Searching for Earth-mass planets around α Centauri: precise radial velocities from contaminated spectra

Bergmann, Christoph and Endl, Michael and Hearnshaw, John B. and Wittenmyer, Robert A. and Wright, Duncan J. (2015) Searching for Earth-mass planets around α Centauri: precise radial velocities from contaminated spectra. International Journal of Astrobiology, 14 (2). pp. 173-176. ISSN 1473-5504


This work is part of an ongoing project which aims to detect terrestrial planets in our neighbouring star system α Centauri using the Doppler method. Owing to the small angular separation between the two components of the α Cen AB binary system, the observations will to some extent be contaminated with light coming from the other star. We are accurately determining the amount of contamination for every observation by measuring the relative strengths of the H-α and NaD lines. Furthermore, we have developed a modified version of a well-established Doppler code that is modelling the observations using two stellar templates simultaneously. With this method we can significantly reduce the scatter of the radial velocity (RV) measurements due to spectral cross-contamination and hence increase our chances of detecting the tiny signature caused by potential Earth-mass planets. After correcting for the contamination we achieve RV precision of ∼2.5 ms-1 for a given night of observations. We have also applied this new Doppler code to four southern double-lined spectroscopic binary systems (HR159, HR913, HR7578 and HD181958) and have successfully recovered radial velocities for both components simultaneously.

Statistics for USQ ePrint 31768
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version due to publisher copyright policy.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 19 May 2017 05:53
Last Modified: 08 Oct 2018 04:42
Uncontrolled Keywords: data analysis; HR7578; planetary systems; radial velocities; spectroscopic binaries; α Centauri;
Fields of Research (2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI:

Actions (login required)

View Item Archive Repository Staff Only