Skip to main content Accessibility help
×
Home

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

  • Christoph Bergmann (a1), Michael Endl (a2), John B. Hearnshaw (a1), Robert A. Wittenmyer (a3) and Duncan J. Wright (a3)...

Abstract

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 m s−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.

Copyright

Corresponding author

References

Hide All
Borucki, W.J. et al. (2010). Science 327, 977.
Dumusque, X. et al. (2012). Nature 491, 207.
Eggenberger, A., Udry, S., Mazeh, T., Segal, Y. & Mayor, M. (2007). Astron. Astrophys. 466, 1179.
Endl, M., Kürster, M. & Els, S. (2000). Astron. Astrophys. 362, 585.
Endl, M., Bergmann, C., Hearnshaw, J., Barnes, S.I., Wittenmyer, R.A., Ramm, D., Kilmartin, P., Gunn, F. & Brogt, E. (2014). Int. J. Astrobiol, doi: http://dx.doi.org/10.1017/S1473550414000081.
Fekel, F.C. Jr. & Beavers, W.I. (1983). Astrophys. J. 267, 682.
Hatzes, A.P. (2013). Astrophys. J. 770, 133.
Hearnshaw, J.B., Barnes, S.I., Kershaw, G.M., Frost, N., Graham, G., Ritchie, R. & Nankivell, G.R. (2002). Exp. Astron. 13, 59.
Hearnshaw, J., Barnes, S., Endl, M. & Wittenmyer, R. (2013). Planets in the Solar System and beyond. In Proc. of the 11th Asian-Pacific Regional IAU Meeting, National Astronomical Research Institute of Thailand, Thailand.
Jenkins, J.S. & Tuomi, M. (2014). arXiv:1406.3093.
Kaltenegger, L. & Haghighipour, N. (2013). Astrophys. J. 777, 165.
Konacki, M. (2005). Nature 436, 230.
Konacki, M., Muterspaugh, M.W., Kulkarni, S.R. & Hełminiak, K.G. (2009). Astrophys. J. 704, 513.
Mayor, M. & Queloz, D. (1995). Nature 378, 355.
Mayor, M. et al. (2003). The Messenger 114, 20.
Pourbaix, D. et al. (2002). Astron. Astrophys. 386, 280.
Quintana, E.V. et al. (2014). Science 344, 277.
Ratajczak, M., Konacki, M., Kulkarni, S.R. & Muterspaugh, M.W. (2012). From interacting binaries to exoplanets: essential modeling tools. In Proc. of the IAU Symp. 282, Cambridge University Press, UK.
Tuomi, M. et al. (2013). Astron. Astrophys. 551, A79.
Wang, S.X. et al. (2012). Astrophys. J. 761, 46.
Wittenmyer, R.A., Endl, M., Bergmann, C., Hearnshaw, J., Barnes, S.I. & Wright, D. (2014). Formation, detection, and characterization of extrasolar habitable planets. In Proc. of the IAU Symp. 293, Cambridge University Press, UK.
Wright, J.T. & Howard, A.W. (2009). Astrophys. J. Suppl. 182, 205.
Wright, J.T. & Howard, A.W. (2013). Astrophys. J. Suppl. 205, 22.

Keywords

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed