Half of the stars in our galaxy are lone stars, like the Sun, and the other half are stars that form star systems that rotate in pairs or groups, some with orbits so narrow that it could be between the Earth and the Moon.
Now, a team led by the Massachusetts Institute of Technology (MIT) discovered a pair of binary stars with an extremely short orbit: They rotate around each other every 51 minutes.
The newly discovered system, which the team gave its name ZTFJ1813 + 4251has the shortest orbit recorded to date.
the discovery, published in the journal Natureit was created in collaboration with Harvard University and the Smithsonian Center for Astrophysics, among other institutions.
The system appears to be one of the rare binary classes called “cataclysmic variables”where a Sun-like star orbits a white dwarf (the hot, dense core that remains of a star after it runs out of fuel).
These catastrophic variables arise when, in a process that spans billions of years, the two stars get close, causing the white dwarf begins to “eat” material from its companion star.
Astronomers have captured this catastrophic variable while the stars eclipsed each otherwhich helped to accurately measure its properties.
Using the measurements, they ran simulations of what the system is likely to do today and how it should evolve over the next few years. hundreds of millions of years.
According to their calculations, both stars are in transition, and the Sun-like star has turned in a circle and “donating” much of its hydrogen atmosphere to the ravenous white dwarf.
Over time, the sun-like star it will eventually shrink to a mostly dense, helium-rich core. And in 70 million years, the two will get even closer, to an ultra-short orbit of 18 minutes, before starting to expand and drift apart.
Although researchers at MIT and elsewhere predicted decades ago that these catastrophic variables would shift to ultrashort orbits, this is the first time it has been directly observed.
“People foresaw that these objects would pass on to ultrashort orbits, and it has long been debated whether they could be shortened enough to emit detectable gravitational waves. This discovery puts an end to the debate, “he explains Kevin Burge of MIT.
To do the study, Burdge used the catalog of stars observed since Transitional structure of Zwicky (ZTF)using a camera attached to a telescope in the California Palomar Observatory to acquire high-resolution images of large swaths of the sky.
Burge searched stars that seem to shine repeatedly, with a period of less than an hour, a frequency that typically signals a system of at least two objects in close orbit, one passing the other and briefly blocking the light.
the astronomer has chosen more than a billion stars and a selected algorithm close to a million that seemed to flash every hour or so.
Among these, Burdge looked for signs of particular interest and focused on ZTF J1813 + 4251, a system that is about 3,000 light-years from Earth, in the constellation of Hercules.
“this thing appearedwhere I would see an eclipse occur every 51 minutes and say, ok, this is definitely a binary, ”Burdge recalls.
The authors observed the system with the WM Keck Observatory in Hawaii and the Gran Telescopio Canarias in Spain and found that the system It allowed an accurate measurement of mass.the radius of each star and its orbital period.
Thus, they found that the first object was probably a white dwarf, with one hundredth of the size of the sun and about half of its mass, and the second a star similar to the Sun, almost at the end of its life and similar in size to Jupiter.
Burdge realized that ZTF J1813 + 4251 was probably a cataclysmic variable, in the act of moving from a hydrogen-rich to a helium-rich body, a discovery that confirms previous predictions. EFE
Source: Clarin
