The dying star unleashes mysterious circles

Astronomers have discovered that the red giant star V Hydrae is releasing strange smoke-like rings before exploding.

As low- to mid-mass stars run out of hydrogen fuel in their cores, the external pressure becomes unbalanced with the gravity inside, causing them to collapse. Once there, the plasma shell surrounding the core becomes hot enough to initiate hydrogen fusion, producing heat that dramatically expands the outer layers of the object, turning it into a red giant star.

Simulation of the star V Hydrae launching matter into space.

V Hydrae is one such object. It is located about 1,300 light-years from Earth and is entering its final stages of evolution before collapsing into a white dwarf. During this phase, the stars suck up matter from their cores and spew out into the surrounding space.

In a new study published in the Astrophysical Journal, astronomers say that V Hydrae is ejecting six rings of hazy smoke, along with a giant hourglass-shaped structure. The discovery is based on observations from the Hubble space telescope and the ALMA radio telescope system in the Atacama Desert in Chile.

According to study lead author Raghvendra Sahai from NASA's Jet Propulsion Laboratory, the hourglass-shaped structure is made up of two clouds of matter and jet beams erupting from the star's poles at high speeds. up to 240 km/s. It is perpendicular to the plane containing the mysterious smoke circles.

Hourglass clouds are not entirely new discoveries. Astronomers have observed a similar phenomenon in the Southern Crab Nebula 6,849 light-years from Earth. At the center of this nebula is a binary pair, consisting of a white dwarf and a red giant.

In addition to the mysterious smoke rings and hourglass cloud structures, V Hydrae also emits explosions of superheated gas, or plasma, about every 8.5 years. The team suspects these strange behaviors may be related to a companion star, but its existence has yet to be confirmed.

"V Hydrae's activity is interesting, because our Sun may one day have a similar fate," said co-author Mark Morris at the University of California in the US. Tracking the behavior of such objects will help astronomers better understand what happens in the final stages of stellar evolution.