TY - JOUR
T1 - The Mouse That Squeaked: A Small Flare from Proxima Cen Observed in the Millimeter, Optical, and Soft X-Ray with Chandra and ALMA
T2 - A small flare from Proxima Cen observed in the millimeter, optical, and soft X-ray with Chandra and ALMA
AU - Howard, Ward S.
AU - MacGregor, Meredith A.
AU - Osten, Rachel
AU - Forbrich, Jan
AU - Cranmer, Steven R.
AU - Tristan, Isaiah
AU - Weinberger, Alycia J.
AU - Youngblood, Allison
AU - Barclay, Thomas
AU - Parke Loyd, R. O.
AU - Shkolnik, Evgenya L.
AU - Zic, Andrew
AU - Wilner, David J.
N1 - © 2022. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/
PY - 2022/10/18
Y1 - 2022/10/18
N2 - 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 campaign and was captured by Chandra, the Las Cumbres Observatory Global Telescope, the Iréné du Pont Telescope at Las Campanas 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 1030.3 ± 0.2 and 1028.9 ± 0.1 erg, respectively, the coronal temperature of T = 11.0 ± 2.1 MK, and the emission measure of 9.5 ± 2.2 × 1049 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 >100× higher than that of an equivalent X1 solar flare and lasts only seconds instead of minutes as seen for solar flares.
AB - 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 campaign and was captured by Chandra, the Las Cumbres Observatory Global Telescope, the Iréné du Pont Telescope at Las Campanas 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 1030.3 ± 0.2 and 1028.9 ± 0.1 erg, respectively, the coronal temperature of T = 11.0 ± 2.1 MK, and the emission measure of 9.5 ± 2.2 × 1049 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 >100× higher than that of an equivalent X1 solar flare and lasts only seconds instead of minutes as seen for solar flares.
KW - 340
KW - Stars and Stellar Physics
U2 - 10.3847/1538-4357/ac9134
DO - 10.3847/1538-4357/ac9134
M3 - Article
SN - 0004-637X
VL - 938
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 2
M1 - 103
ER -