Finding exoplanets orbiting young active stars - I. Technique

V. E. Moulds*, C. A. Watson, X. Bonfils, S. P. Littlefair, E. K. Simpson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
199 Downloads (Pure)

Abstract

Stellar activity, such as starspots, can induce radial velocity (RV) variations that can mask or even mimic the RV signature of orbiting exoplanets. For this reason RV exoplanet surveys have been unsuccessful when searching for planets around young, active stars and are therefore failing to explore an important regime which can help to reveal how planets form and migrate. This paper describes a new technique to remove spot signatures from the stellar line-profiles of moderately rotating, active stars (v sin i ranging from 10 to 50 km s(-1)). By doing so it allows planetary RV signals to be uncovered. We used simulated models of a G5V type star with differing dark spots on its surface along with archive data of the known active star HD 49933 to validate our method. The results showed that starspots could be effectively cleaned from the line-profiles so that the stellar RV jitter was reduced by more than 80 per cent. Applying this procedure to the same models and HD 49933 data, but with fake planets injected, enabled the effective removal of starspots so that Jupiter mass planets on short orbital periods were successfully recovered. These results show that this approach can be useful in the search for hot-Jupiter planets that orbit around young, active stars with a v sin i of similar to 10-50 km/s.

Original languageEnglish
Pages (from-to)1709-1721
JournalMonthly Notices of the Royal Astronomical Society
Volume430
Issue number3
DOIs
Publication statusPublished - 11 Feb 2013

Keywords

  • line: profiles
  • methods: data analysis
  • planets and satellites: detection
  • planets and satellites: general
  • stars: activity
  • starspots
  • BROWN DWARF DESERT
  • STELLAR ACTIVITY
  • MASSIVE PLANET
  • HOT-JUPITER
  • COOL STARS
  • BD+20 1790
  • SUN
  • SPOTS
  • VARIABILITY
  • PARAMETERS

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