[Solar System -- Oral ]
Chandra Studies of Planets and Comets in the X-ray
Carey Lisse, Johns Hopkins University Applied Physics Laboratory
A. Bhardwaj (Vikram Sarabhai Space Centre), S. J. Wolk (CXC), D. J. Christian (CSUN), K. Dennerl (MPE), D. Bodewits (GSFC), T.H. Zurbuchen (UMich)
The discovery of high energy x-ray emission in 1996 from
C/1996 B2 (Hyakutake) created a new class of solar system x-ray emitting
objects [1]. Subsequent detections of the morphology, spectra, and time
dependence of the x-rays from more than 20 comets have shown that the
very soft (E < 1 keV) emission is due to a charge-exchange interaction
between highly charged solar wind minor ions and the comet's extended
neutral atmosphere [2,3]. Several other solar system objects are now
known to shine in the X-ray, including Venus, Mars, the Moon, the Earth,
Jupiter, and Saturn, with total power outputs on the MW - GW scale [4].
Like comets, the X-ray emission from the Earth's geo-corona, the Jovian
aurora, and the Martian halo are all driven by charge exchange between
highly charged minor (heavy) ions in the solar wind and gaseous neutral
species in the bodies' atmosphere. The first soft X-ray observation of
Earth’s aurora by Chandra shows that it is highly variable, and the
Jovian aurora is a fascinating puzzle that is just beginning to yield
its secrets. The non-auroral X-ray emissions from Jupiter, Saturn, and
Earth, and those from disks of Mars, Venus, and the Moon are mainly
produced due to scattering of solar X-rays We present a summary of recent planetary and cometary observations by
the Chandra, CHIPS, EUVE, ROSAT, Swift, and XMM spacecraft, in conjunction
with solar wind measurements made by the ACE, IMP-8, SOHO, and TRACE
spacecraft, in order to demonstrate the richness and utility of solar
system x-ray emission.References[1] C.M. Lisse et al., Science 274, 205 (1996)[2] R. Wegmann and K. Dennerl, A&A 430, L33 (2005)[3] D. Bodewits et al., A&A 469, 1183 (2007)[4] A. Bhardwaj et al., PSS 55, 1135 - 1189 (2007)