Neutron stars are the ultra-dense remnants of collapsed stars. Not really wider than a small town, they weigh much more than our own Sun. Scientists also call them pulsars, because when we observe these objects with telescopes they appear as sources of pulsating light. Most rotate much faster than normal stars, and their regular rotations can act like clocks in space.
Now an international team of astronomers has discovered what are known in astronomy as the black widow spider and red-backed spider stars in space.
Why this denomination?
Although these objects do not actually eat their companions, they do share the characteristic violent behavior of these eight-legged land arachnids . As if this were not enough, in addition to the mentioned spider stars, the researchers, who used the now defunct (after its collapse) Arecibo telescope in Puerto Rico, also discovered a strange cross between black widow and red back that defies this already in itself. unusual categorization. It is a cross between the two species of spider stars.
Spider stars?
Spider stars are, therefore, types of pulsars or neutron stars that rotate at least once every 30 milliseconds and, in each rotation, show flashes as if it were a lighthouse, making us feel that the stars pulse or beat like a cosmic heart.
Neutron stars can pluck material from smaller stars that are in binary orbits with them, and use that material that falls into them to achieve pulsar speed. The difference between a common neutron star and a spider star is that the latter represent the rarest, most unique and special version of these particular stars : they orbit so close to their binary companions that they destroy their surface, inhaling large amounts of material like a spider. that devours the male limb by limb (remember that the spiders of the Latrodectus genus are the ones that have the fame of eating the male after copulation, although they are not the only ones).
How to tell the difference between spider stars
Black widow spider star: when the star has managed to reduce its companion to less than one tenth of the mass of the Sun (usually 0.02 to 0.03 times the mass of the Sun).
Red-backed spider star: when the object that is being eaten by the spider star has more than one tenth of the solar mass. These binary companions pass between the spider star and Earth periodically, creating temporary eclipses. In the case of the black widow spider star, its “victims” do not usually make this journey.
New Kind of Black Widow / Redback Mixed Star: Astronomers are finding it difficult to classify. At the moment, it’s being labeled a red-backed spider star because its companion, with a mass at least 0.055 times the mass of the sun (or possibly larger), sometimes overshadows its ticking. But it is still too much matter for a black widow spider star and too light for a red-backed spider star. It is clear that, for now, it is a cosmic mystery.
Referencia: Timing of Eight Binary Millisecond Pulsars Found with Arecibo in Fermi-LAT Unidentified Sources, arXiv:2012.15185 [astro-ph.HE] arxiv.org/abs/2012.15185
