M2K. II. A Triple-Planet System Orbiting Hip 57274
2012 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 745, no 1, 21- p.Article in journal (Refereed) Published
Doppler observations from Keck Observatory have revealed a triple-planet system orbiting the nearby K4V star, HIP 57274. The inner planet, HIP 57274b, is a super-Earth with M sin i = 11.6 M-circle plus (0.036 M-Jup), an orbital period of 8.135 +/- 0.004 days, and slightly eccentric orbit e = 0.19 +/- 0.1. We calculate a transit probability of 6.5% for the inner planet. The second planet has M sin i = 0.4 M-Jup with an orbital period of 32.0 +/- 0.02 days in a nearly circular orbit (e = 0.05 +/- 0.03). The third planet has M sin i = 0.53 M-Jup with an orbital period of 432 +/- 8 days (1.18 years) and an eccentricity e = 0.23 +/- 0.03. This discovery adds to the number of super-Earth mass planets with M sin i < 12 M-circle plus that have been detected with Doppler surveys. We find that 56% +/- 18% of super-Earths are members of multi-planet systems. This is certainly a lower limit because of observational detectability limits, yet significantly higher than the fraction of Jupiter mass exoplanets, 20% +/- 8%, that are members of Doppler-detected, multi-planet systems.
Place, publisher, year, edition, pages
2012. Vol. 745, no 1, 21- p.
planetary systems, stars: individual (HIP 57274)
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:uu:diva-172068DOI: 10.1088/0004-637X/745/1/21ISI: 000300316600021OAI: oai:DiVA.org:uu-172068DiVA: diva2:513311