The Suspect: WR 104....
So what kind of star could do this to us?
It's called a Wolf-Rayet
star, and they are a special kind of star. They are a massive
star (over 20 solar masses) which are losing that mass rapidly by means of a strong stellar wind.
Our own sun looses 10^-14 (0.00000000000001) solar masses every year. Where as a Wolf-Rayet star looses 10^-5 (0.00001) solar masses each year.
Wolf-Rayet stars are also very hot, with surface temperatures in the range of 30,000 K to 200,000 K. They are also very bright, having up to several
million times the bolometric luminosity of our sun. They are not visually bright, but bright in the ultraviolet to X-ray range.
However, because of their mass, when they are on the verge of dying, they collapse in on themselves, and if they do not loose enough mass, they can
create what we call a collapsar.
When a collapsar forms, two jets of gamma ray energy are emitted along the axial poles of the star. These jets have been associated with what we have
come to call GRBs or Gamma Ray Bursts.
Gamma Ray Bursts are the most powerful forms of energy that we have ever recorded. GRBs have been recoreded by us from billions of light years away.
The amount of energy it has in the few seconds that it exists is more than all the energy our sun will put out in it's 10 billion year life span.
There are two types of GRBs: Long and Short. The distinction is that Long GRBs last for more than 2 seconds, where as Short GRBs last for less than
GRBs produced from Wolf-Rayet stars are Long GRBs.
So just how many of these stars are there? Are there any in our galaxy?
GRBs that we have recoreded have originated outside our galaxy. Once it was realized what type of star can make these, astronomers looked.
They found that Wolf-Rayet stars in our galaxy are actually rare.
Before you breath a sigh of relief, let me explain what I mean by "rare". I mean "rare" as in there are about 500 of these types of stars in our
galaxy that we have found so far. Considering the amount of stars we have in our galaxy (somewhere between 200 billion to 400 billion), that makes
However, rare or not, we have one near by, at about 8,000 light years away. It's designation is WR
It should be noted that not every Wolf-Rayet star would end up becoming a collapsar. There are several sub designations for Wolf- Rayet stars.
Unfortunately, WR 104 is one that has been classified as one that could produce a GRB.
So, information on WR 104:
Located in the constellation Sagittarius, RA 18h 02m 04.7s, Dec -23 deg 37' 41.2"
Mass: 25 suns
radius: 3 x sun
WR 104 is a Wolf-Rayet star discovered in 1998, located 8,000 light years from Earth. It is a binary star with a class OB companion. The stars
have an orbital period of 220 days and the interaction between their stellar winds produce a spiral "pinwheel" outflow pattern over 200 astronomical
units long. The spiral is composed of dust that would normally be prevented from forming by WR 104's intense radiation were it not for the star's
The problem is: we have too many "If's", "Maybe's" and "If We Assume"s when it comes to WR 104.
Even though it's been studied since 1998, it's hard to refine information on a object that is 8,000 light years away. It seemed when first looking at,
that it's axial spin lay within 16 deg of Earth.
That gave a lot of astronomer's and astrophycists pause. Having it's poles pointed that close to Earth means that we were looking directly down the
barrel of a GRB.
The other reason for concern is that WR 104's evolution is almost over. It's ready to die, and die soon.
How soon? Could be 100 years from now. Or it could be tomorrow. That's the problem, as there is no way to know exactly for sure.
However, before you panic, there is good news. New spectroscopic data suggests that WR 104's rotational axis is more likely at a 30 to 40 deg angle
from our planet. That means the barrel is pointed enough away from us that we would not be in any danger.
It's also never been a certainty that WR 104 would produce a GRB either. The only examples we have are from GRBs in other galaxies, measureing in the
millions to billions of light years away.
So even if WR 104 were to go hypernova on us tomorrow it would seem that the worst we could expect is radiation slamming in to things that are out in
space (satellites, probes, etc), but it would not hurt our ozone much and we would be okay (appart from having a cool light show).
Hope some found this interesting.
edit on 8-6-2013 by eriktheawful because: (no reason given)
edit on 8-6-2013 by eriktheawful
because: (no reason given)