Space Station Returns; Bright Supernova Flares In Virgo Galaxy

A sea of aurora seen from one of the windows of the space station earlier this year. Credit: NASA

The International Space Station (ISS) is back at dawn for the next few weeks. If you’re up early, take a look at the brightest satellite of them all. On good passes the ISS is nearly as bright as Venus in the western sky right now. From its vantage point 240 miles above the Earth, the astronauts must have had fabulous views of northern lights these past few weeks. Unfortunately I can’t find any good recent pictures, but the one above, taken on January 25, reminds me of looking down on the clouds from a mountaintop – only it’s aurora!

The bottom edge of a typical aurora is about 60 miles high (rarely 50 miles during intense storms); the top about 200 miles but occasionally reaching up to 350 miles. “We can actually fly into the auroras,” said NASA astronaut Don Pettit in a recent article on Space.com, a space station flight engineer for the current Expedition 30. “It’s like being shrunk down and put inside of a neon sign.”

Viewing times for the space station below are for the Duluth, Minn. region. To find exact times when the space station will pass over your town, log on to Heavens Above or type in your zip code on Spaceweather’s Satellite Flybys page. The ISS looks like a brilliant star moving from west to east and takes about 4 minutes to cross from one side of the sky to the other.

* Mon. March 19 starting at 5:19 a.m. Appears very low in the southeastern sky
* Tues. March 20 at 5:56 a.m. Much easier to see! Bright pass across the south
* Weds. March 21 at 6:34 a.m.  Brilliant pass nearly overhead
* Thurs. March 22 at 5:40 a.m. Another fine flyby high in the south
* Fri. March 23 at 6:17 a.m. Bright pass across the northern sky. Zips just above the North Star.
* Sat. March 24 at 5:21 a.m. Reappears from Earth’s shadow below the Big Dipper and moves straight across the top of the sky.

New supernova 2012 au shines in the center of the small 12.4 magnitude galaxy NGC 4790 in Virgo. North is up and east to the left in photo. Credit: Joseph Brimacombe

A new bright supernova was discovered on March 14 very near the center of the barred spiral galaxy NGC 4790 in Virgo. Called SN 2012 au, amateur astronomers with 8-inch telescopes or larger can get a good look at it in the southeastern sky starting around 11 p.m. It’s currently magnitude 12.7-13.0 and with the right instrument can’t be missed.  I easily spotted it two nights ago at low power in my 15-inch. A sharp-eyed observer might snag it in a 6-incher especially if it continues to brighten.

The “new star” radiates like a tiny beacon at almost the exact center of the galaxy, far outshining the millions of stars in its nucleus. In the photo above, the nucleus is the little dot just to the right of the supernova.

You can use this wide-view map to point you to the general vicinity of galaxy NGC 4790, located about 1/2 degree south of the 5th magnitude star Psi Virginis. Maps created with Stellarium

2012 au is classified as a Type Ib supernova. Before it imploded and then exploded, it was a massive supergiant star that blew off its outer hydrogen atmosphere, exposing an interior rich in more complex elements like helium, carbon and oxygen. Fortunately for skywatchers, most huge stars end their life in spectacular fashion after exhausting the fuel in their cores.

Closeup view of NGC 4790 with SN 2012 au. The yellow circle measures about 1 degree across. Find Psi in your scope and you're nearly there! Two other galaxies near 4790 are also shown. North is up and east to the left.

With no heat pressure from nuclear burning to fend off gravity’s hand, the star collapses in a matter of seconds. As matter falls toward the supergiant’s core, it creates a powerful shock wave that rebounds and rips the star apart in one fantastic explosion we see as a supernova. For more information on SN 2012 au and other recent supernovae, stop by Dave Bishop’s Latest Supernovae site.

9 Responses

  1. jane

    So i heard that planet naribu was spotted in antartica and is being hidden by chem trails….bogus right??? Feed me some info please

    1. astrobob

      Jane,
      Niburu, etc. is made-up pseudoscience with not a shred of scientific evidence behind it. No need to waste your time.

  2. Richard Wiggins

    Im a security guard in Ormond Beach Florida at a vacant facility way out of any city lights and since March 18th 2012 just south of the triangulation of stars that make up the front shoulder of LEO, between 11:00PM and @:00AM I’m seeing a fairly bright flash at about 3 to 5 min. intrevals. Do you know what I’m seeing ? Please e-mail me and let me know if anyone else is reporting it. On the night of the 20th Sun I hqad my girlfriend come out to see it. She was amazed. I’ve also veiwed through my night vision goggles Wow what a sight !!!

    1. astrobob

      Richard,
      From your description, the place in the sky you describe is where the planet Mars is right now. Seeing it in the same spot each night makes it sound even more so like Mars. Only thing is, Mars doesn’t flash the way you described. The only other thing I can think of is a geosynchronous satellite, but those would further down well beneath the tail of Leo. Sometimes one of those can flash bright enough to see with the naked eye.

  3. dr turbo

    dear astrobob, this past friday, yesterday, while walking my dog i noticed what looked like a planet in ursa major, more specifically just off the last star of the handle of the big dipper. it looked unusual and as i was walking and looking at it the light went out. very strange, supernova or something else? this was approximately 4:40 friday a.m. the light was steady yellow to white not star like

    1. astrobob

      Dr. Turbo,
      Bright star that faded – it sounds a lot like an Iridium satellite. They can pretty suddenly appear, move very slowly and then quickly fade. It wouldn’t be a supernova. Those last much longer and are visible in a telescope.

  4. Raya Dastidar

    hi,
    Is there any published paper or something to find out the metallicity of the galaxy 4790 at the site of SN explosion?

    1. astrobob

      Raya,
      Metallicity refers to stars rather than galaxies. Some stars have more “metals”, others less, depending on when (and to some degree where) they formed. Unfortunately, I don’t know where you’d find information on the original star’s metallicity. It was a very faint object no one paid any particular attention to until it blew up.

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