Many stars are known to be “variable” or “pulsating”, but a Swiss team of astronomers has discovered a new type of these stars with changing light.
This discovery, published Wednesday in the journal “Astronomy and Astrophysics”, based on regular measurements of more than 3000 stars in the cluster NGC 3766, a period of seven years. It was conducted by a team of astronomers from Geneva with the Swiss Euler telescope, installed at the La Silla Observatory (Chile) belonging to the European Southern Observatory (ESO).
In this cluster, the team Nami Mowlavi discovered, for the first time, a group of 36 stars with “tiny variations in their luminosity, of the order of 0.1% of normal brightness of stars” ESO said in a statement. The frequency of these variations is between two and twenty hours.
These stars of a new type, which has no name yet, “are slightly warmer and brighter than the sun,” said ESO.
“The very existence of this new class of variable stars is a challenge for astrophysicists,” said Sophie Saesen, a team of astronomers. “The current theoretical models predict that their light is not supposed to vary periodically, so our efforts are to better understand the behavior of this new type of star.”
The origin of their variation remains unknown, but astronomers have observed that some seem to be equipped with a rapid turnover. They run at speeds equivalent to more than half of “critical speed”, the threshold at which the stars become “unstable” and eject their material into space.
“Under these conditions, the rapid rotation will have a significant impact on their internal properties, but we are not yet able to model the variations in brightness,” said Nami Mowlavi.
The study of variations in brightness or pulsating variable star gave birth to a whole new branch of astrophysics, asteroseismology.
This discovery, published Wednesday in the journal “Astronomy and Astrophysics”, based on regular measurements of more than 3000 stars in the cluster NGC 3766, a period of seven years. It was conducted by a team of astronomers from Geneva with the Swiss Euler telescope, installed at the La Silla Observatory (Chile) belonging to the European Southern Observatory (ESO).
MY ACTIVITY
Your friends can now see this activity Delete X
In this cluster, the team Nami Mowlavi discovered, for the first time, a group of 36 stars with “tiny variations in their luminosity, of the order of 0.1% of normal brightness of stars” ESO said in a statement. The frequency of these variations is between two and twenty hours.
These stars of a new type, which has no name yet, “are slightly warmer and brighter than the sun,” said ESO.
“The very existence of this new class of variable stars is a challenge for astrophysicists,” said Sophie Saesen, a team of astronomers. “The current theoretical models predict that their light is not supposed to vary periodically, so our efforts are to better understand the behavior of this new type of star.”
The origin of their variation remains unknown, but astronomers have observed that some seem to be equipped with a rapid turnover. They run at speeds equivalent to more than half of “critical speed”, the threshold at which the stars become “unstable” and eject their material into space.
“Under these conditions, the rapid rotation will have a significant impact on their internal properties, but we are not yet able to model the variations in brightness,” said Nami Mowlavi.
The study of variations in brightness or pulsating variable star gave birth to a whole new branch of astrophysics, asteroseismology.
No comments:
Post a Comment