Featured Research

from universities, journals, and other organizations

Solar Wind Tans Young Asteroids

Date:
April 27, 2009
Source:
ESO
Summary:
A new study reveals that asteroid surfaces age and redden much faster than previously thought -- in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids. This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid.

Artist's impression of how the solar wind makes young asteroids look old. After undergoing a catastrophic collision, the colour of an asteroid gets modified rapidly by the solar wind so that it resembles the mean colour of extremely old asteroids. After the first million years, the surface "tans" much more slowly. At that stage, the colour depends more on composition than on age.
Credit: ESO

A new study published in Nature this week reveals that asteroid surfaces age and redden much faster than previously thought — in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids.

This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid.

“Asteroids seem to get a ‘sun tan’ very quickly,” says lead author Pierre Vernazza. “But not, as for people, from an overdose of the Sun’s ultraviolet radiation, but from the effects of its powerful wind.”

It has long been known that asteroid surfaces alter in appearance with time — the observed asteroids are much redder than the interior of meteorites found on Earth [1] — but the actual processes of this “space weathering” and the timescales involved were controversial.

Thanks to observations of different families of asteroids [2] using ESO’s New Technology Telescope at La Silla and the Very Large Telescope at Paranal, as well as telescopes in Spain and Hawaii, Vernazza’s team have now solved the puzzle.

When two asteroids collide, they create a family of fragments with “fresh” surfaces. The astronomers found that these newly exposed surfaces are quickly altered and change colour in less than a million years — a very short time compared to the age of the Solar System.

“The charged, fast moving particles in the solar wind damage the asteroid’s surface at an amazing rate [3]”, says Vernazza. Unlike human skin, which is damaged and aged by repeated overexposure to sunlight, it is, perhaps rather surprisingly, the first moments of exposure (on the timescale considered) — the first million years — that causes most of the aging in asteroids.

By studying different families of asteroids, the team has also shown that an asteroid’s surface composition is an important factor in how red its surface can become. After the first million years, the surface “tans” much more slowly. At that stage, the colour depends more on composition than on age. Moreover, the observations reveal that collisions cannot be the main mechanism behind the high proportion of “fresh” surfaces seen among near-Earth asteroids. Instead, these “fresh-looking” surfaces may be the results of planetary encounters, where the tug of a planet has “shaken” the asteroid, exposing unaltered material.

Thanks to these results, astronomers will now be able to understand better how the surface of an asteroid — which often is the only thing we can observe — reflects its history.

Notes

[1] Meteorites are small fragments of asteroids that fall on Earth. While a meteorite enters the Earth's atmosphere its surface can melt and be partially charred by the intense heat. Nevertheless, the meteorite interior remains unaffected, and can be studied in a laboratory, providing a wealth of information on the nature and composition of asteroids.

[2] An asteroid family is a group of asteroids that are on similar orbits around the Sun. The members of a given family are believed to be the fragments of a larger asteroid that was destroyed during a collision.

[3] The surface of an asteroid is affected by the highly energetic particles forming the solar wind. These particles partially destroy the molecules and crystals on the surface, re-arranging them in other combinations. Over time, these changes give formation of a thin crust or irradiated material with distinct colours and properties.


Story Source:

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


Journal Reference:

  1. Vernazza et al. Solar wind as the origin of rapid reddening of asteroid surfaces. Nature, 2009; 458 (7241): 993 DOI: 10.1038/nature07956

Cite This Page:

ESO. "Solar Wind Tans Young Asteroids." ScienceDaily. ScienceDaily, 27 April 2009. <www.sciencedaily.com/releases/2009/04/090422132918.htm>.
ESO. (2009, April 27). Solar Wind Tans Young Asteroids. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2009/04/090422132918.htm
ESO. "Solar Wind Tans Young Asteroids." ScienceDaily. www.sciencedaily.com/releases/2009/04/090422132918.htm (accessed July 30, 2014).

Share This




More Space & Time News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Supply Ship Takes Off for International Space Station

Supply Ship Takes Off for International Space Station

AFP (July 30, 2014) The European Space Agency's fifth Automated Transfer Vehicle (ATV-5) is takes off to the International Space Station on an Ariane 5 rocket from French Guiana. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Raw: Rocket Launches Into Space With Cargo Ship

Raw: Rocket Launches Into Space With Cargo Ship

AP (July 30, 2014) Arianespace launched a rocket Tuesday from French Guiana carrying a robotic cargo ship to deliver provisions to the International Space Station. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
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:
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