Friday, April 17, 2009

Supernova with 13 to 14 mag. in a galaxy in Ursa Major!

It's rare to have a supernova brighter than 15th or 16th magnitude, so SN 2009dd in NGC 4088 in UMa which has about 13.5 mag. is something special. Here are one of the discovery images (the SN was found independently by two Italian teams), a picture taken soon thereafter by a German amateur (before the SN even had a number) and a nice picture of the galaxy itself. SN 2009dd has the typical spectrum of a young type II supernova, a few days after its explosion - which took place some time between April 2 and 4 as Japanese images (found later) show. • In other variable star news, an outburst of IY UMa is underway and a variable in a planetary nebula and a transit of exoplanet XO-1b have been observed.

• In the current deep solar minimum even coronal mass ejections are slower than typical (while their 3D structure is clearer now thanks to STEREO). Also a prominence video, an asteroid named after the last total solar eclipse or rather a prime viewing spot in China, and why there will be no tsunami following the next TSE. • An unusually deep wide-field sky image with 40 hours of exposure time is causing attention.

• A fine Jupiter from down-under, a nice Saturn with Rhea's shadow on the disk and a table of Titan transits - of which not a single one will be visible in Europe. • Did Venus' atmosphere show a closed ring during inferior conjunction or at least arcs all around as this picture may indicate? The Japanese archive has nothing similar, though nearly closed rings were detected 2 days before the last transit of Venus (the exact time and a somewhat later image). Meanwhile here is Venus on April 11.

• More bolides, in Austria on April 9 and in California on April 7. • The Field Museum has received a lot of meteorites while the largest one in Texas has been found and the videographer honored who taped the bolide, a call for searchers in Canada is out w.r.t. last year's meteorite rain - and sometimes dogs make good hunters for meteorites! • There is another comet discovery with the STEREO spacecraft by an amateur, though the comet is less interesting per se than Yi-SWAN (more stories here and here and pics of April 12 and April 9 and more). • Also Cardinal at M 38 (more), the recovery of an old LINEAR and 19P on April 12.

• The Lyrid meteors will peak on the morning of April 22 when - for some places - even more will happen when the Moon occults Venus. • Predictions of star occultations by the Moon can be greatly improved thanks to Kaguya and its laser altimeter. • A plane in front of the rising Moon (from this report), the ISS in front of the Sun (more) and the Moon in daylight, good pics from March and recent ones - and another claim of an astronaut 'detection' during an EVA. • Finally a pro-am session during a big conference in the U.K. (PDF pages 321-4), the LookUP! tool, good Aussie astrophotographers - and some stories (more, more and here) on the Birkat Hachamah non-astronomical but rare event. Of which now only a T-shirt is left ...

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