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Re: Yahoo! News Story - Astronomers spot Milky Way's youngest supernova - Ya

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  • mahtezcatpoc
    http://chandra.harvard.edu/photo/2008/g19/ Coordinates (J2000) RA 17h 48m 45s | Dec -27° 10 00 28 Sagittarius 19. I m calling this one Reynolds Star.
    Message 1 of 2 , May 28 8:45 PM
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      http://chandra.harvard.edu/photo/2008/g19/

      "Coordinates (J2000)
      "RA 17h 48m 45s | Dec -27° 10' 00" "

      28 Sagittarius 19.

      I'm calling this one Reynolds' Star.


      Mark A. Holmes


      > --- In thefixedstars@yahoogroups.com, Mark Andrew Holmes
      > <mahtezcatpoc@> wrote:
      > >
      > >
      > > Mark Andrew Holmes (mahtezcatpoc@) has sent you a news article.
      > > (Email address has not been verified.)
      > > ------------------------------------------------------------
      > > Personal message:
      > >
      > >
      > >
      > > Astronomers spot Milky Way's youngest supernova - Yahoo! News
      > >
      > > http://news.yahoo.com/s/afp/20080515/ts_alt_afp/usastronomysupernova
      > >
      >
      >
      > BLGD...
      >
      >
      > Mark A. Holmes
      >
      >
      >
      > --Begin story.
      >
      >
      > Astronomers spot Milky Way's youngest supernova
      >
      > by Jean-Louis Santini Thu May 15, 8:44 AM ET
      >
      > WASHINGTON (AFP) - Astronomers have discovered the most recent
      > supernova in our Milky Way, hoping it will further knowledge about the
      > spectacular stellar explosions and the workings of our galaxy, a
      > research paper said Wednesday.
      >
      > Named G1.9+0.3, the supernova in the constellation Sagittarius is some
      > 140 years old and was detected through radio and X-ray telescopes,
      > since the original, dazzling explosion was hidden from view by a dense
      > field of gas and dust near the galaxy center, where it took place.
      >
      > It is about 200 years younger than Cassiopeia A, the last known Milky
      > Way supernova that exploded around 1680. Age estimates are based on
      > the rate of expansion of the supernova remains -- the faster the
      > expansion the more recent the explosion.
      >
      > Stephen Reynolds of North Carolina State University in Raleigh, who
      > led the study, said the new supernova was first noticed by astronomers
      > more than 20 years ago, when the original explosion was estimated to
      > have happened 400-1,000 years ago.
      >
      > Its more recent origin became apparent, he said, when images of the
      > object taken in 2007 through NASA's Chandra X-ray Observatory were
      > compared with the 1985 images of the National Radio Astronomy
      > Observatory's Very Large Array, which also belongs to NASA.
      >
      > In the intervening 22 years, Reynolds said, the supernova remnants had
      > expanded about 16 percent, indicating that they were much younger than
      > previously thought.
      >
      > Measurements taken earlier this year by the Very Large Array confirmed
      > the age of the supernova remains at 140 years, possibly less if the
      > expansion has been slowing down, making it the youngest on record in
      > the Milky Way, the astrophysicist said.
      >
      > With an unobstructed view, had the supernova not taken place near the
      > center of the galaxy, the stellar explosion would have been visible in
      > 1870-1900 in Sagittarius and probably taken for a new star, he
      explained.
      >
      > "We can see some supernova explosions with optical telescopes across
      > half of the universe, but when they're in this murk we can miss them
      > in our own cosmic backyard," Reynolds said in a telephone press
      > conference.
      >
      > "Fortunately, the expanding gas cloud from the explosion shines
      > brightly in radio waves and X-rays for thousands of years. X-ray and
      > radio telescopes can see through all that obscuration and show us what
      > we've been missing."
      >
      > He said astronomers normally observe ancient supernova remnants with
      > small rates in expansion that are very difficult to measure.
      >
      > The remains of the galaxy's most recent supernova are very brilliant
      > and should afford astronomers keener insight into the phenomenon and
      > its effects on the surrounding galaxy, Reynolds said.
      >
      > "No other object in the galaxy has properties like this," he said.
      > "This find is extremely important for learning more about how some
      > stars explode and what happens in the aftermath."
      >
      > Supernovae occur when stars run out of nuclear fuel and explode,
      > providing crucial information about the universe's history.
      >
      > They heat and redistribute large amounts of gas, and pump heavy
      > elements out into their surroundings and can trigger the formation of
      > new stars as part of a cycle of stellar death and rebirth.
      >
      > The explosion also can leave behind, in addition to the expanding
      > remnant, a central neutron star or black hole.
      >
      > A rare occurrence in the span of a human lifetime, supernovae are
      > estimated to happen about three times per century in the Milky Way.
      >
      > "If the supernova rate estimates are correct, there should be the
      > remnants of about 10 supernova explosions that are younger than
      > Cassiopeia A," said David Green of the University of Cambridge in the
      > United Kingdom, who led the Very Large Array study.
      >
      > "It's great to finally track one of them down."
      >
      > The study is published in the January 10 issue of The Astrophysical
      > Journal Letters.
      >
      >
      > --End story.
      >
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