Featured Research

from universities, journals, and other organizations

Astronomers find ice and possibly methane on Snow White, a distant dwarf planet

Date:
August 22, 2011
Source:
California Institute of Technology
Summary:
Astronomers have discovered that the dwarf planet 2007 OR10 -- nicknamed Snow White -- is an icy world, with about half its surface covered in water ice that once flowed from ancient, slush-spewing volcanoes. The new findings also suggest that the red-tinged dwarf planet may be covered in a thin layer of methane, the remnants of an atmosphere that's slowly being lost into space.

An artist's conception of 2007 OR10, nicknamed Snow White. Astronomers suspect that its rosy color is due to the presence of irradiated methane.
Credit: NASA

Astronomers at the California Institute of Technology (Caltech) have discovered that the dwarf planet 2007 OR10 -- nicknamed Snow White -- is an icy world, with about half its surface covered in water ice that once flowed from ancient, slush-spewing volcanoes. The new findings also suggest that the red-tinged dwarf planet may be covered in a thin layer of methane, the remnants of an atmosphere that's slowly being lost into space.

"You get to see this nice picture of what once was an active little world with water volcanoes and an atmosphere, and it's now just frozen, dead, with an atmosphere that's slowly slipping away," says Mike Brown, the Richard and Barbara Rosenberg Professor and professor of planetary astronomy, who is the lead author on a paper to be published in the Astrophysical Journal Letters describing the findings. The paper is now in press.

Snow White -- which was discovered in 2007 as part of the PhD thesis of Brown's former graduate student Meg Schwamb -- orbits the sun at the edge of the solar system and is about half the size of Pluto, making it the fifth largest dwarf planet. At the time, Brown had guessed incorrectly that it was an icy body that had broken off from another dwarf planet named Haumea; he nicknamed it Snow White for its presumed white color.

Soon, however, follow-up observations revealed that Snow White is actually one of the reddest objects in the solar system. A few other dwarf planets at the edge of the solar system are also red. These distant dwarf planets are themselves part of a larger group of icy bodies called Kuiper Belt Objects (KBOs). As far as the researchers could tell, Snow White, though relatively large, was unremarkable -- just one out of more than 400 potential dwarf planets that are among hundreds of thousands of KBOs.

"With all of the dwarf planets that are this big, there's something interesting about them -- they always tell us something," Brown says. "This one frustrated us for years because we didn't know what it was telling us." At that time, the Near Infrared Camera (NIRC) at the Keck Observatory -- which Caltech professor of physics Tom Soifer and chief instrument scientist Keith Matthews helped design in the 1990s -- was the best instrument astronomers had to study KBOs, according to Brown. But NIRC had just been retired, so no one could observe 2007 OR10 in detail. "It kind of languished," he says.

Meanwhile, Adam Burgasser, a former graduate student of Brown's and now a professor at UC San Diego, was helping to design a new instrument called the Folded-port Infrared Echellette (FIRE). Last fall, Brown, Burgasser, and postdoctoral scholar Wesley Fraser used this instrument with the 6.5-meter Magellan Baade Telescope in Chile to take a closer look at 2007 OR10.

As expected, Snow White was red. But to their surprise, the spectrum revealed that the surface was covered in water ice. "That was a big shock," Brown says. "Water ice is not red." Although ice is common in the outer solar system, it's almost always white.

There is, however, one other dwarf planet that's both red and covered with water ice: Quaoar, which Brown helped discover in 2002. Slightly smaller than Snow White, Quaoar is still big enough to have had an atmosphere and a surface covered with volcanoes that spewed an icy slush, which then froze solid as it flowed over the surface.

But because Quaoar isn't as big as dwarf planets like Pluto or Eris, it could not hold onto volatile compounds like methane, carbon monoxide, or nitrogen as long. A couple of billion years after Quaoar formed, it began to lose its atmosphere to space; now, all that remains is some methane. Over time, exposure to the radiation from space turned that methane -- which consists of a carbon atom bonded to four hydrogen atoms -- into long hydrocarbon chains, which look red. Like the frost that covers a lawn on a cold morning, the irradiated methane sits on Quaoar's icy surface, giving it a rosy hue.

The spectrum of 2007 OR10 looks similar to Quaoar's, suggesting that what happened on Quaoar also happened on 2007 OR10. "That combination -- red and water -- says to me, 'methane,'" Brown explains. "We're basically looking at the last gasp of Snow White. For four and a half billion years, Snow White has been sitting out there, slowly losing its atmosphere, and now there's just a little bit left."

Although Snow White's spectrum clearly shows the presence of water ice, Brown says, the evidence for methane is not yet definitive. To find out, the astronomers will have to use a big telescope like the one at the Keck Observatory. If it turns out that Snow White does indeed have methane, it will join Quaoar as one of only two dwarf planets that straddle the border between the handful of objects large enough to hold onto volatile compounds, and the smaller bodies that make up the vast majority of KBOs.

Another task, Brown says, is to give the dwarf planet an official name, since "Snow White" was just a nickname he and his colleagues used. Besides, the moniker no longer makes sense for describing this very red object. Before the discovery of water ice and the possibility of methane, "2007 OR10" might have sufficed for the astronomy community, since it didn't seem noteworthy enough to warrant an official name. "We didn't know Snow White was interesting," Brown says. "Now we know it's worth studying."


Story Source:

The above story is based on materials provided by California Institute of Technology. The original article was written by Marcus Woo. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. E. Brown, A. J. Burgasser, W. C. Fraser. The surface composition of large Kuiper Belt Object 2007 OR10. Astrophysical Journal Letters, 2011; DOI: 10.1088/2041-8205/738/2/L26

Cite This Page:

California Institute of Technology. "Astronomers find ice and possibly methane on Snow White, a distant dwarf planet." ScienceDaily. ScienceDaily, 22 August 2011. <www.sciencedaily.com/releases/2011/08/110822124955.htm>.
California Institute of Technology. (2011, August 22). Astronomers find ice and possibly methane on Snow White, a distant dwarf planet. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2011/08/110822124955.htm
California Institute of Technology. "Astronomers find ice and possibly methane on Snow White, a distant dwarf planet." ScienceDaily. www.sciencedaily.com/releases/2011/08/110822124955.htm (accessed October 1, 2014).

Share This



More Space & Time News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Astronomers Spot Largest, Brightest Solar Flare Ever

Astronomers Spot Largest, Brightest Solar Flare Ever

Newsy (Oct. 1, 2014) — The initial blast from the record-setting explosion would have appeared more than 10,000 times more powerful than any flare ever recorded. Video provided by Newsy
Powered by NewsLook.com
French Apple Fans Discover the Apple Watch

French Apple Fans Discover the Apple Watch

AFP (Sep. 30, 2014) — Apple fans in France discover the latest toy, the Apple Watch. The watch comes in two sizes and an array of interchangeable, fashionable wrist straps. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
The Water You Drink Might Be Older Than The Sun

The Water You Drink Might Be Older Than The Sun

Newsy (Sep. 27, 2014) — Researchers at the University of Michigan simulated the birth of planets and our sun to determine whether water in the solar system predates the sun. Video provided by Newsy
Powered by NewsLook.com
First Woman Cosmonaut in 17 Years Blasts Off for ISS

First Woman Cosmonaut in 17 Years Blasts Off for ISS

AFP (Sep. 26, 2014) — A Russian Soyuz spacecraft carrying an American astronaut and two Russian cosmonauts, including the first woman cosmonaut in 17 years, blasted off on schedule Friday. Duration: 00:35 Video provided by AFP
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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