Monday, March 22, 2010

Unusual stellar eruption, comet fragmentation make news

The star V407 Cygni was previously classified as a symbiotic star, a binary star system in which a red giant transfers mass to a white dwarf companion. Occasionally, the material on the white dwarf becomes hot enough that it begins to undergo nuclear fusion, and the system goes into outburst. A similar process occurs in classical novae, but in the symbiotic stars these outbursts are less intense and a more steady process while in classical novae the thermonuclear ignition is explosive - and on March 10 V 407 Cyg actually underwent what appears to be just such a classical nova explosion! Furthermore the star is now also suspected of being a gamma ray transient, something never observed in a symbiotic system. Observations are encouraged; articles and updates are here (alt.), here, here (earlier), here, hier and here. • Also news about the variables GW Lib and GK Per.

The nucleus of comet C/2007 Q3 (Siding Spring) has split, though the fragment in the coma requires larger instruments to see: Stories of March 22, March 19, March 17 and March 9, several pictures and selected ones of March 14, March 19, March 20, March 21 and March 22 (zoom, more zoom). • Also 29P in outburst on March 18, 81P/Wild with nice tail & coma details on March 6, March 8, March 12, March 19 and March 21 - and the dusty streak of C/2010 A2 was still there on March 4, March 7 and March 11. • The discoveries of P/2001 Q11 after 9 years, C/2010 E5 (Scotti), C/2010 E1 & E2 (the latter involving D. Levy). • 30P met 31P on March 4, Rosetta target comet 67P is still visible for experts (but then gone til he encounter), and several Kreutz comets fell into the Sun in mid-March (mehr, mehr). • Also a bolide in Hungary and speculation about an impact crater in the D.R.Congo.

In other news there was a big sunspot group in mid-March, the understanding of the solar cycle may advance (more, more), while the Sun may now return to normal activity levels after a Grand Maximum lasting the past 60-70 years. • Mars pics of March 19 (more, more), March 11 (1 to 11), March 8, March 7 (more), March 6, March 4 (more) and March 1 (more). • Jupiter's GRS in thermal IR (more, more, more and mehr), several Titan transits in 2009/10 and Saturn in opposition (earlier). • Venus & the lunar crescent on March 17 and March 16 and the Moon on the 16th from the ISS; also a movie of the ISS in hi-res and an ISS Sun transit. • A Messier Marathon report from India and another one, a new public observatory and an article (PDF) on remote observing and how it helps amateurs hunt exoplanets.

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