ALMA’s image of a red giant star reveals glimpse into sun’s future

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  • The star, called W Hydrae, sits 320 light years away and is same mass as the sun
  • Observations revealed the atmosphere is experiencing powerful shock waves
  • The researchers say the observations show a glimpse at the future of the sun 

Cheyenne Macdonald For Dailymail.com

Scientists have observed the surface of an aging ‘red giant’ star 320 light years away, revealing new insight on what the future might look like for the star at the heart of our own solar system.

The star, known as W Hydrae, sits in the constellation Hydra and is the same mass as the sun.

Researchers observing the star with the Atacama Large Millimetre/Submillimetre Array (ALMA) have discovered powerful, unexpected shock waves in its atmosphere, with temperatures far surpassing what the models predict.

Scientists have observed the surface of an aging ‘red giant’ star 320 light years away, revealing new insight on what the future might look like for the star at the heart of our own solar system. The dotted ring maps the size of Earth's orbit around the sun, for comparison

Scientists have observed the surface of an aging ‘red giant’ star 320 light years away, revealing new insight on what the future might look like for the star at the heart of our own solar system. The dotted ring maps the size of Earth's orbit around the sun, for comparison

Scientists have observed the surface of an aging ‘red giant’ star 320 light years away, revealing new insight on what the future might look like for the star at the heart of our own solar system. The dotted ring maps the size of Earth’s orbit around the sun, for comparison

MISSING RED GIANTS 

Recent simulations led by Georgia Tech astrophysicsts suggest ancient red giant stars may have been subjected to repeated collisions with a massive accretion disk, stripping away much of their mass, and causing them to ‘disappear’ from the Milky Way. 

Red giant stars may each have orbited through the disk dozens of times, some taking days or even weeks to complete the crossing, losing mass each time.

As these stars collided with the disk, they also likely reduced kinetic energy by 20 to 30%, the researchers say.

This would have shrunk their orbits and drawn them close to the Milky Way’s black hole.

And, it could have caused them to spin more rapidly.

The simulations support the hypothesis that red giants are still there, but they are too dim to be seen.

‘For us, it’s important to study not just what red giants look like, but how they change and how they seed the galaxy with the elements that are the ingredients of life,’ said Wouter Vlemmings, of Chalmers University of Technology.

‘Using the antennas of ALMA in their highest-resolution configuration, we can now make the most detailed observations ever of these cool and exciting stars.’

The researchers were able to capture the sharpest images yet, revealing details on the surface of the red giant for the first time.

W Hydrae is what’s known as an AGB (asymptotic giant branch) star, being cool and bright.

These stars also lose mass through stellar winds.

This particular star is the same mass as the sun, and the new observations reveal ‘surprising’ processes taking place at the surface.

W Hydrae is what’s known as an AGB (asymptotic giant branch) star, being cool and bright. These stars also lose mass through stellar winds. The image shows the sky around W Hydrae, in visible light

W Hydrae is what’s known as an AGB (asymptotic giant branch) star, being cool and bright. These stars also lose mass through stellar winds. The image shows the sky around W Hydrae, in visible light

W Hydrae is what’s known as an AGB (asymptotic giant branch) star, being cool and bright. These stars also lose mass through stellar winds. The image shows the sky around W Hydrae, in visible light

According to the team, there is a hot gas layer above the surface, in a region known as the chromosphere.

‘Our measurements of the bright spot suggest there are powerful shock waves in the star’s atmosphere that reach higher temperatures than are predicted by current theoretical models for AGB stars,’ said Theor Khouri, an astronomer at Chalmers.

The researchers say the phenomenon could also be the result of a giant flare taking place at the time of the observations.

The researchers were able to capture the sharpest images yet, revealing details on the surface of the red giant for the first time.

The researchers were able to capture the sharpest images yet, revealing details on the surface of the red giant for the first time.

The researchers were able to capture the sharpest images yet, revealing details on the surface of the red giant for the first time.

But, this explanation would also be considered surprising, they say.

With additional observations using ALMA and other instruments, the experts hope to better understand what’s going on at W Hydrae.

And, doing so could shed light on the future of the sun.

‘It’s humbling to look at our image of W Hydrae and see its size compared to the orbit of the Earth,’ said astronomer Elvire De Beck.

‘We are born from material created in stars like this, so for us it’s exciting to have the challenge of understanding something which so tells us both about our origins and our future.’

The sharpest image yet of a red giant star: 320 light years from Earth, the star W Hydrae is a few billion years further on than the Sun in its life. The dotted rings show the size of the orbits of the Earth (in blue) and other planets around the Sun for comparison. The system is seen at an angle. Alma is sensitive to submillimetre wavelengths; this image is taken at around 0,9 mm.

The sharpest image yet of a red giant star: 320 light years from Earth, the star W Hydrae is a few billion years further on than the Sun in its life. The dotted rings show the size of the orbits of the Earth (in blue) and other planets around the Sun for comparison. The system is seen at an angle. Alma is sensitive to submillimetre wavelengths; this image is taken at around 0,9 mm.

The sharpest image yet of a red giant star: 320 light years from Earth, the star W Hydrae is a few billion years further on than the Sun in its life. The dotted rings show the size of the orbits of the Earth (in blue) and other planets around the Sun for comparison. The system is seen at an angle. Alma is sensitive to submillimetre wavelengths; this image is taken at around 0,9 mm.