Neutron star light – or something completely different?
Stars that are at least about three times heavier than the sun suffer a spectacular end. They manage to use all elements up to iron as fuel in different shells in their interior. Their core, which is only 10,000 kilometers across, then usually consists of iron and heavier elements. What happens to the dying star now depends mainly on this core. When it exceeds the Chandrasekhar limit of 1.44 solar masses, its matter can no longer resist its own gravity - and the star collapses into a neutron star. (more…)
Fluffy planet orbits a cool red dwarf star
Astronomers using the 3.5-meter WIYN telescope at Kitt Peak National Observatory in Arizona have observed an unusual Jupiter-like planet in orbit around a cool red dwarf star. This planet, designated TOI-3757 b, is located about 580 light-years from Earth in the constellation Auriga, the charioteer, and is the lowest density planet ever discovered around a red dwarf star. Researchers estimate that its average density is equivalent to that of a marshmallow. Red dwarf stars are the smallest and faintest members of the so-called main sequence stars - stars that convert hydrogen to helium at a uniform rate in their…
Record: Most severe gamma eruption observed to date
A cosmic explosion of gigantic proportions kept astronomers on tenterhooks in mid-October - the closest and possibly most energetic gamma-ray burst (GRB) ever observed. The GRB, designated GRB 221009A, occurred at a distance of about 2.4 billion light-years in the direction of the constellation Arrow. It was first detected on the morning of Oct. 9 by X-ray and gamma-ray space telescopes, including NASA's Fermi Gamma-ray Space Telescope, the Neil Gehrels Swift Observatory and the Wind spacecraft. As news of this discovery quickly spread, two teams of astronomers worked closely with Gemini South staff to obtain the earliest possible observations…
The ashes of the very first stars
The universe was just 100 million years old when the first stars already flared up. Very early on, dark matter amplified inhomogeneities in the structure of the universe in such a way that there were areas with a higher concentration of hydrogen. This clumped together, and as still happens today, a star was formed. With our sun these very first cosmic beacons, which are called "Population III" today, are hardly comparable. They must have consisted mainly of hydrogen and helium - already because there were no other elements at all in the early universe. This is how these stars should…
Conditions for life in the Enceladus ocean increasingly certain
Saturn's moon plays a special role in my books. Therefore, I am always very happy when there is news about possible life in the moon's ice ocean. Like the following. A team of scientists has apparently discovered new evidence for an important building block for life in the subsurface ocean of Saturn's moon Enceladus. Their model calculations suggest that Enceladus' ocean should be relatively rich in dissolved phosphorus, an essential ingredient for life. "Enceladus is one of the most important targets in humanity's search for life in our solar system," said Dr. Christopher Glein of Southwest Research Institute, a…
Gas bubble chases around core of Milky Way
Astronomers have discovered a hot gas bubble rotating clockwise around the black hole Sagittarius A* - the core of our Galaxy. However, this bubble has not been found directly, but via an accompanying phenomenon: flares in the X-ray range, which have been detected again and again, starting from the black hole Sgr A*. Since nothing can leave the black hole itself, a phenomenon in the immediate vicinity must be responsible - the gas bubble. (more…)
What do black holes have to do with the Big Bang?
A few milliseconds after the Big Bang, there was apparent chaos in the universe. While particles merged and broke apart again, incredibly strong pressure waves ran through the early cosmos. They pressed the particles so tightly against each other that black holes were formed, today called primordial black holes by astrophysicists. What impact did these black holes have on the formation of the first stars, about a hundred million years later? The Standard Model assumes that black holes at that time favored the formation of halo-like structures through their gravitational pull as condensation nuclei, similar to how clouds are formed…