Title: Two 'b's in the Beehive: The Discovery of the First Hot Jupiters in an Open Cluster Authors: S. N. Quinn (1), R. J. White (1), D. W. Latham (2), L. A. Buchhave (3 and 4), J. R. Cantrell (1), S. E. Dahm (5), G. Fürész (2), A. H. Szentgyorgyi (2), J. C. Geary (2), G. Torres (2), A. Bieryla (2), P. Berlind (2), M. C. Calkins (2), G. A. Esquerdo (2), R. P. Stefanik (2) ((1) Georgia State University, (2) Harvard-Smithsonian Center for Astrophysics, (3) Niels Bohr Institute, University of Copenhagen, (4) Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, (5) W. M. Keck Observatory)
We present the discovery of two giant planets orbiting stars in Praesepe (also known as the Beehive Cluster), the first known hot Jupiters in an open cluster. Pr0201b orbits a V=10.52 late F dwarf with a period of 4.4264 ±0.0070 days and has a minimum mass of 0.540 ±0.039 Jupiter masses, and Pr0211b orbits a V=12.06 late G dwarf with a period of 2.1451 ±0.0012 days and has a minimum mass of 1.844 ±0.064 Jupiter masses. Because they reside in a cluster, the ages of these planets are amongst the best-determined of any planet outside our own solar system. As we endeavour to learn more about the frequency and characteristics of planets, the environment in which most stars form -- open clusters like Praesepe -- may provide essential clues to this end. This discovery will allow, for the first time, a direct estimate of the short-period giant planet frequency in open clusters.