Flares, Rotation, and Planets of the AU Mic System from TESS Observations
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Gilbert_2022_AJ_163_147.pdf
Description
Published version
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2.19 MB
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Checksum (MD5)
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Author(s)
Gilbert, Emily A
Barclay, Thomas
Quintana, Elisa V
Walkowicz, Lucianne M
Vega, Laura D
Schlieder, Joshua E
Monsue, Teresa
Cale, Bryson L
Collins, Kevin I
Gaidos, Eric
Date Issued
2022
Journal
Astronomical Journal
Publisher
American Astronomical Society
Citation
Gilbert, Emily A, Barclay, Thomas, Quintana, Elisa V, Walkowicz, Lucianne M, Vega, Laura D et al. 2022. "Flares, Rotation, and Planets of the AU Mic System from TESS Observations." Astronomical Journal, 163 (4).
Version
Final published version
Abstract
Abstract
AU Mic is a young (∼24 Myr), pre-main-sequence M dwarf star that was observed in the first month of science observations of the Transiting Exoplanet Survey Satellite (TESS) and reobserved 2 years later. This target has photometric variability from a variety of sources that is readily apparent in the TESS light curves; spots induce modulation in the light curve, flares are present throughout (manifesting as sharp rises with slow exponential decay phases), and transits of AU Mic b may be seen by eye as dips in the light curve. We present a combined analysis of both TESS Sector 1 and Sector 27 AU Mic light curves including the new 20 s cadence data from TESS Year 3. We compare flare rates between both observations and analyze the spot evolution, showing that the activity levels increase slightly from Sector 1 to Sector 27. Furthermore, the 20 s data collection allows us to detect more flares, smaller flares, and better resolve flare morphology in white light as compared to the 2 minute data collection mode. We also refine the parameters for AU Mic b by fitting three additional transits of AU Mic b from Sector 27 using a model that includes stellar activity. We show that the transits exhibit clear transit timing variations with an amplitude of ∼80 s. We also detect three transits of a 2.8 R ⊕ planet, AU Mic c, which has a period of 18.86 days.
AU Mic is a young (∼24 Myr), pre-main-sequence M dwarf star that was observed in the first month of science observations of the Transiting Exoplanet Survey Satellite (TESS) and reobserved 2 years later. This target has photometric variability from a variety of sources that is readily apparent in the TESS light curves; spots induce modulation in the light curve, flares are present throughout (manifesting as sharp rises with slow exponential decay phases), and transits of AU Mic b may be seen by eye as dips in the light curve. We present a combined analysis of both TESS Sector 1 and Sector 27 AU Mic light curves including the new 20 s cadence data from TESS Year 3. We compare flare rates between both observations and analyze the spot evolution, showing that the activity levels increase slightly from Sector 1 to Sector 27. Furthermore, the 20 s data collection allows us to detect more flares, smaller flares, and better resolve flare morphology in white light as compared to the 2 minute data collection mode. We also refine the parameters for AU Mic b by fitting three additional transits of AU Mic b from Sector 27 using a model that includes stellar activity. We show that the transits exhibit clear transit timing variations with an amplitude of ∼80 s. We also detect three transits of a 2.8 R ⊕ planet, AU Mic c, which has a period of 18.86 days.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.3847/1538-3881/AC23CA
