Acne at The Bottom Of The Main Sequence
Abstract
Starspots are an important manifestation of stellar activity and yet their distribution patterns on the lowest mass stars is not well known. Time series spectra of fully convective M dwarfs taken in the red-optical with UVES reveal numerous line profile distortions which are interpreted as starspots. We derive Doppler images for four M4.5V - M9V stars and find that contrast ratios corresponding to photosphere-spot temperature differences of only 200-300 K are sufficient to model the timeseries spectra. Although more starspot structure is found at high latitudes, spots are reconstructed at a range of phases and latitudes with mean spot filling factors of only a few per cent. The occurrence of low-contrast spots at predominantly high latitudes is in general likely to be responsible for the low amplitude photometric variability seen in late-M dwarfs. The recovered starspot patterns are used to assess their effect on precision radial velocity surveys aimed at detecting planets around this population of stars.
- Publication:
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19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun (CS19)
- Pub Date:
- August 2016
- DOI:
- 10.5281/zenodo.154526
- Bibcode:
- 2016csss.confE..10B
- Keywords:
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- Zenodo community cs19