UConn Physics Colloquium
Connecting Magnetic Reconnection Events with Superflares on Sun-like Stars and Giant Extra-solar Planets
Professor Eric P.
Smith College Astronomy Department
Clark Science Center
Magnetic reconnection events (MRE) occur in laboratory plasmas, the solar atmosphere and in many other astrophysical environments. Despite the ferocious energy release common in terrestrial and solar magnetic reconnection events, and their damaging effects to terrestrial equipment, we still do not have an extremely clear picture of the exact mechanism by which reconnection occurs. Although detailed questions remain, the astrophysical evidence of MRE is clear. Reconnection events lead to highly energetic outbursts that have broadband emission and characteristic timescales. Stars of the RS CVn class of close binaries are well known for their MRE which have a total luminosity of 1033 to 1038 ergs lasting from 103 to 105 s.
Recently we have realized that there is a class of Sun-like stars which have nearly identical outbursts, yet are not in a close binary system. These outbursts are surprising because Sun-like stars lacking a close stellar partner have only been observed to have flare events with less than ~1031 ergs. Binary companions are necessary to explain large scale MRE, i.e. more than ~1031 ergs, since the energy budget scales as the volume of the region experiencing the reconnection event. A small area yields a small explosion. A scenario will be presented in which the magnetosphere of a Jupiter-like planet interacts with the magnetosphere of its host star and subsequently experiences the observed powerful MRE. The planet mediated interaction provides for the required large volume without leading to the radial velocity variations arising from a stellar binary. The requirement of a powerful magnetosphere in close proximity to the star also naturally explains the apparent lack of such outbursts on the Sun.
Friday, January 25, 2002
Gant Science Complex
(Refreshments will be served beginning at 3:30 in the Physics Library, Room P-103)