Baby Supernova in Our Neighborhood

Baby Supernova in Our Neighborhood

WASHINGTON, May 14 - A baby supernova, just over
a century old, has been found in the middle of our own Milky
Way galaxy and provides an unprecedented opportunity to watch a
star dying, astronomers said on Wednesday.
The supernova, known as G1.9+0.3, would have made a bright
flash when it first exploded 140 years ago but was not seen
because dust obscures it, David Green of Britain’s University
of Cambridge and colleagues reported.
“It’s by far the youngest supernova identified in the
galaxy,” Green told reporters in a telephone briefing.
Green first identified the object in 1985 as a possible
supernova, using radio readings from the U.S. National Science
Foundation’s Very Large Array.
In 2007, Stephen Reynolds of North Carolina State
University and colleagues looked at it using the orbiting
Chandra X-Ray Observatory. They were surprised to find it was
16 percent bigger than the radio measurements.
“The only reasonable explanation we could come up with was,
in the 22 years between those observations, it had grown by
that rate,” Reynolds said.
They extrapolated its rate of growth to date the original
explosion at 140 years ago.
The supernova is at the center of the galaxy, roughly
25,000 light-years from Earth. A light-year is the distance
light travels in one year — about 5.8 trillion miles (9.5
trillion km).
Reynolds says the discovery renews the question of why so
few supernovae have been seen in the Milky Way. Based on other
galaxies, astronomers have estimated that about three such
stellar explosions should occur every century.
The most recent supernova in Earth’s neighborhood known
until now occurred around 1680, creating the remnant called
Cassiopeia A.
“If the supernova rate estimates are correct, there should
be the remnants of about 10 supernova explosions in the Milky
Way that are younger than Cassiopeia A,” said Green.
“It’s great to finally track one of them down.”
Dust could be hiding most of them, Green and Reynolds said,
but X-ray and radio observations might find them.
“Looking out of the Milky Way, 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 back yard,” Reynolds said.
Writing in the Astrophysical Journal Letters and Monthly
Notices of the Royal Astronomical Society, the researchers said
they can now watch and analyze the explosion as it unfolds.
While more distant supernovae can be seen with the naked
eye, they quickly fade and the radio waves they create will
take centuries to arrive.
Dr. Robert Kirshner of the Harvard Smithsonian Center for
Astrophysics, who did not work on the study, said studying a
young supernova could help scientists understand the very
beginnings of life.
“The supernova makes a chemical element through real
alchemy — transforming one element into another one,” Kirshner
said.
The iron in blood, for instance, was made by a star.
“We are all stardust and it seems reasonable for us to want
to know how these elements get formed when stars explode,”
Kirshner added.
“Our planet, our cells, our pieces are made of the vanished
ashes of these exploded supernovae ... You are actually getting
to see the rock that made the splash, not the wave that is
going out into the pond.”(REUTERS)

CAPE CANAVERAL, Florida (AP) — Astronomers have discovered the
youngest known supernova in the Milky Way galaxy, still just a baby
at 140 years old.
The scientists, who announced their findings Wednesday, used a
radio observatory in New Mexico and NASA’s Chandra X-ray Observatory
in space to identify when the supernova, or stellar explosion,
occurred. They put the star-dying event at some time around 1868.
Before now, the youngest supernova in the Milky Way was thought
to have occurred around 1680.
A supernova is the catastrophic explosion of a star that releases
an extraordinary amount of energy, enough to outshine an entire
galaxy.
The new baby supernova is located near the center of the galaxy
and obscured by dense gas and dust, making it virtually impossible
to see in optical light.
Two to three supernovae are thought to occur every century in the
Milky Way. As a result, there are probably even younger ones out
there waiting to be identified, said David Green of the University
of Cambridge in England, who led the radio observatory study.
Green and others have been tracking the remnant of the supernova
since 1985 via the National Science Foundation’s Very Large Array, a
radio astronomy observatory. But it was not until last year that a
team led by North Carolina State University physicist Stephen
Reynolds found with help from Chandra how much the remnant had
expanded. That indicated the supernova was much younger than initial
estimates ranging from 400 to 1,000 years old.
The Very Large Array made new observations in March and helped
pinpoint the age at 140 years, possibly less if the expansion has
been slowing.
“It’s the combination of the radio and the X-ray, the older
technique and the new one, that tells us what this object really is.
So you get a lot more when you put all of these clues together,”
said Robert Kirshner, a Harvard University astronomer who is not
affiliated with the study.
“It’s a little like one of those shows on TV where they
investigate a death. This is a stellar death, all right, and the
corpse is still warm,” Kirshner said during a teleconference with
reporters.
Astronomers typically observe supernova remnants that are 10,000
or so years old, not relative infants like this one. Getting the
total picture, from the start, is important in figuring out how
often supernovae explode in the Milky Way.
In this case, “you’re actually getting to see the rock that made
the splash, not the wave that’s going out into the pond,” Kirshner
said.(Associated Press Aerospace Writter)

Youngest supernova in Milky Way
by Jean-Louis Santini


WASHINGTON, May 14, 2008 (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 Sagitarius 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.
(js/fgf/ch US-astronomy-supernova AFP)

Yulvi Write :

Sungguh sangat tersentak ketika pagi ini saya membuka wirenews dari Kompas Wire Services, Kamis (15/5) ini. Di tengah dominasi berita domestik yang masih saja diwarnai isu kenaikan bahan bakar minyak (BBM) dan kebijakan bodoh Bantuan Langsung Tunai-nya pemerintah, dimana HL berita internasional masih menyoroti seputar gempa di China, mata dan pikiran saya justru tersita pada berita ini:"Baby Supernova in Our Neighborhood" yang diberitakan ramai oleh Reuters, AP, dan AFP. Bagi sebagian orang, mungkin ini tidak menarik. Tetapi,tidak demikian halnya bagi saya yang menyukai sains dan astronomi.
Adalah David Green dari Universitas Cambridge yang membuat penemuan heboh ini. Penelusurannya selama 15 tahun tentang dugaan keberadaan supernova termuda di Galaksi Bimasakti, sistem galaksi tempat bumi berpijak, terjawab sudah. G1.9+0.3, demikian nama supernova muda yang terletak di pusat Bimasakti itu. Ia berjarak 25.000 tahun cahaya dari Bumi...
Yang sungguh mengejutkan, kenapa dijuluki muda, karena berdasarkan pengamatan U.S. National Science Foundation’s Very Large Array (1985) hingga Stephen Reynolds dari North Carolina State University menggunakan piranti Chandra X-Ray Observatory (2007), umur supernova itu baru 140 tahun!!! Ledakan bintang mati ini diprediksi terjadi pada 1868....Seperti dilaporkan AFP, usianya jauh lebih muda dari penemuan terakhir supernova di Galaksi Bimasakti, tahun 1680....
Penemuan ini tentu menjadi tonggak sejarah baru dalam babak pengungkapan misteri supernova yang hingga kini masih belum banyak tersingkap...Menjadi modal berharga bagi para ilmuwan untuk mengungkap teori mati dan lahirnya bintang, pembentukan lubang hitam (blackhole) , dan tentu bisa jadi, teori pembentukan alam semesta....
Apalagi,letak dan peristiwa kejadiannya sangat berdekatan...Mari kita tunggu kabar dan kejutan berikutnya!!!!
viva sains