We announce the discovery of a twin of Jupiter orbiting the slightly metal-poor ([Fe/H] = -0.1) nearby (d = 18 pc) G8 dwarf HD 154345. This planet has a minimum mass of 0.95 Jupiter masses and a 9.2 year, circular orbit with radius 4.2 AU. There is currently little or no evidence for other planets in the system, but smaller or exterior planets cannot yet be ruled out. We also detect a ~ 9-year activity cycle in this star photometrically and in chromospheric emission. We rule out activity cycles as the source of the radial velocity variations by comparison with other cycling late-G dwarfs.
@article{arxiv.0802.1731,
title = {The Jupiter Twin HD 154345b},
author = {J. T. Wright and G. W. Marcy and R. P. Butler and S. S. Vogt and G. W. Henry and H. Isaacson and A. W. Howard},
journal= {arXiv preprint arXiv:0802.1731},
year = {2009}
}
Comments
15pp. ApJL. v2: Substantial additions, including 3 new authors, new photometry, activity measurements, and a discussion of activity cycles