The death throes of a nearby fading star

The death throes of a nearby fading star
The death throes of a nearby fading star

NASA has discovered the first dying star in the vicinity of our solar system. It will take only a few hundred to thousands of years for a dying Sun as a star, many billions of years to transform into dazzling, glowing clouds called planetary nebulae. This relative blinking is a fairly long lifespan. And this means that for stars like the Sun, the last minutes are a decisive stage.

Astronomers, led by NASA's Jet Propulsion Dr. Ravendra Sahai at Pasadena Laboratories, California, have caught one of these dying stars at the scene of a crime. This nearby star, called V Hydrae, was discovered through the Hubble Space Telescope.

Although previous studies have shown the role of jet streams in the formation of planetary nebulae, the new data represent the first that these jets have been directly detected.

“The discovery of a recently begun outflow jet is likely to have a significant impact on our understanding of this short-lived stage in stellar evolution and open a window to the ultimate fate of our Sun,” Sahai said.

Low-mass stars like the Sun usually survive for about ten billion years before their hydrogen fuel starts to dry up and they begin to die. Over the next ten to one hundred thousand years, stars slowly lose almost half of their mass, which is carried by spherical winds. Further - in a still poorly understood stage lasting only 100 to 1000 years - the stars turn into a stunning array of geometric shapes of glowing clouds called planetary nebulae.

How long these amazing "star clouds" are formed is still unclear, although Sakhai, in a number of previous works, put forward a new hypothesis. Based on the results of the image taken from the Hubble Space Telescope: images of young planetary nebulae, he proposed that both sides are bipolar, high-speed jet outflow is the main means of forming these objects. The latest research will allow Sakhai and his colleagues to test this hypothesis.

V Hydrae

“Now, in the case of V Hydrae, we can observe the evolution of the outflow jet in real time,” said Sahai, who, along with his colleagues, will study the stars from the Hubble Space Telescope for another three years.

New data also shows what may be causing the jet outflow. Past models of dying stars predict that accretion disks - the swirling rings of matter surrounding a star - could cause jet outflows. V Hydrae data confirm the presence of an accretion disk of surrounding matter, as well as a companion - a companion plying around the star. It will probably be another star, or even a giant planet. Although she herself and her companion, unlike the accretion disk, look too dim, so they are almost indistinguishable. The authors also found evidence of large, dense disks in V Hydrae that could have allowed an accretion disk to form around the companion.

Space Telescope Imaging The spectrograph is operated by NASA's Goddard Space Flight Center in Greenbelt, Maryland. The Hubble Space Telescope is an international collaboration between NASA and the European Space Agency. California Institute of Technology, Pasadena operates JPL for NASA.

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