Andrew Yee
July 30th 05, 03:50 PM
Media Relations
University of California Berkeley
Media Contacts:
Robert Sanders, (510) 643-6998
Additional Resources:
Alex Filippenko, UC Berkeley
(510) 642-1813
Weidong Li, UC Berkeley
(510) 643-8973
FOR IMMEDIATE RELEASE: Thursday, July 28, 2005
Hubble pinpoints red supergiant that exploded
A series of lucky breaks has allowed two University of California,
Berkeley, astronomers to track down the identity of a distant star that
exploded a month ago in the majestic Whirlpool Galaxy.
While astronomers can predict which stars will end their lives in a fiery
explosion, surprisingly only five supernovas before now had been traced
back to a known star, according to one of the astronomers, UC Berkeley
astronomy professor Alex Filippenko. Most supernovas are too distant, or
their progenitor stars too faint or in too crowded fields for astronomers
to look back in historical sky photos in order to pinpoint the location
and type of star.
The Space Telescope Science Institute (STScI) today (Thursday, July 28)
released photos of the beautiful Whirlpool Galaxy, M51, showing the
location of the original star and the bright supernova just 12 days after
its explosion was discovered.
The supernova, dubbed SN 2005cs, belongs to a class of exploding stars
called "Type II-plateau." A supernova of this type results from the
collapse and subsequent explosion of a massive star whose light remains at
a constant brightness (a "plateau") for a period of time.
This finding is consistent with the idea that the progenitors of supernova
explosions are red, supergiant stars with masses eight to 15 times the
sun's mass. The progenitor star of SN 2005cs was found to be at the low
end of the mass range for supernova explosions. Stars with masses lower
than eight solar masses do not explode as supernovae at all, but rather
blow off their outer atmospheres to become planetary nebulae before
contracting to white dwarfs.
A German amateur astronomer was the first to note the unusually bright
star -- perhaps a supernova -- in M51, and he asked the staff at the
Central Bureau for Astronomical Telegrams to post a note to that effect on
June 29. Filippenko, who specializes in supernovae and black holes,
received the notice late that afternoon and rushed to get one of his
former students to request a spectrum of the brightly burning star from a
telescope in Arizona. This spectrum confirmed that it was a Type II
supernova.
Filippenko, by chance, was at the very end of a year-long observational
program using the Hubble Space Telescope, and he worked during an
overnight flight and early the next morning to submit a request to observe
the supernova before his opportunity ended at 5 p.m. Eastern time June 30.
Since Hubble can easily resolve stars in nearby galaxies, such as the
Whirlpool, it was the only chance he had to track down the exploding
star's identity. The new picture was needed for comparison with archival
images in order to accurately determine the position of the supernova.
He got in under the wire, convincing the telescope crew to observe the
waning supernova on July 11, amidst the hoopla and frequent observations
of the Deep Impact probe's collision with comet Temple I.
"This will be one of Hubble's many legacies," Filippenko said. "No other
telescope program could observe the exact location of this Type II
supernova, yet it was an opportunity not to be missed."
From the brand new Hubble image and a January 2005 image Hubble had taken
of the Whirlpool Galaxy, UC Berkeley research astronomer Weidong Li and
Filippenko were able to pinpoint the location of the progenitor star and
identify it as a red supergiant whose mass is about seven to 10 times that
of the sun.
"This is a great example of the excitement of science, when something
happens and you have to jump on it right away," said Filippenko, who is
known for the enthusiasm he brings to teaching. "Some nights you just
don't sleep."
Filippenko, Li and colleague Schuyler Van Dyk of Caltech's Spitzer Science
Center first reported their findings in IAU circulars 8556 and 8565 on
July 3 and July 12, respectively. The team submitted a full paper
describing their research to The Astrophysical Journal on July 18.
The Space Telescope Science Institute is operated for NASA by the
Association of Universities for Research in Astronomy, Inc., under
contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble
Space Telescope is a project of international cooperation between NASA and
the European Space Agency.
Web Links to additional Information:
http://www.hubblesite.org/news/2005/21
University of California Berkeley
Media Contacts:
Robert Sanders, (510) 643-6998
Additional Resources:
Alex Filippenko, UC Berkeley
(510) 642-1813
Weidong Li, UC Berkeley
(510) 643-8973
FOR IMMEDIATE RELEASE: Thursday, July 28, 2005
Hubble pinpoints red supergiant that exploded
A series of lucky breaks has allowed two University of California,
Berkeley, astronomers to track down the identity of a distant star that
exploded a month ago in the majestic Whirlpool Galaxy.
While astronomers can predict which stars will end their lives in a fiery
explosion, surprisingly only five supernovas before now had been traced
back to a known star, according to one of the astronomers, UC Berkeley
astronomy professor Alex Filippenko. Most supernovas are too distant, or
their progenitor stars too faint or in too crowded fields for astronomers
to look back in historical sky photos in order to pinpoint the location
and type of star.
The Space Telescope Science Institute (STScI) today (Thursday, July 28)
released photos of the beautiful Whirlpool Galaxy, M51, showing the
location of the original star and the bright supernova just 12 days after
its explosion was discovered.
The supernova, dubbed SN 2005cs, belongs to a class of exploding stars
called "Type II-plateau." A supernova of this type results from the
collapse and subsequent explosion of a massive star whose light remains at
a constant brightness (a "plateau") for a period of time.
This finding is consistent with the idea that the progenitors of supernova
explosions are red, supergiant stars with masses eight to 15 times the
sun's mass. The progenitor star of SN 2005cs was found to be at the low
end of the mass range for supernova explosions. Stars with masses lower
than eight solar masses do not explode as supernovae at all, but rather
blow off their outer atmospheres to become planetary nebulae before
contracting to white dwarfs.
A German amateur astronomer was the first to note the unusually bright
star -- perhaps a supernova -- in M51, and he asked the staff at the
Central Bureau for Astronomical Telegrams to post a note to that effect on
June 29. Filippenko, who specializes in supernovae and black holes,
received the notice late that afternoon and rushed to get one of his
former students to request a spectrum of the brightly burning star from a
telescope in Arizona. This spectrum confirmed that it was a Type II
supernova.
Filippenko, by chance, was at the very end of a year-long observational
program using the Hubble Space Telescope, and he worked during an
overnight flight and early the next morning to submit a request to observe
the supernova before his opportunity ended at 5 p.m. Eastern time June 30.
Since Hubble can easily resolve stars in nearby galaxies, such as the
Whirlpool, it was the only chance he had to track down the exploding
star's identity. The new picture was needed for comparison with archival
images in order to accurately determine the position of the supernova.
He got in under the wire, convincing the telescope crew to observe the
waning supernova on July 11, amidst the hoopla and frequent observations
of the Deep Impact probe's collision with comet Temple I.
"This will be one of Hubble's many legacies," Filippenko said. "No other
telescope program could observe the exact location of this Type II
supernova, yet it was an opportunity not to be missed."
From the brand new Hubble image and a January 2005 image Hubble had taken
of the Whirlpool Galaxy, UC Berkeley research astronomer Weidong Li and
Filippenko were able to pinpoint the location of the progenitor star and
identify it as a red supergiant whose mass is about seven to 10 times that
of the sun.
"This is a great example of the excitement of science, when something
happens and you have to jump on it right away," said Filippenko, who is
known for the enthusiasm he brings to teaching. "Some nights you just
don't sleep."
Filippenko, Li and colleague Schuyler Van Dyk of Caltech's Spitzer Science
Center first reported their findings in IAU circulars 8556 and 8565 on
July 3 and July 12, respectively. The team submitted a full paper
describing their research to The Astrophysical Journal on July 18.
The Space Telescope Science Institute is operated for NASA by the
Association of Universities for Research in Astronomy, Inc., under
contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble
Space Telescope is a project of international cooperation between NASA and
the European Space Agency.
Web Links to additional Information:
http://www.hubblesite.org/news/2005/21