One-of-a-kind star discovered, nicknamed 'Nasty'--T-REC-komunitas reptil-semarang--KSE-komunitas satwa eksotik

SILAHKAN MENGGUNAKAN " MESIN TRANSLATE "..GOOGLE TRANSLATE
DISAMPING KANAN INI.............

PLEASE USE ........ "TRANSLATE MACHINE" .. GOOGLE TRANSLATE BESIDE RIGHT THIS

.................


T-REC -TUGUMUDA REPTILES COMMUNITY-INDONESIA


More info :
www.trecsemarang2011.blogspot.com
minat gabung : ( menerima keanggotaan seluruh kota dan daerah di Indonesia )
08995557626
..................................
KSE – KOMUNITAS SATWA EKSOTIK – EXOTIC PETS COMMUNITY-- INDONESIA
Visit Our Community and Joint W/ Us....Welcome All Over The World
www.facebook.com/groups/komunitassatwaeksotik/
 KSE = KOMUNITAS SATWA EKSOTIK

MENGATASI KENDALA MINAT DAN JARAK

KAMI ADA DI TIAP KOTA DI INDONESIA
DETAIL TENTANG KSE-----KLIK : www.komunitassatwaeksotik-pendaftaran.blogspot.com

GABUNG......... ( menerima keanggotaan seluruh kota dan daerah di Indonesia )
HUBUNGI   :  089617123865

.........................

One  -of - a-kind star  ditemukan , dan dijuluki ' Nasty '

Date:

May 21, 2015

Source:

Space Telescope Science Institute (STScI)

Summary:

Ringkasan :

Para astronom telah menghabiskan puluhan tahun mencoba untuk menentukan perilaku eksentrik dari sebuah bintang tua  yang dijuluki " Nasty 1 " yang berada di galaksi Bima Sakti kita . Melihat bintang menggunakan Hubble Space Telescope NASA , para astronom telah memperkirakan untuk melihat gas arus keluar bipolar lobus kembar  dari bintang . Para astronom terkejut , namun, untuk menemukan gas disk  berbentuk pancake  yang mengelilingi bintang. Disk yang luasnya  hampir 1.000 kali diameter tata surya kita ....read more

One-of-a-kind star discovered, nicknamed
'Nasty'

Date:

May 21, 2015

Source:

Space Telescope Science Institute (STScI)

Summary:

Astronomers have spent decades trying to determine the oddball behavior of
an aging star nicknamed "Nasty 1" residing in our Milky Way galaxy.
Looking at the star using NASA's Hubble Space Telescope, astronomers had
expected to see a bipolar outflow of twin lobes of gas from the star. The
astronomers were surprised, however, to find a pancake-shaped disk of gas
encircling the star. The vast disk is nearly 1,000 times the diameter of our
solar system.

.......................

This visible-light image taken by NASA's Hubble Space Telescope reveals a
pancake-shaped disk of gas around an extremely bright star in our Milky Way
galaxy. The disk glows brightly in the light of ionized nitrogen. The central
star is nicknamed "Nasty 1," derived from its catalog name of NaSt1.
Nasty 1 is thought to be a Wolf-Rayet star, a massive, rapidly evolving star
weighing well over 10 times the mass of our sun. The star is losing its
hydrogen-filled outer layers quickly, exposing its super-hot and extremely
bright helium-burning core. Nasty 1 is thought to have a companion, and
gravitational interactions between them may have created the gas disk. Both stars
are heavily obscured by gas and dust in the disk. Hubble observations suggest
that as Nasty 1 sheds its weight, some of the mass is falling onto a companion
star and some is leaking into space, forming the disk. The vast structure is
nearly 2 trillion miles wide. The disk is clumpy because astronomers think the
outbursts occur sporadically. The knot at left of center is an unusually bright
clump of gas. The image is tinted blue to bring out details in the disk.
Astronomers were surprised to find the disk-like structure, which has never
been seen before around a Wolf-Rayet star in our galaxy. The star may represent
a brief transitory stage in the evolution of massive stars. The Nasty 1 system
may be as close as 3,000 light-years from Earth. The observations were taken in
April 2013 with the Wide Field Camera 3.

Credit: NASA, ESA, and J. Mauerhan (University of California, Berkeley)

Astronomers using NASA's Hubble Space Telescope have uncovered surprising
new clues about a hefty, rapidly aging star whose behavior has never been seen
before in our Milky Way galaxy. In fact, the star is so weird that astronomers
have nicknamed it "Nasty 1," a play on its catalog name of NaSt1. The
star may represent a brief transitory stage in the evolution of extremely
massive stars.

First discovered several decades ago, Nasty 1 was identified as a
Wolf-Rayet star, a rapidly evolving star that is much more massive than our
sun. The star loses its hydrogen-filled outer layers quickly, exposing its
super-hot and extremely bright helium-burning core.

But Nasty 1 doesn't look like a typical Wolf-Rayet star. The astronomers
using Hubble had expected to see twin lobes of gas flowing from opposite sides
of the star, perhaps similar to those emanating from the massive star Eta
Carinae, which is a Wolf-Rayet candidate. Instead, Hubble revealed a
pancake-shaped disk of gas encircling the star. The vast disk is nearly 2
trillion miles wide, and may have formed from an unseen companion star that
snacked on the outer envelope of the newly formed Wolf-Rayet. Based on current
estimates, the nebula surrounding the stars is just a few thousand years old,
and as close as 3,000 light-years from Earth.

"We were excited to see this disk-like structure because it may be
evidence for a Wolf-Rayet star forming from a binary interaction," said
study leader Jon Mauerhan of the University of California, Berkeley.
"There are very few examples in the galaxy of this process in action
because this phase is short-lived, perhaps lasting only a hundred thousand
years, while the timescale over which a resulting disk is visible could be only
ten thousand years or less."

According to the team's scenario, a massive star evolves very quickly, and
as it begins to run out of hydrogen, it swells up. Its outer hydrogen envelope
becomes more loosely bound and vulnerable to gravitational stripping, or a type
of stellar cannibalism, by the nearby companion star. In that process, the more
compact star winds up gaining mass, and the original massive star loses its
hydrogen envelope, exposing its helium core to become a Wolf-Rayet star.

Another way Wolf-Rayet stars are said to form is when a massive star ejects
its own hydrogen envelope in a strong stellar wind streaming with charged
particles. The binary interaction model where a companion star is present is
gaining traction because astronomers realize that at least 70 percent of
massive stars are members of double-star systems. Direct mass loss alone also
cannot account for the number of Wolf-Rayet stars relative to other
less-evolved massive stars in the galaxy.

"We're finding that it is hard to form all the Wolf-Rayet stars we
observe by the traditional wind mechanism, because mass loss isn't as strong as
we used to think," said Nathan Smith of the University of Arizona in
Tucson, who is a co-author on the new NaSt1 paper. "Mass exchange in
binary systems seems to be vital to account for Wolf-Rayet stars and the
supernovae they make, and catching binary stars in this short-lived phase will
help us understand this process."

But the mass-transfer process in mammoth binary systems isn't always
efficient. Some of the stripped matter can spill out during the dynamical
gravitational tussle between the stars, creating a disk around the binary.

"That's what we think is happening in Nasty 1," Mauerhan said.
"We think there is a Wolf-Rayet star buried inside the nebula, and we
think the nebula is being created by this mass-transfer process. So this type
of sloppy stellar cannibalism actually makes Nasty 1 a rather fitting
nickname."

The star's catalog name, NaSt1, is derived from the first two letters of
each of the two astronomers who discovered it in 1963, Jason Nassau and Charles
Stephenson.

Viewing the Nasty 1 system hasn't been easy. The system is so heavily
cloaked in gas and dust, it blocks even Hubble's view of the stars. So
Mauerhan's team cannot measure the mass of each star, the distance between
them, or the amount of material spilling onto the companion star.

Previous observations of Nasty 1 have provided some information on the gas
in the disk. The material, for example, is travelling about 22,000 miles per
hour in the outer nebula, slower than similar stars. The comparatively slow
speed indicates that the star expelled its material through a less violent
event than Eta Carinae's explosive outbursts, where the gas is travelling
hundreds of thousands of miles per hour.

Nasty 1 may also be shedding the material sporadically. Past studies in
infrared light have shown evidence for a compact pocket of hot dust very close
to the central stars. Recent observations by Mauerhan and colleagues at the
University of Arizona, using the Magellan telescope at Las Campanas Observatory
in Chile, have resolved a larger pocket of cooler dust that may be indirectly
scattering the light from the central stars. The presence of warm dust implies
that it formed very recently, perhaps in spurts, as chemically enriched
material from the two stellar winds collides at different points, mixes, flows
away, and cools. Sporadic changes in the wind strength or the rate the
companion star strips the main star's hydrogen envelope might also explain the
clumpy structure and gaps seen farther out in the disk.

To measure the hypersonic winds from each star, the astronomers turned to
NASA's Chandra X-ray Observatory. The observations revealed scorching hot plasma,
indicating that the winds from both stars are indeed colliding, creating
high-energy shocks that glow in X-rays. These results are consistent with what
astronomers have observed from other Wolf-Rayet systems.

The chaotic mass-transfer activity will end when the Wolf-Rayet star runs
out of material. Eventually, the gas in the disk will dissipate, providing a
clear view of the binary system.

"What evolutionary path the star will take is uncertain, but it will
definitely not be boring," said Mauerhan. "Nasty 1 could evolve into
another Eta Carinae-type system. To make that transformation, the mass-gaining
companion star could experience a giant eruption because of some instability
related to the acquiring of matter from the newly formed Wolf-Rayet. Or, the
Wolf-Rayet could explode as a supernova. A stellar merger is another potential
outcome, depending on the orbital evolution of the system. The future could be
full of all kinds of exotic possibilities depending on whether it blows up or
how long the mass transfer occurs, and how long it lives after the mass
transfer ceases."

The team's results will appear May 21 in the online edition of theMonthly
Notices of the Royal Astronomical Society.







Story Source:

The above story is based on materials provided by Space
Telescope Science Institute (STScI). Note: Materials may be edited
for content and length.







Journal Reference:

1.   
Jon C. Mauerhan, Nathan Smith, Schuyler D. Van Dyk, Katie M. Morzinski,
Laird M. Close, Philip M. Hinz, Jared R. Males, Timothy J. Rodigas. Multiwavelength
Observations of NaSt1 (WR 122): Equatorial Mass Loss and X-rays from an
Interacting Wolf-Rayet Binary. The Monthly Notices of the Royal
Astronomical Society, 2015 [link]

http://www.sciencedaily.com/releases/2015/05/150521133517.htm

Share this: