Mahmoudreza Oshagh

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Understanding the activity-induced radial velocity jitter using space-based K2 photometry and HARPS RV observations

Dr. Mahmoudreza Oshagh

Post-doctoral research fellow, Institute for Astrophysics, Georg-August-University of Göttingen, Germany)

Host institution: Institute of Astrophysics and Space Sciences (IA), Porto, Portugal

Period: 18-04-2016 to 30-04-2016

Radial velocity measurements is one of the best and the most successful method in detecting extra-solar planets. The main objective of our study is to understand the stellar activity induced noise in the radial velocity (RV) measurements by using simultaneous photometric observations. This is of prime importance to mitigate the RV signal induced by stellar activity and therefore unveil the presence of low-mass exoplanets (down to the Earth-mass planet regime).

In order to do that we obtained simultaneous high-precision photometric observations (using K2 space telescope) and high-precision RV measurements (using HARPS spectrograph on 3.6 meter telescope of ESO, Chile) of twelve active stars. During my visit to IA-Porto, we reduced the photometric observation of K2 (by using the pipeline developed by Dr. Susana Barros) and also reduced the spectra obtained by HAPRS spectrograph (wit the help of Prof. Nuno Santos and Dr. Pedro Figueira and using the Geneva Observatory pipeline). Then we performed a detailed analysis of our simultaneous photometric modulation and RV variation and tried to establish possible correlation between them. This correlation can be used in order to estimate the activity induced RV signal, and therefore remove that signal from RV measurements, to be able to retrieve the signal of low-mass exoplanets.

The results of our analysis will be published soon in the Astronomy & Astrophysics journal.







CSO Approval date: 14/11/2013
Starting date: 15/05/2014
Ending date: 14/05/2018

Action Chair:
Dr. Muriel GARGAUD (FR)

Vice chair:
Prof. Wolf GEPPERT (SE)

STSM Manager:
Prof. Nigel MASON (UK)

Web Manager:



Grant Holder Financial Representative:

Mrs Annick Caperan

Science Officer:
Dr. Mafalda QUINTAS

Administrative Officer:
Ms Ange Marie Ina Uwase



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COST is supported by the EU Framework Programme Horizon 2020



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