M.Weiss is the director of the Center for Astrophysics.
A new type of star has been observed by researchers at the Center for Astrophysics. A rare type of star in the universe is confirmed by the discovery.
The new class of stars was discovered by a fellow researcher using a telescope in California and data from several surveys.
"We have seen the first physical proof of a new population of transitional stars," says El- Badry. This is exciting because it's a missing evolutionary link in the models we've been looking for.
A new type of star.
There is a 97 percent chance that a star will become a white dwarf after it dies.
A star can become a white dwarf in rare instances. If stellar evolution calculations are correct, the stars are older than the age of the universe itself and thus, physically impossible.
El-Badry is a member of the Institute for Theory and Computation at the Center for Astrophysics.
Astronomers have concluded that the only way for an ELM white dwarf to form is with a companion. The star could be eaten away by a nearby companion star in less than 13B years.
There is evidence for this picture.
Astronomers have observed normal, massive stars like our Sun accretion onto white dwarfs. They have seen ELM white dwarfs with their white dwarf companions. They did not observe the transition phase of evolution, when a star has lost most of its mass and is almost a white dwarf.
A missing link.
El-Badry compares stellar astronomy to 19th century zoology.
You go into the jungle and find something. He explains that you describe how big it is, how much it weighs, and then you go on to other organisms. You need to piece together how all these different objects are connected.
In 2020, El-Badry decided to go back into the jungle in search of the pre-ELM white dwarf, a star that had long been referred to as an evolved cataclysmic variable.
El-Badry narrowed down the number of stars to 50 using new data from the European Space Agency and the Caltech Transient Facility.
The astronomer uses public data from surveys for his work. "If it weren't for projects like the Zwicky Transient Facility and Gaia, this work wouldn't be possible," he says.
El-Badry followed with close observations of 21 stars.
The strategy worked. He says that 100 percent of the candidates were pre-ELMs. They were more bloated and puffed up than ELMs. They were shaped like eggs because of the pull of the other star.
"We found a link between the two classes of stars, and we found a good number of them," El-Badry says.
Thirteen of the stars showed signs that they were still losing mass to their companion, while eight of the stars seemed to no longer be losing mass. They were hotter in temperature than previously observed variables.
El-Badry will continue to study the pre-ELM white dwarfs and possibly follow up on the other candidates he discovered.
He is amazed by the diversity of stars that can be created from simple science.
The Birth of the ELMs: a ZTF survey for evolved cataclysmic variables turning into extremely low-mass white dwarfs was published in the Monthly Notices of the Royal Astronomical Society. There is a DOI of 10.093/mnras/stab2583.
There are monthly Notices of the Royal Astronomical Society.
Astronomers observe a new type of star that was predicted to exist in December.
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