A Chalmers-led group of astronomers has for the primary time noticed particulars on the floor of an getting old star with the identical mbad because the Sun. Alma:s pictures present that the star is a huge, its diameter twice the dimensions of Earth’s orbit across the Sun, but additionally that the star’s environment is affected by highly effective, sudden shock waves. The badysis is revealed in Nature Astronomy on 30 October 2017.
A group of astronomers led by Wouter Vlemmings, Chalmers University of Technology, have used the telescope ALMA to make the sharpest observations but of a star with the identical beginning mbad because the Sun. The new pictures present for the primary time particulars on the floor of the purple big W Hydrae, 320 mild years distant within the constellation of Hydra, the Water Snake.
W Hydrae is an instance of an AGB (asymptotic big department) star. Such stars are cool, brilliant, previous and lose mbad by way of stellar winds. The identify derives from their place on the well-known Hertzsprung-Russell diagram, which clbadifies stars in accordance with their brightness and temperature.
“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. 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,” says Wouter Vlemmings.
Stars just like the Sun evolve over timescales of many billion years. When they attain previous age, they puff up and turn into greater, cooler and extra susceptible to lose mbad within the type of stellar winds. Stars manufacture essential parts like carbon and nitrogen. When they attain the purple big stage, these parts are launched into area, prepared for use in subsequent generations of recent stars.
Alma:s pictures present the clearest view but of the floor of a purple big with an identical mbad to the Sun. Earlier sharp pictures have proven particulars on rather more large, purple supergiant stars like Betelgeuse and Antares.
The observations have additionally stunned the scientists. The presence of an unexpectedly compact and brilliant spot offers proof that the star has surprisingly scorching fuel in a layer above the star’s floor: a 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,” says Theo Khouri, astronomer at Chalmers and member of the group.
An various chance is a minimum of as stunning: that the star was present process a large flare when the observations had been made.
The scientists at the moment are finishing up new observations, each with Alma and different devices, to higher perceive W Hydrae’s stunning environment. Observations like these with Alma’s highest-resolution configuration are difficult, but additionally rewarding, explains group member Elvire De Beck, additionally astronomer at Chalmers.
“It’s humbling to look at our image of W Hydrae and see its size compared to the orbit of the Earth. 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,” added De Beck.
Research Report: “The shock-heated atmosphere of an asymptotic giant branch star resolved by ALMA”
Forest of molecular alerts in star forming galaxy
Tokyo, Japan (SPX) Nov 07, 2017
Ryo Ando, a graduate scholar of the University of Tokyo, and his colleagues noticed the galaxy NGC 253 and for the primary time, they resolved the areas of star formation on this galaxy right down to the size of a molecular cloud, which is a star formation web site with a dimension of about 30 light-years. As a outcome, they recognized eight large, dusty clouds aligned alongside the middle of the galaxy.
… learn extra
Chalmers University of Technology
Stellar Chemistry, The Universe And All Within It
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