Very precise radial velocities with high-resolution spectrographs

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• Xavier Dumusque (CfA)
• Wednesday 12 November 2014, 16:30-17:30
• Martin Ryle Seminar Room, Kavli Institute.

If you have a question about this talk, please contact Dr B.-O. Demory.

I will first discuss a new technique to derive extremely precise radial velocities (RV) from high-resolution spectrographs. By deriving the RV of each individual line in a HARPS spectrum, one can see that some spectral lines are affected by important variations that cannot be associated to planetary or stellar signals. These variation are caused by the instrument itself, and excluding the affected spectral lines when cross correlating the stellar spectrum with a synthetic template can improve the RV precision. In a second part, I will present a new model that estimates the effect of stellar activity on RV measurements. This model, based on observations of the Sun, includes the inhibition of convection which is one of the main cause of the activity-induced RV variation. When comparing with observations, our model reproduces the activity-related variation seen in photometry, RV, bisector and full width of half maximum. This model can therefore be used to fit observed data, which gives us access to interesting stellar parameters like stellar inclination.

This talk is part of the Exoplanet Seminars series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Exoplanet Seminars
• Institute of Astronomy Talk Lists
• LCLU Departmental Talks
• Martin Ryle Seminar Room, Kavli Institute

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