The Chandra Deep Field-North Survey: XVII. Evolution of magnetic activity in old late-type stars

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dc.creatorFeigelson, E. D.
dc.creatorHornschemeier, A. E.
dc.creatorMicela, G.
dc.creatorBauer, F. E.
dc.creatorAlexander, D. M.
dc.creatorBrandt, W. N.
dc.creatorFavata, F.
dc.creatorSciortino, S.
dc.creatorGarmire, G. P.
dc.creatorState, Penn
dc.creatorHopkins, Johns
dc.creatorPalermo
dc.creatorCambridge
dc.creatorESTEC
dc.date2004-05-03
dc.date.accessioned2026-07-07T11:42:21Z
dc.date.available2026-07-07T11:42:21Z
dc.descriptionThe extremely sensitive Chandra Deep Field-North (CDF-N) pencil-beam X-ray survey is used to identify and characterize the X-ray emission from old high-latitude main sequence Galactic stars. Our principal goal is to investigate the expected long-term decay of magnetic activity of late-type stars due to the gradual spindown of stellar rotation from a magnetized stellar wind. Eleven X-ray sources constitute a well-defined sample of 2 G, 2 K0-K4, and 7 M2-M5 stars with median distance around 300 pc. X-ray luminosities are typically log Lx ~ 27 erg/s and is dominated by flares rather than quiescent coronal emission. Models of the population indicates that the CDF-N stars are the most magnetically active old disk stars. A substantial decline in X-ray luminosities over the 1<t<11 Gyr age interval is required. This is the first demonstration that the coronal and flaring components of stellar magnetic activity -- and presumably the interior magnetic dynamos responsible for the reconnecting fields at the stellar surface -- exhibit long-term decay over the age of the Galactic disk. The model that best fits the magnitudes, spectral types and X-ray luminosities of the sample has Lx ~ 1/t^2 erg/s which is faster than the 1/t decay rate predicted from widely accepted rotational spindown rates and X-ray-activity relations.
dc.description22 pages, 5 figures, accepted for publication in the Astrophysical Journal
dc.identifierhttps://arxiv.org/abs/astro-ph/0405026
dc.identifierhttp://arxiv.org/abs/astro-ph/0405026
dc.identifierAstrophys.J.611:1107-1120,2004
dc.identifierdoi:10.1086/422248
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/200855
dc.subjectAstrophysics
dc.titleThe Chandra Deep Field-North Survey: XVII. Evolution of magnetic activity in old late-type stars
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