Category Astronomy/Space

Could dying stars hold the secret to looking younger? New evidence suggests that white dwarfs could continue to burn hydrogen in the final stages of their lives, causing them to appear more youthful than they actually are. This discovery could have consequences for how astronomers measure the ages of star clusters.

The prevalent view of white dwarfs as inert, slowly cooling stars has been challenged by observations from the NASA/ESA Hubble Space Telescope. An international group of astronomers have discovered the first evidence that white dwarfs can slow down their rate of ageing by burning hydrogen on their surface.

“We have found the first observational evidence that white dwarfs can still undergo stable thermonuclear activity,” explained Jianxing Chen of the Alma Mater Studio...

As their name suggests, ultradiffuse galaxies, or UDGs, are dwarf galaxies whose stars are spread out over a vast region, resulting in extremely low surface brightness, making them very difficult to detect. Several questions about UDGs remain unanswered: How did these dwarfs end up so extended? Are their dark matter halos – the halos of invisible matter surrounding the galaxies – special?

Now an international team of astronomers, co-led by Laura Sales, an astronomer at the University of California, Riverside, reports in Nature Astronomythat it has used sophisticated simulations to detect a few “quenched” UDGs in low-...

Astronomers have found dramatic evidence that a black hole or neutron star spiraled its way into the core of a companion star and caused that companion to explode as a supernova. The astronomers were tipped off by data from the Very Large Array Sky Survey (VLASS), a multi-year project using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA).

“Theorists had predicted that this could happen, but this is the first time we’ve actually seen such an event,” said Dillon Dong, a graduate student at Caltech and lead author on a paper reporting the discovery in the journal Science.

The first clue came when the scientists examined images from VLASS, which began observations in 2017, and found an object brightly emitting radio waves but ...

In the early solar system, terrestrial planets like Mercury, Venus, Earth and Mars are thought to have formed from planetesimals, small early planets. These early planets grew over time, through collisions and mergers, to make them the size they are today.

The material released from these violent collisions is commonly thought to have escaped and orbited around the sun, bombarding the growing planets and altering the composition of the asteroid belt...