Open the biggest star


22/07/2010

With the help of the instrument cluster, astronomers from the European Southern Observatory (ESO), opened the most massive stars known to date. One of them weighs 300 mass of our Sun, which is two times greater than the mass of 150 suns, which used to be an absolute weight limit star. These cosmic monsters, which are millions of times brighter than the sun, may help to answer the question "how massive can stars be?".

This discovery made the team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield. They used a telescope called the Very Large Telescope (VLT), as well as historical data NASA / ESA, for a detailed study of two young clusters of stars called NGC 3603 and RMC 136a.

The team managed to find a few stars, the surface temperature of more than 40,000 degrees. They are seven times as hot a few tens of times larger and several million times brighter than our sun. The simulated models allow us to say that the weight of some of these stars at birth greater than the mass of the sun is 150 times. Star R136a1, found in the cluster, R136, is the most massive star ever discovered. Her weight at the moment is equal to 256 suns masses, and at birth, her weight was equal to the mass of 320 suns.

But the more the star, the faster it loses mass. "Unlike humans, stars are born big and lose weight as they age," - said Paul Crowther. "The biggest star discovered R136a1, are over a million years - the average age for a star. Could say that during this time, the star was an intensive program for sgonke weight, dropping one-fifth of its original weight, or more than 50 solar masses."

If the star R136a1 replaced the Sun in our Solar System, it would have been just as brighter than the sun as the sun brighter than the full moon. "The large mass of the star, will reduce the duration of Earth year to three weeks, and it just will flood the Earth is incredibly intense ultraviolet radiation, making life impossible on our planet," - said Raphael Hirschi from Keele University, which is one of the team members.

These heavy stars are very rare, they appear only in the depths of a very dense clusters. Detection of individual stars, which today has been achieved for the first time requires the use of extremely thin devices to operate in the infrared.

The team was able to calculate the maximum possible mass for the stars within these clusters and the relative number of the most massive stars. "The smallest stars can not have a mass of less than 80 Jupiter masses low weight make them" failed stars’ or brown dwarfs, "- said a member of the team, Oliver Sknur, of the Astrophysical Institute in Potsdam. "Our latest discoveries suggest that there is an upper limit for the maximum value of the stars, even though we have increased the limit twice, up to 300 solar masses."

Inside the cluster R136, only four stars weighed at birth more than 150 solar masses, and, nevertheless, they emit half the space of wind and radiation of the entire cluster, which consists of a total of about 100,000 stars. The energy that emits the closest to the Earth formation of massive stars - the Orion Nebula, more than 50 times less than the energy of the emitted cluster R136a1.

In this image shows the ratio of the masses of the stars. The smallest "red dwarf" weighs 0.1 solar masses, "yellow dwarf" the size of our sun, "blue dwarf" weighs eight times larger than the sun, and the star R136a1 weighs 300 times more than the sun. Images are copyrighted by ESO / M. Kornmesser

Now scientists face the problem of determining the mechanism of nucleation and formation of giant stars. "Either they were born so big right away, or formed by the merger of several smaller stars," - said Crowther.

Stars of mass in the 8-150 explode at the end of his short life as a supernova, leaving remnants such as neutron stars and black holes.

R136a1 is not only the biggest star of the detected to date, it is also the brightest - about 10 million times brighter than the Sun. "These monsters are rare, so I do not think that in the near future, this record will be broken," - concluded Crowther. Only the first news portal tells about the events of the day.

Original: Physorg.com


Traces of life may conceal the clay in the deep craters on Mars
Astronomers have discovered the sleeping and waking galaxy
Two tiny asteroid zipped past Earth
Asteroid Apophis will fly past Earth in 2036
India rushes into space