ALMA: Liberal Sprinkling of Salt Discovered around a Young Star

Find out the latest thinking about our universe.
User avatar
bystander
Apathetic Retiree
Posts: 18251
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

ALMA: Liberal Sprinkling of Salt Discovered around a Young Star

Post by bystander » Sat Feb 09, 2019 2:56 am

Liberal Sprinkling of Salt Discovered around a Young Star
ALMA | NRAO | NAOJ | ESO | 2019 Feb 08

New ALMA observations show there is ordinary table salt in a not-so-ordinary location: 1,500 light-years from Earth in the disk surrounding a massive young star. Though salts have been found in the atmospheres of old, dying stars, this is the first time they have been seen around young stars in stellar nurseries. The detection of this salt-encrusted disk may help astronomers study the chemistry of star formation as well as identify other similar protostars hidden inside dense cocoons of dust and gas.

Salty Protostar ~ New ALMA observations show there is ordinary table salt in a not-so-
ordinary location: 1,500 light-years from Earth in the disk surrounding a massive young
star. Credit: ALMA (NRAO/ESO/NAOJ); NRAO/AUI/NSF; Gemini Observatory/AURA

A team of astronomers and chemists using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, a massive, young star in a dusty cloud behind the Orion Nebula. ...

To detect molecules in space, astronomers use radio telescopes to search for their chemical signatures – telltale spikes in the spread-out spectra of radio and millimeter-wavelength light. Atoms and molecules emit these signals in several ways, depending on the temperature of their environments.

The new ALMA observations contain a bristling array of spectral signatures – or transitions, as astronomers refer to them – of the same molecules. To create such strong and varied molecular fingerprints, the temperature differences where the molecules reside must be extreme, ranging anywhere from 100 kelvin to 4,000 kelvin (about -175 Celsius to 3700 Celsius). An in-depth study of these spectral spikes could provide insights about how the star is heating the disk, which would also be a useful measure of the luminosity of the star. ...

The researchers speculate that these salts come from dust grains that collided and spilled their contents into the surrounding disk. Their observations confirm that the salty regions trace the location of the circumstellar disk. ...

Orion Source I's Disk Is Salty ~ Adam Ginsburg et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

User avatar
Ann
4725 Å
Posts: 9455
Joined: Sat May 29, 2010 5:33 am

Re: ALMA: Liberal Sprinkling of Salt Discovered around a Young Star

Post by Ann » Sat Feb 09, 2019 5:57 am

Orion Nebula in infrared with hidden massive star (in orange cloud).
http://www.eso.org/gallery/v/ESOPIA/Neb ... 1.jpg.html
ALMA wrote:

A team of astronomers and chemists using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, a massive, young star in a dusty cloud behind the Orion Nebula.
The picture at left is from 2010 and was a bit of a sensation when it was first published. Note the Trapezium stars at center and the orange blob to the upper right of them. I assume that the star being discussed in ALMA's text is the one causing the orange flares in the infrared picture at left.

Some years ago, maybe in 2015 or so, I managed to find some more info about the hidden massive star. Now I can't find the info at all, but the way I remember it, the star was a B-type star, probably containing some (let me guess) 6-8 solar masses. That is massive, but not spectacular.

Anyway, can we be sure that low-mass stars create the same "rest products" (such as salt) during their formation as high-mass stars do?

Ann
Color Commentator

BDanielMayfield
Don't bring me down
Posts: 1947
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: ALMA: Liberal Sprinkling of Salt Discovered around a Young Star

Post by BDanielMayfield » Sat Feb 09, 2019 12:53 pm

Ann wrote:
Sat Feb 09, 2019 5:57 am
Anyway, can we be sure that low-mass stars create the same "rest products" (such as salt) during their formation as high-mass stars do?
It would be logical that they would Ann, at least in part. I looked it up, and in our solar system Na and Cl are the 11th and 17th most abundant elements. Of course each of this pair will also be binding up with other elements too, but they like each other especially well, as Na has one outer shell electron while Cl needs one to fill it's outer shell.

P.S. Your referring to a low-mass protostar accretion disk I presume?
"Happy are the peaceable ... "

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15888
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: ALMA: Liberal Sprinkling of Salt Discovered around a Young Star

Post by neufer » Sat Feb 09, 2019 1:03 pm


Art Neuendorffer

keflavich
Asternaut
Posts: 1
Joined: Mon Nov 10, 2008 1:38 am

Re: ALMA: Liberal Sprinkling of Salt Discovered around a Young Star

Post by keflavich » Thu Feb 14, 2019 8:51 pm

It's almost certain that salts exist around low-mass stars too, but it's possible they are never released into the gas phase around those stars because they don't heat their disks quite enough. In this object, Source I, which is a ~15 solar mass star, the region that got hot enough to release NaCl and KCl into the gas phase is 30-60 AU from the star. Around a more typical star like our sun, the equivalently warm area would be closer in, at a distance less than about 5 AU from the star. I think it is well worth looking at some low-mass stars with disks to see if they have gas-phase salts, but so far, no one has seen them if they're there.