ESO: Aging Star Blows Off Smoky Bubble

[bystander]

Aging Star Blows Off Smoky Bubble
ESO Photo Release | ALMA | 2017 Sep 20

[img3="This ALMA image reveals much finer structure in the U Antliae shell than has previously been possible. Credit: ALMA (ESO/NAOJ/NRAO)/F. Kerschbaum"]https://cdn.eso.org/images/screen/eso1730a.jpg[/img3][hr][/hr]

Astronomers have used ALMA to capture a strikingly beautiful view of a delicate bubble of expelled material around the exotic red star U Antliae. These observations will help astronomers to better understand how stars evolve during the later stages of their life-cycles.

In the faint southern constellation of Antlia (The Air Pump) the careful observer with binoculars will spot a very red star, which varies slightly in brightness from week to week. This very unusual star is called U Antliae and new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) are revealing a remarkably thin spherical shell around it.

U Antliae [1] is a carbon star, an evolved, cool and luminous star of the asymptotic giant branch type. Around 2700 years ago, U Antliae went through a short period of rapid mass loss. During this period of only a few hundred years, the material making up the shell seen in the new ALMA data was ejected at high speed. Examination of this shell in further detail also shows some evidence of thin, wispy gas clouds known as filamentary substructures.

This spectacular view was only made possible by the unique ability to create sharp images at multiple wavelengths that is provided by the ALMA radio telescope, located on the Chajnantor Plateau in Chile’s Atacama Desert. ALMA can see much finer structure in the U Antliae shell than has previously been possible. ...

Rings and Filaments: The Remarkable Detached CO Shell of U Antliae - F. Kerschbaum et al

• Astronomy & Astrophysics 605:A116 (Sep 2017) DOI: 10.1051/0004-6361/201730665
  arXiv.org > astro-ph > arXiv:1708.02915 > 09 Aug 2017

[geckzilla]

ALMA press releases are quickly becoming my favorite.

[Ann]

It's indeed an interesting picture.

The B-V of U Antlia is 3.015 ± 0.014, so the star is quite red, though not record red, not like T Lyrae (5.460 ± 0.510), for example.

The parallax of U Antlia is 3.73 ± 0.54 milliarcseconds, corresponding to a distance of 268 ± 39 parsecs, or 870 ± 130 light-years. So the star is not terrifically distant.

Coupled with the star's apparent V mag of 5.853 ± 0.003, its true V luminosity is 380 ± 110 solar. But since the star is so red and infrared, its bolometric (total) luminosity must be a lot more.

Ann

[BDanielMayfield]

Thanks for sharing this Ann. Other fun facts about this star are its mass and radius. Mass wise it is very Sun-like at only 1.04 times solar, but it is a very giant Red Giant with a radius 350 times solar! The Sun would reach the current Earth orbit radius if or when it swells to 215 times solar, so U Antlia is big enough to have swallowed any planets clear out to Mars-like orbits.

Bruce

P.S. to nuefer: We can be sure that there are no more apocalypse deniers left in the U Antlia system.

[neufer]

Click to play embedded YouTube video.

[b][color=#0000FF][size=150]Johann Bode's depiction of Antlia as a double-cylinder air pump[/size][/color][/b]

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