Astron. Astrophys. 344, L5-L8 (1999)

Letter to the Editor

Precise radial velocities of Proxima Centauri ^*

Strong constraints on a substellar companion

M. Kürster ¹, A.P. Hatzes ², W.D. Cochran ², S. Döbereiner ³, K. Dennerl ³ and M. Endl <sup>1,4

1</sup> European Southern Observatory, Casilla 19001, Vitacura, Santiago 19, Chile
² McDonald Observatory, The University of Texas at Austin, Austin, TX 78712-1083, USA
³ Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany
⁴ Institut für Astronomie, Universität Wien, Türkenschanzstrasse 17, A-1180 Wien, Austria

Received 20 January 1999 / Accepted 18 February 1999

Abstract

We present differential radial velocity measurements of Proxima Centauri collected over 4 years with the ESO CES with a mean precision of . We find no evidence of a periodic signal that could corroborate the existence of a sub-stellar companion. We put upper limits (97% confidence) to the companion mass ranging from 1.1 to at orbital periods of 0.75 to 3000 d, i.e. separations  AU from Prox Cen. Our mass limits concur with limits found by precise astrometry (Benedict et al. 1998a and priv. comm.) which strongly constrain the period range  d to . Combining both results we exclude a brown dwarf or supermassive planet at separations  AU from Prox Cen. We also find that, at the level of our precision, the RV data are not affected by stellar activity.

Key words: stars: planetary systems stars: individual: Prox Cen stars: rotation techniques: radial velocities

* Based on observations collected at the European Southern Observatory, La Silla

Send offprint requests to: M. Kürster (mkurster@eso.org)

SIMBAD Objects

Contents

• 1. Introduction
• 2. The planet search program at the ESO CES
• 3. The RV measurements for Proxima Cen
• 4. Period search
• 5. Limits to companion parameters
• 6. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: March 10, 1999
helpdesk.link@springer.de