Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

The HARPS search for Earth-like planets in the habitable zone
I - Very low-mass planets around HD20794, HD85512 and HD192310

F. Pepe, C. Lovis, D. Ségransan, W. Benz, F. Bouchy, X. Dumusque, M. Mayor, D. Queloz, N. C. Santos, S. Udry

Abstract
Context.In 2009 we started an intense radial-velocity monitoring of a few nearby, slowly-rotating and quiet solar-type stars within the dedicated HARPS-Upgrade GTO program.

Aims. The goal of this campaign is to gather very-precise radial-velocity data with high cadence and continuity to detect tiny signatures of very-low-mass stars that are potentially present in the habitable zone of their parent stars.

Methods. Ten stars were selected among the most stable stars of the original HARPS high-precision program that are uniformly spread in hour angle, such that three to four of them are observable at any time of the year. For each star we recorded 50 data points spread over the observing season. The data points consist of three nightly observations with a total integration time of 10 min each and are separated by two hours. This is an observational strategy adopted to minimize stellar pulsation and granulation noise.

Results. We present the first results of this ambitious program. The radial-velocity data and the orbital parameters of five new and one confirmed low-mass planets around the stars HD20794, HD85512, and HD192310 are reported and discussed, among which is a system of three super-Earths and one that harbors a 3.6 M-planet at the inner edge of the habitable zone.

Conclusions. This result already confirms previous indications that low-mass planets seem to be very frequent around solar-type stars and that this may occur with a frequency higher than 30%.

Keywords
planetary systems - instrumentation: spectrographs - techniques: radial velocities - stars: individual: HD20794 - stars: individual: HD85512 - stars: individual: HD192310

Notes
Based on observations made with the HARPS instrument on ESO’s 3.6m telescope at the La Silla Observatory in the frame of the HARPS Upgrade GTO program ID 086.C-0230.
Tables 7–9 (RV data) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A58

Astronomy and Astrophysics
Volume 534, Page A58_1
October 2011

>> ADS>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website