Letter to the Editor

Hot-Jupiters and hot-Neptunes: A common origin?

¹ CRAL (UMR 5574 CNRS), École Normale Supérieure, 69364 Lyon Cedex 07, France e-mail: [ibaraffe;chabrier;fselsis;fallard]@ens-lyon.fr
² International Space Science Institute, Hallerstr. 6, 3012, Bern, Switzerland
³ Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095, USA e-mail: barman@astro.ucla.edu
⁴ Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: yeti@hs.uni-hamburg.de

Received: 11 March 2005
Accepted: 9 May 2005

Abstract

We compare evolutionary models for close-in exoplanets coupling irradiation and evaporation due respectively to the thermal and high energy flux of the parent star with observations of recently discovered new transiting planets. The models provide an overall good agreement with observations, although at the very limit of the quoted error bars of OGLE-TR-10, depending on its age. Using the same general theory, we show that the three recently detected hot-Neptune planets (GJ436, ρ  Cancri, μ Ara) may originate from more massive gas giants which have undergone significant evaporation. We thus suggest that hot-Neptunes and hot-Jupiters may share the same origin and evolution history. Our scenario provides testable predictions in terms of the mass-radius relationships of these hot-Neptunes.