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An exoplanet in orbit around tau^1 Gruis

Hugh R. A. Jones·R. Paul Butler·Chris G. Tinney·Geoff W. Marcy·Alan J. Penny·Chris McCarthy·Brad D. Carter
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Abstract

We report the detection of a new candidate exoplanet around the metal-rich star tau^1 Gruis. With M sin $i$ = 1.23+/-0.18 M_JUP, a period of 1326+/-300 d and an orbit with an eccentricity of 0.14+/-0.14 it adds to the growing population of long period exoplanets with near-circular orbits. This population now comprises more than 20% of known exoplanets. When the companion to tau^1 Gruis is plotted together with all exoplanets found by the Anglo-Australian Planet Search and other radial velocity searches we find evidence for a peak in the number of short-period exoplanets, followed by a minimum of planets between around 7 and 50 days and then an apparent rise in the number of planets per unit radius that seems to set in by a hundred days, indicating more planets farther from the host star. This is very different from the gaussian-like period distribution found for stellar companions. This lends support to the idea that once a clearing in the inner protoplanetary disk develops, it halts the inward migration of planets. In particular, the smooth distribution of exoplanets arising from planetary migration through a disk is altered by an accumulation of exoplanets at the point where the disk has been cleared out.

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Hugh R. A. Jones, R. Paul Butler, Chris G. Tinney, Geoff W. Marcy, Alan J. Penny, Chris McCarthy, Brad D. Carter. 2002-09-16. An exoplanet in orbit around tau^1 Gruis. https://doi.org/10.1046/j.1365-8711.2003.06481.x

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