Low-gravity L Dwarfs Are Likely More Variable

Stanimir Metchev, Aren Heinze, Daniel Apai, Davin Flateau, Jacqueline Radigan, Adam Burgasser, Mark Marley, Étienne Artigau, Peter Plavchan, Bertrand Goldman

Research output: Contribution to journalArticlepeer-review


In the Weather on Other Worlds Spitzer Exploration Science program, we surveyed 44 nearby L3-T8 dwarfs for spot-induced rotational variability. Among single L3-L9.5 dwarfs, we found that 80% are variable at >0.2% in the 3-5 μm wavelength range, while 36% of T0-T8 were variable at >0.4%. Taking into account viewing angle and sensitivity considerations, both of these findings are consistent with spots being present on ∼100% of L3-T8 dwarfs. Intriguingly, we find a tentative association (92% confidence) between low surface gravity and high-amplitude variability among L3-L5.5 dwarfs. Although we can not confirm whether lower gravity is also correlated with a higher incidence of variables, the result is promising for the characterization of directly imaged young extrasolar planets through variability.

Original languageEnglish (US)
Pages (from-to)121-123
Number of pages3
JournalProceedings of the International Astronomical Union
StatePublished - 2015


  • brown dwarfs
  • stars: low-mass
  • stars: starspots
  • stars: variables: general
  • stars:rotation
  • techniques: photometric

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


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