Weather on other worlds. I. Detection of periodic variability in the L3 dwarf DENIS-P J1058.7-1548 with precise multi-wavelength photometry

Aren N. Heinze, Stanimir Metchev, Daniel Apai, Davin Flateau, Radostin Kurtev, Mark Marley, Jacqueline Radigan, Adam J. Burgasser, Étienne Artigau, Peter Plavchan

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Photometric monitoring from warm Spitzer reveals that the L3 dwarf DENIS-P J1058.7-1548 varies sinusoidally in brightness with a period of hr and an amplitude of 0.388% ± 0.043% (peak-to-valley) in the 3.6 μm band, confirming the reality of a 4.31 ± 0.31 hr periodicity detected in J-band photometry from the SOAR telescope. The J-band variations are a factor of 2.17 ± 0.35 larger in amplitude than those at 3.6 μm, while 4.5 μm Spitzer observations yield a 4.5 μm/3.6 μm amplitude ratio of only 0.23 ± 0.15, consistent with zero 4.5 μm variability. This wide range in amplitudes indicates rotationally modulated variability due to magnetic phenomena and/or inhomogeneous cloud cover. Weak Hα emission indicates some magnetic activity, but it is difficult to explain the observed amplitudes by magnetic phenomena unless they are combined with cloud inhomogeneities (which might have a magnetic cause). However, inhomogeneous cloud cover alone can explain all our observations, and our data align with theory in requiring that the regions with the thickest clouds also have the lowest effective temperature. Combined with published vsin (i) results, our rotation period yields a 95% confidence lower limit of R * ≥ 0.111 R, suggesting upper limits of 320 Myr and 0.055 M on the age and mass. These limits should be regarded cautiously because of 3σ inconsistencies with other data; however, a lower limit of 45° on the inclination is more secure. DENIS-P J1058.7-1548 is only the first of nearly two dozen low-amplitude variables discovered and analyzed by the Weather on Other Worlds project.

Original languageEnglish (US)
Article number173
JournalAstrophysical Journal
Volume767
Issue number2
DOIs
StatePublished - Apr 20 2013

Keywords

  • brown dwarfs
  • stars: individual (DENIS-P J1058.7-1548)
  • stars: low-mass
  • stars: rotation
  • stars: variables: general
  • starspots
  • techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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