Rotational modulation of M/L dwarfs due to magnetic spots

C. Lane, G. Hallinan, R. T. Zavala, R. F. Butler, R. P. Boyle, S. Bourke, A. Antonova, J. G. Doyle, F. J. Vrba, A. Golden

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

We find periodic I-band variability in two ultracool dwarfs, TVLM 513-46546 and 2MASS J00361617+1821104, on either side of the M/L dwarf boundary. Both of these targets are short-period radio transients, with the detected I-band periods matching those found at radio wavelengths (P = 1.96 hr for TVLM 513-46546 and P = 3 hr for 2MASS J00361617 + 1821104). We attribute the detected I-band periodicities to the periods of rotation of the dwarfs, supported by radius estimates and measured values for the objects. Based on the detected period of rotation of TVLM 513-46546 (M9) in the I band, along with confirmation of strong magnetic fields from recent radio observations, we argue for magnetically induced spots as the cause of this periodic variability. The I-band rotational modulation of the L3.5 dwarf 2MASS J00361617 + 1821104 appeared to vary in amplitude with time. We conclude that the most likely cause of the I-band variability for this object is magnetic spots, possibly coupled with time-evolving features such as dust clouds.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume668
Issue number2 PART 2
DOIs
StatePublished - 2007
Externally publishedYes

Fingerprint

radio
modulation
periodicity
dust
magnetic field
wavelength
radio observation
causes
periodic variations
radii
estimates
magnetic fields
wavelengths

Keywords

  • Brown dwarfs
  • Methods: data analysis
  • Stars: low-mass
  • Stars: rotation
  • Stars: spots
  • Stars: variables: other
  • Techniques: photometric

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Lane, C., Hallinan, G., Zavala, R. T., Butler, R. F., Boyle, R. P., Bourke, S., ... Golden, A. (2007). Rotational modulation of M/L dwarfs due to magnetic spots. Astrophysical Journal, 668(2 PART 2). https://doi.org/10.1086/523041

Rotational modulation of M/L dwarfs due to magnetic spots. / Lane, C.; Hallinan, G.; Zavala, R. T.; Butler, R. F.; Boyle, R. P.; Bourke, S.; Antonova, A.; Doyle, J. G.; Vrba, F. J.; Golden, A.

In: Astrophysical Journal, Vol. 668, No. 2 PART 2, 2007.

Research output: Contribution to journalArticle

Lane, C, Hallinan, G, Zavala, RT, Butler, RF, Boyle, RP, Bourke, S, Antonova, A, Doyle, JG, Vrba, FJ & Golden, A 2007, 'Rotational modulation of M/L dwarfs due to magnetic spots', Astrophysical Journal, vol. 668, no. 2 PART 2. https://doi.org/10.1086/523041
Lane C, Hallinan G, Zavala RT, Butler RF, Boyle RP, Bourke S et al. Rotational modulation of M/L dwarfs due to magnetic spots. Astrophysical Journal. 2007;668(2 PART 2). https://doi.org/10.1086/523041
Lane, C. ; Hallinan, G. ; Zavala, R. T. ; Butler, R. F. ; Boyle, R. P. ; Bourke, S. ; Antonova, A. ; Doyle, J. G. ; Vrba, F. J. ; Golden, A. / Rotational modulation of M/L dwarfs due to magnetic spots. In: Astrophysical Journal. 2007 ; Vol. 668, No. 2 PART 2.
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AU - Hallinan, G.

AU - Zavala, R. T.

AU - Butler, R. F.

AU - Boyle, R. P.

AU - Bourke, S.

AU - Antonova, A.

AU - Doyle, J. G.

AU - Vrba, F. J.

AU - Golden, A.

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AB - We find periodic I-band variability in two ultracool dwarfs, TVLM 513-46546 and 2MASS J00361617+1821104, on either side of the M/L dwarf boundary. Both of these targets are short-period radio transients, with the detected I-band periods matching those found at radio wavelengths (P = 1.96 hr for TVLM 513-46546 and P = 3 hr for 2MASS J00361617 + 1821104). We attribute the detected I-band periodicities to the periods of rotation of the dwarfs, supported by radius estimates and measured values for the objects. Based on the detected period of rotation of TVLM 513-46546 (M9) in the I band, along with confirmation of strong magnetic fields from recent radio observations, we argue for magnetically induced spots as the cause of this periodic variability. The I-band rotational modulation of the L3.5 dwarf 2MASS J00361617 + 1821104 appeared to vary in amplitude with time. We conclude that the most likely cause of the I-band variability for this object is magnetic spots, possibly coupled with time-evolving features such as dust clouds.

KW - Brown dwarfs

KW - Methods: data analysis

KW - Stars: low-mass

KW - Stars: rotation

KW - Stars: spots

KW - Stars: variables: other

KW - Techniques: photometric

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