ORCID Profile
0000-0002-3699-3134
Current Organisation
University of Colorado at Boulder
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Publisher: American Astronomical Society
Date: 04-2021
Abstract: We present the discovery of an extreme flaring event from Proxima Cen by the Australian Square Kilometre Array Pathfinder (ASKAP), Atacama Large Millimeter/submillimeter Array (ALMA), Hubble Space Telescope (HST), Transiting Exoplanet Survey Satellite (TESS), and the du Pont Telescope that occurred on 2019 May 1. In the millimeter and FUV, this flare is the brightest ever detected, brightening by a factor of and ,000 as seen by ALMA and HST, respectively. The millimeter and FUV continuum emission trace each other closely during the flare, suggesting that millimeter emission could serve as a proxy for FUV emission from stellar flares and become a powerful new tool to constrain the high-energy radiation environment of exoplanets. Surprisingly, optical emission associated with the event peaks at a much lower level with a time delay. The initial burst has an extremely short duration, lasting for s. Taken together with the growing s le of millimeter M dwarf flares, this event suggests that millimeter emission is actually common during stellar flares and often originates from short burst-like events.
Publisher: American Astronomical Society
Date: 03-06-2014
Publisher: American Astronomical Society
Date: 25-05-2016
Publisher: American Astronomical Society
Date: 10-2022
Abstract: We present millimeter, optical, and soft X-ray observations of a stellar flare with an energy squarely in the regime of typical X1 solar flares. The flare was observed from Proxima Cen on 2019 May 6 as part of a larger multi-wavelength flare monitoring c aign and was captured by Chandra, the Las Cumbres Observatory Global Telescope, the Iréné du Pont Telescope at Las C anas Observatory, and the Atacama Large Millimeter Array. Millimeter emission appears to be a common occurrence in small stellar flares that had gone undetected until recently, making it difficult to interpret these events within the current multi-wavelength picture of the flaring process. The May 6 event is the smallest stellar millimeter flare detected to date. We compare the relationship between the soft X-ray and millimeter emission to that observed in solar flares. The X-ray and optical flare energies of 10 30.3 ± 0.2 and 10 28.9 ± 0.1 erg, respectively, the coronal temperature of T = 11.0 ± 2.1 MK, and the emission measure of 9.5 ± 2.2 × 10 49 cm −3 are consistent with M-X class solar flares. We find the soft X-ray and millimeter emission during quiescence are consistent with the Güdel–Benz relation, but not during the flare. The millimeter luminosity is × higher than that of an equivalent X1 solar flare and lasts only seconds instead of minutes as seen for solar flares.
Location: United States of America
No related grants have been discovered for Steven Cranmer.