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01/30/2014 – Ephemeris – More on the supernova in M82
Ephemeris for Thursday, January 30th. The sun will rise at 8:03. It’ll be up for 9 hours and 45 minutes, setting at 5:48. The moon is new today, and won’t be visible.
Let’s talk more about our new supernova in galaxy M82 off the bowl of the Big Dipper. Of course new and nova used in the same sentence is a bit redundant because Nova is Latin for Stella Nova or new star. It is thought that tiny massive white dwarf stars near the end of their life are involved in some way. Type 1a supernovae all seem to explode with about the same brightness so it’s thought that they accrete matter from a nearby giant star until their mass gets to about 1.44 times the sun’s mass. That that point they explode. The explosion of 1.44 solar masses is what gives them the common brightness. The 1.44 of the sun’s mass is called the Chandrasekhar limit discovered mathematically in 1930 by the Indian-American astronomer of the same name.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Finder Chart for M82 and M81. Actual time is 9 p.m. on January 28, 2014. Created using Cartes du Ciel (Sky Charts).
Discovery image of SN 2014J. Credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright.
Check here for the Wikipedia article on astrophysicist Subrahmanyan Chandrasekhar and the Chandrasekhar limit.
Chandra, as he was know was honored four years after his death with the naming of the Chandra X-ray Observatory, one of NASA’s Great Observatories launched in 1999 and still operating.
01/28/2014 – Ephemeris – A supernova found in a nearby galaxy
Ephemeris for Tuesday, January 28th. The sun will rise at 8:05. It’ll be up for 9 hours and 40 minutes, setting at 5:45. The moon, 2 days before new, will rise at 6:40 tomorrow morning.
There is a new supernova in our skies. It’s designation is SN 2014J and it’s pretty close as the things go, but not in our galaxy. It’s in another galaxy M82 off the front of the bowl of the Big Dipper, and 12 million light years away. It’s the closest supernova since supernova 1987A, which appeared on the last days of February 1987 in a companion galaxy to us the Large Magellanic Cloud. While the latter was visible to the naked eye, this will stay a binocular object at best. I’ll have a finder chart and more information in bobmoler.wordpress.org for those that may need it. This is a special type of supernova that’s used for distance measurement in the universe called a type 1a and this will be a good time to fine tune the calibration.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Links to more discussion of the new supernova and type 1a supernovae in general.
Finder Charts
Finder Chart for M82 and M81. Actual time is 9 p.m. on January 28, 2014. Created using Cartes du Ciel (Sky Charts)
Pointer to M81 and M82 is a line diagonally through the bowl of the Big Dipper from the star Phad γ (gamma) Ursa Majoris through Dubhe α (alpha) Ursa Majoris. Note that the Big Dipper is not an official constellation but part of Ursa Major, the Great Bear.
M82 and M81 as seen close up. Note the spiral arms of M81 are invisible visually. Created using Cartes du Ciel (Sky Charts).
Discovery image of SN 2014J. Credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright.
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