Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-24T11:57:30.724Z Has data issue: false hasContentIssue false
  • English
  • Français

Stellar noise and planet detection. I. Oscillations, granulation and sun-like spots

Published online by Cambridge University Press:  10 November 2011

Xavier Dumusque ,
Nuno C. Santos ,
Stéphane Udry ,
Cristophe Lovis  and
Xavier Bonfils
Xavier Dumusque
Affiliation:
Observatoire de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland email: [email protected] Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
Nuno C. Santos
Affiliation:
Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
Stéphane Udry
Affiliation:
Observatoire de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland email: [email protected]
Cristophe Lovis
Affiliation:
Observatoire de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland email: [email protected]
Xavier Bonfils
Affiliation:
Université J. Fourier (Grenoble 1)/CNRS, Laboratoire d'Astrophysique de Grenoble, France
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Spectrographs like HARPS can now reach a sub-ms−1 precision in radial-velocity (RV) (Pepe & Lovis 2008). At this level of accuracy, we start to be confronted with stellar noise produced by 3 different physical phenomena: oscillations, granulation phenomena (granulation, meso- and super-granulation) and activity. On solar type stars, these 3 types of perturbation can induce ms−1 RV variation, but on different time scales: 3 to 15 minutes for oscillations, 15 minutes to 1.5 days for granulation phenomena and 10 to 50 days for activity. The high precision observational strategy used on HARPS, 1 measure per night of 15 minutes, on 10 consecutive days each month, is optimized, due to a long exposure time, to average out the noise coming from oscillations (Dumusque et al. 2011a) but not to reduce the noise coming from granulation and activity (Dumusque et al. 2011a and Dumusque et al. 2011b). The smallest planets found with this strategy (Mayor et al. 2009) seems to be at the limit of the actual observational strategy and not at the limit of the instrumental precision. To be able to find Earth mass planets in the habitable zone of solar-type stars (200 days for a K0 dwarf), new observational strategies, averaging out simultaneously all type of stellar noise, are required.

Keywords

planetary systemsstars: activitystars: oscillationsstars: spotstechniques: radial velocities
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S276: The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution , October 2010 , pp. 527 - 529
Copyright
Copyright © International Astronomical Union 2011

References

Dumusque, X., et al. 2011a, A&A, 525, A140Google Scholar
Dumusque, X., et al. 2011b, A&A, 527, A82Google Scholar
Lefebvre, S., et al. 1984, A&A, 490, 1143Google Scholar
Mayor, M. et al. 2009, A&A, 507, 487Google Scholar
Pepe, F. & Lovis, C. 2008, Physica Scripta, 130Google Scholar