About 5,000 light years away, the Boomerang
Nebula is the coldest object known.
Works Cited
Thursday, March 20, 2014
Big Bang Confirmed?
Not exactly. However, as new studies have found, new ripples of cosmic microwave background may gives us more insight on the true details of the occurrences during the big bang.
Check out the articles below.
Works Cited
Check out the articles below.
Works Cited
Eta Carinae
Eta Carinae is a stellar system in the constellation Carina. It is located
about 7,500 to 8,000 light years away from Earth (so its parallax angle is
about 0.435 to 0.408 micro arc seconds since 1 parsec = 3.262 light years) with
a mass equivalent to that of about 100 solar masses. Its luminosity is known to
be about a million times brighter than the sun! It is currently one the biggest
and brightest stars in our galaxy. Astronomers who have studied its history and
its present conditions suspect it to be a major supernova candidate that could
erupt any day now.
History
In the 19th century, its apparent brightness dramatically
increased for two decades, then decreased. This period of time was known as the
“great eruption.” No one is absolutely sure on the cause of this eruption. Also
parts of the cloud of dust and gas in the two big globes that surround it today
are believed to have been released during this dramatic increase in brightness.
In 1843 it flared up and became the second brightest star in the sky, after
Sirius. It remained this way for about 20 years and then faded, leaving a cloud
of gas called the Homunculus Nebula. Eta Carinae has lost about 10% of its substance
during that event. Astronomers have called this a “supernova impostor.” After
this it returned to be quiet, for an unstable object that is.
From 1976 to 1998, astronomers observed start the South African
Astronomical Observatory. During this period of time, they saw an increase
across the J, H, K, and L bands, which are filters that allow certain infrared
light to pass. However, the reason for this increase in infrared light was
unknown at the time.
More Recently
After 1988, the brightness increased more rapidly than a linear trend in
the J and H bands. Although this would typically lead observers to believe it
is getting hotter, it’s highly unlikely that this is the cause of rapid brightness
increase. One theory is that the cloud of dust absorbs blue light, so it is safe
to say that this increase could just be the star’s actual brightness, seeing as
how the dust could merely be getting destroyed. However this expansion of the
cloud that surrounds Eta Carinae is not enough to account for the brightening.
Instead it is possibly losing its mass or rotating at a different speed.
In 2005, astronomers discovered that Eta Carinae has at least one
companion star. The more massive star, Eta Carinae A, is a blue star. The
increase in temperature was most likely due to an overall
increase in temperature of some component of the Eta Carinae system, which
includes the cloud of dust and gas that surround the massive star.
Although this star has been studied so much by several types of telescopes,
there is no theory that has explained what happened.
These changes have lead scientists to believe that the star is becoming
more unstable and may be headed towards another eruptive phase, perhaps a
second “great eruption.”
Fate
If Eta Carinae does indeed blow up into a supernova, would we be
affected? Luckily for us, since we are about 7500 light years away, the
radiation from the supernova would not be able to reach us.
These along with many others, are reason astronomers believe Eta Carinae
to be a candidate for the next supernova to occur within our galaxy. Especially
since there was a star in another galaxy that also seemed like a “supernova
impostor” but then a few year later, boom
This star is heading towards instability and eruption and when it goes
off it will create a blast so violent that its flash will briefly outshine the
entire Milky Way.
Works Cited
Wikipedia: http://en.wikipedia.org/wiki/Eta_Carinae
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