July 26, 2012 Leave a Comment
An international team of scientists in Chile have begun to study what are known as “O-type” stars, which have very high temperature, mass, and brightness. These stars live short and violent lives and play a key role in the evolution of galaxies. They also are linked to extreme phenomena, such as “vampire stars” where a smaller companion star sucks matter off the surface of its larger neighbor.
These vampire stars have 15 or more times the mass of our sun, and can be up to a million times brighter. The stars are so hot that they shine with an extreme blue-white light, and have surface temperatures close to 30,000 degrees celsius. The team of scientists analyzed the light coming from these vampire stars and discovered that 75 percent of all O-type stars exists inside binary systems, a higher proportion than previously thought.
O-type stars make up just a fraction of a percent of the stars in the universe. Violent phenomena are usually associated with these stars, which means they have a disproportionate effect on their surroundings. It is said that the winds and shocks coming from these stars can both trigger and stop star formation. The supernovae of these stars enrich galaxies with the heavy elements crucial for life. They are also associated with gamma-ray bursts, which are among the most energetic phenomena in the universe. Because of all of these characteristics, O-type stars are implicated in many of the mechanisms that drive the evolution of galaxies.
In the case of vampire stars, the smaller, lower-mass star is rejuvenated as it sucks the fresh hydrogen from its companion. It’s mass will increase substantially, and it will outlive its companion star. The victim star is stripped down before it has a chance to become a luminous red super giant. Instead, its hot, blue core is exposed. Both the rejuvenated vampire stars, and the diminished victim stars become hotter, and bluer in color, mimicking the appearance of younger stars.