Kepler Monitoring of an L Dwarf I. The Photometric Period and White Light Flares

DSpace/Manakin Repository

Kepler Monitoring of an L Dwarf I. The Photometric Period and White Light Flares

Citable link to this page

 

 
Title: Kepler Monitoring of an L Dwarf I. The Photometric Period and White Light Flares
Author: Gizis, John E.; Burgasser, Adam J.; Berger, Edo; Williams, Peter Kelsey George; Vrba, Frederick J.; Cruz, Kelle L.; Metchev, Stanimir

Note: Order does not necessarily reflect citation order of authors.

Citation: Gizis, John E., Adam J. Burgasser, Edo Berger, Peter K. G. Williams, Frederick J. Vrba, Kelle L. Cruz, and Stanimir Metchev. 2013. Kepler Monitoring of an L Dwarf I. The Photometric Period and White Light Flares. The Astrophysical Journal 779, no. 2: 172. doi:10.1088/0004-637x/779/2/172.
Full Text & Related Files:
Abstract: We report on the results of fifteen months of monitoring the nearby field L1 dwarf WISEP J190648.47+401106.8 (W1906+40) with the Kepler mission. Supporting observations with the Karl G. Jansky Very Large Array and Gemini North telescope reveal that the L dwarf is magnetically active, with quiescent radio and variable Hα emission. A preliminary trigonometric parallax shows that W1906+40 is at a distance of 16.35+0.36 −0.34 pc, and all observations are consistent with W1906+40 being an old disk star just above the hydrogen-burning limit. The star shows photometric variability with a period of 8.9 hours and an amplitude of 1.5%, with a consistent phase throughout the year. We infer a radius of 0.92 ± 0.07RJ and sin i > 0.57 from the observed period, luminosity (10−3.67±0.03L⊙), effective temperature (2300 ± 75K) , and v sin i (11.2 ± 2.2 km s−1 ). The light curve may be modeled with a single large, high latitude dark spot. Unlike many L-type brown dwarfs, there is no evidence of other variations at the & 2% level, either non-periodic or transient periodic, that mask the underlying rotation period. We suggest that the long-lived surface features may be due to starspots, but the possibility of cloud variations cannot be ruled out without further multi-wavelength observations. During the Gemini spectroscopy, we observed the most powerful flare ever seen on an L dwarf, with an estimated energy of ∼ 1.6 × 1032 ergs in white light emission. Using the Kepler data, we identify similar flares and estimate that white light flares with optical/ultraviolet energies of 1031 ergs or more occur on W1906+40 as often as 1-2 times per month.
Published Version: doi:10.1088/0004-637x/779/2/172
Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP
Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:30496615
Downloads of this work:

Show full Dublin Core record

This item appears in the following Collection(s)

 
 

Search DASH


Advanced Search
 
 

Submitters