gaseous planets; Techniques: radial velocities

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+5.4-2.6% for single stars and 4.5%+4.5-2.5% 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.