A team of astronomers from Massachusetts Institute of Technology (MIT) just discovered a new black widow. A finding of this type may seem unusual for professionals with this specialty. But it is not about the famous spider, nor about the Marvel character. Actually, it’s a kind of star that spins very fast while engulfing a companion star. Just like the spider with her partners.
This is not the first time such a phenomenon has been observed. In fact, at least a couple of dozen of them are already known. stellar black widows. However, this one is special for two reasons. On the one hand, because the stars rotate with the shortest orbital period observed in pairs of this type. And, on the other, because it seems that there is a third star that revolves around themlike a voyeur who approaches to observe the tragedy.
This curious black widow has been described in a study recently published in Naturewhich also explains a new method for detect similar phenomena. And it is that, unlike in previous cases, these scientists have not focused on the signals of the hunter, but on those of the prey.
New methods to find the black widow of the stars
Before talking about black widows we should remember what the pulsarssince they constitute a fundamental part of the pair of stars.
These are neutron stars that rotate very fast on themselves, emitting very intense radiation based on gamma rays and x-rays. As they rotate they run out of fuel, hence they end up dying quickly. However, it may be the case that grasp another nearby star and attract it to them, stealing some of the matter that they will recycle to continue to exist. Therefore, it can be roughly said that eat to your couple. Like a black widow
They are usually located by x-ray and gamma ray detection emitted by the pulsar. However, the authors of the study that was just published thought that perhaps the swallowed star could also have something to say. The party facing the black widow receives a high radiation, to the point of being thousands of times hotter than the opposite side. Therefore, if they measured visible light, they could also find clues to the presence of this curious couple.
To do so, they took wide-field images of the sky, taken at the observatory Zwicky Transient Facility, in California. His goal was to look for stars whose brightness changed dramatically by a factor of 10 or more on a time scale of an hour or less. In words of one of the authors of the study, kevin burgeinstead of looking for the pulsar, they wanted to find the star that it “was cooking”.
But first they had to check if this method works for spot black widows, so they looked for some of those that have been previously detected. They managed to locate twelve, so it seemed that the technique was effective, so they used it to scan the sky for something new. That’s how they came up with ZTF J1406 + 1222.
Two great peculiarities of these stars
At least two dozen known black widows in the milky way. However, this one presents two peculiarities that the others do not have: its orbital period and a third star.
The orbital period is the shortest of any previously detected black widow, as the pulsar and its companion circle each other every 62 minutes. Instead, the third star detected by these MIT scientists circles around it every 10,000 years.
However, it would be necessary to study this star voyeur in greater depth to ensure both its period and that it actually orbits the black widow. Either way, it’s a very special find, not only because it has added another candidate to the list of these space gobblers, but because scientists now have a new way to find them. Who knows? Perhaps from now on its discovery will become something much more common.