Featured Research

from universities, journals, and other organizations

Astronomers discover sandstorms in space

Date:
April 11, 2012
Source:
Manchester University
Summary:
Astronomers believe they have found the answer to the mystery of a powerful ‘superwind’ which causes the death of stars.

An artist's impression of the red giant.
Credit: Image courtesy of Manchester University

Astronomers at The University of Manchester believe they have found the answer to the mystery of a powerful 'superwind' which causes the death of stars.

Writing in Nature, the team of researchers used new techniques which allowed them to look into the atmospheres of distant, dying stars.

The team, lead by Barnaby Norris from the University of Sydney in Australia, includes scientists from the Universities of Manchester, Paris-Diderot, Oxford and Macquarie University, New South Wales. They used the Very Large Telescope in Chile, operated by the European Southern Observatory.

At the resolution used by the scientists, one could, from the UK, distinguish the two headlights on a car in Australia. This extreme resolution made it possible to resolve the red giant stars, and to see winds of gas and dust coming off the star.

Stars like the Sun end their lives with a 'superwind', 100 million times stronger than the solar wind. This wind occurs over a period of 10,000 years, and removes as much as half the mass of the star. At the end, only a dying and fading remnant of the star will be left. The Sun will begin to throw out these gases in around five billion years.

The cause of this superwind has remained a mystery. Scientists have assumed that they are driven by minute dust grains, which form in the atmosphere of the star and absorb its light. The star light pushes the dust grains (silicates) away from the star.

However, models have shown that this mechanism does not work well. The dust grains become too hot, and evaporate before they can be pushed out.

The scientists have now discovered that the grains grow to much larger sizes than had previously been thought. The team found sizes of almost a micrometer -- as small as dust, but huge for stellar winds.

Grains of this size behave like mirrors, and reflect starlight, rather than absorbing it. This leaves the grains cool, and the star light can push them out without destroying them. This may be the solution to the mystery of the superwind.

The large grains are driven out by the star light at speeds of 10 kilometres per second, or 20 thousand miles per hour -- the speed of a rocket. The effect is similar to a sandstorm. Compared to grains of sands, the silicates in the stellar winds are still tiny.

Professor Albert Zijlstra, from The University of Manchester's Jodrell Bank Observatory, said the breakthrough changes our view of these superwinds. For the first time, we begin to understand how the superwinds work, and how stars (including, in the distant future, our Sun) die.

He added: "The dust and sand in the superwind will survive the star, and later become part of the clouds in space from which new stars form. The sand grains at that time become the building blocks of planets. Our own Earth has formed from star dust. We are now a big step further in understanding this cycle of life and death."


Story Source:

The above story is based on materials provided by Manchester University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Barnaby R. M. Norris, Peter G. Tuthill, Michael J. Ireland, Sylvestre Lacour, Albert A. Zijlstra, Foteini Lykou, Thomas M. Evans, Paul Stewart, Timothy R. Bedding. A close halo of large transparent grains around extreme red giant stars. Nature, 2012; 484 (7393): 220 DOI: 10.1038/nature10935

Cite This Page:

Manchester University. "Astronomers discover sandstorms in space." ScienceDaily. ScienceDaily, 11 April 2012. <www.sciencedaily.com/releases/2012/04/120411161602.htm>.
Manchester University. (2012, April 11). Astronomers discover sandstorms in space. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2012/04/120411161602.htm
Manchester University. "Astronomers discover sandstorms in space." ScienceDaily. www.sciencedaily.com/releases/2012/04/120411161602.htm (accessed April 23, 2014).

Share This



More Space & Time News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Raw: Easter Morning Delivery for Space Station

Raw: Easter Morning Delivery for Space Station

AP (Apr. 20, 2014) Space station astronauts got a special Easter treat: a cargo ship full of supplies. The SpaceX company's cargo ship, Dragon, spent two days chasing the International Space Station following its launch from Cape Canaveral. (April 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


New Life for Controversial Stellar Wind Theory

Apr. 12, 2012 Astronomers have succeeded in identifying a specific kind of dust grain in the vicinity of cool giant stars. This means fresh impetus for a controversial theory about how stars ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins