Astronomers have discovered a binary star system with the shortest orbits of binary stars ever discovered, as it only takes 51 minutes for one to orbit the other, according to RT.
This system appears to be one of the rare classes of binary star systems known as “catastrophic variable” (seminova), in which a star similar to our Sun orbits closely around a white dwarf, the hot and dense core of a star.
The “catastrophic variable” occurs when two stars approach each other over the course of billions of years, causing the white dwarf to start crashing into its partner, or devouring material from the partner star’s explosions.
This process can produce gigantic and variable flashes of light that astronomers assumed centuries ago were the result of an unknown cataclysm.
The “catastrophic” system, located about 3,000 light years from Earth in the constellation of Hercules, has the shortest orbit of its kind ever discovered.
Astronomers from the Massachusetts Institute of Technology made the discovery, which they named ZTF J1813 + 4251.
Unlike other systems observed in the past, experts have discovered this “catastrophic variable” in which stars mask each other multiple times, allowing the team to accurately measure the properties of each star.
Then they ran simulations of what the system is likely to do today and how it is expected to evolve over the next hundreds of millions of years.
This has led scientists to theorize that stars are currently in transition and that the sun-like star rotates and donates much of its hydrogen envelope to the insatiable white dwarf.
Over time, astronomers say, the sun-like star will eventually be ripped off into a dense, helium-rich core.
After another 70 million years, the two stars will migrate close to each other, with an extremely short orbit of only 18 minutes, before starting to expand and recede.
Decades ago, scientists at MIT and elsewhere predicted that these catastrophic variables would travel on ultrashort orbits, but this is the first time such a transition system has been directly observed.
“This is a rare case where we discovered one of these systems during the transition process from hydrogen to helium accumulation,” said Kevin Bridge, of the MIT Department of Physics.
People expected these objects to travel in ultrashort orbits, and for a long time it was debated whether they could become short enough to emit detectable gravitational waves.
Bridge and colleagues discovered the new system in a large catalog of stars monitored by the Zwicky Transient Facility (ZTF), an investigation that uses a camera attached to a telescope at the Palomar Observatory in California to capture high-resolution images of large areas of the sky. .
The survey captured more than 1,000 images of each star from more than a billion stars in the sky, recording the varying brightness of each star over the course of days, months and years.
Berridge scoured the catalog, looking for signs of ultrashort orbital systems, whose dynamics can be so intense that they have to fire dramatic bursts of light and emit gravitational waves.
These appear to flash frequently (with a period of less than an hour), frequencies that usually indicate a system of at least two orbiting bodies, one intersecting with the other and briefly blocking the light.
Berridge used an algorithm to get rid of over a billion stars, each recorded in more than 1,000 images and eventually identified as ZTF J1813 + 4251.
“This system came up, where I saw an eclipse that happened every 51 minutes and I said, OK, it’s definitely binary,” Bridge explained.
Scientists have found that the first object is likely a white dwarf, 1/100 the size of the sun and about half its mass.
The second was a sun-like dying star, about one-tenth the size and mass of the sun (about the size of Jupiter).
Although this star is similar to the sun, but the sun cannot re-enter an orbit of less than eight hours, so scientists realized that ZTF J1813 + 4251 was most likely a “catastrophic variable”, a discovery which means it is the shortest “catastrophic variable” orbit that has been discovered so far.
