Subscribe free to our newsletters via your
. 24/7 Space News .




SOLAR SCIENCE
STEREO, SOHO Spacecraft Catch Comet Diving Into Sun
by Robert Sanders
Berkeley CA (SPX) May 26, 2010


Hydrogen-alpha (ultraviolet) observations of the sun's edge from the Coronado instrument of the Mauna Loa Solar Observatory showing what the authors believe to be the comet approaching the solar limb. (Claire Raftery, Juan Carlos Martinez-Oliveros, Samuel Krucker/UC Berkeley)

Solar physicists at the University of California, Berkeley, have tracked a comet through the low solar atmosphere, deeper into the sun than ever before, before it presumably evaporated in the 100,000-degree heat.

Using instruments aboard NASA's twin STEREO spacecraft, four post-doctoral fellows at UC Berkeley's Space Sciences Laboratory were able to track the comet as it approached the sun and estimate an approximate time and place of impact.

STEREO (Solar TErrestrial RElations Observatory), launched in 2006, consists of identical spacecraft orbiting the sun, one ahead of Earth and one behind Earth, providing a stereo view of the sun.

The researchers then looked at data from the ground-based Mauna Loa Solar Observatory in Hawaii, and found images in the predicted spot of what appears to be a comet approaching the edge of the sun from behind the solar disk.

"We believe this is the first time a comet has been tracked in 3-D space this low down in the solar corona," said Claire Raftery, a post-doctoral fellow newly arrived at UC Berkeley from Dublin's Trinity College.

The team will present its data and images during a 5:30-6:30 p.m. poster session on Monday, May 24, at the Miami, Fla., meeting of the American Astronomical Society.

Sungrazing comets, composed of dust, rock and ice, are seldom tracked close to the sun because their brightness is overwhelmed by the solar disk. This comet apparently survived the heat of the corona and disappeared in the chromosphere, evaporating in the 100,000-degree (Kelvin) heat.

Raftery and her colleagues, Juan Carlos Martinez-Oliveros, Samuel Krucker and Pascal Saint-Hilaire, concluded that the comet was probably one of the Kreutz family of comets, a swarm of Trojan or Greek comets ejected from their orbit in 2004 by Jupiter, and that it made its first and only loop around the sun. The swarm probably resulted from the disintegration of a larger comet.

Martinez-Oliveros' attention was first drawn to the comet after seeing it mentioned in a summary of March 12, 2010, observations by STEREO and by SOHO, the Solar and Heliospheric Observatory. The comet's long, bright Using instruments aboard NASA's twin STEREO spacecraft, four post-doctoral fellows at UC Berkeley's Space Sciences Laboratory were able to track the comet as it approached the sun and estimate an approximate time and place of impact. STEREO (Solar TErrestrial RElations Observatory), launched in 2006, consists of identical spacecraft orbiting the sun, one ahead of Earth and one behind Earth, providing a stereo view of the sun.

The researchers then looked at data from the ground-based Mauna Loa Solar Observatory in Hawaii, and found images in the predicted spot of what appears to be a comet approaching the edge of the sun from behind the solar disk.

"We believe this is the first time a comet has been tracked in 3-D space this low down in the solar corona," said Claire Raftery, a post-doctoral fellow newly arrived at UC Berkeley from Dublin's Trinity College.

The team will present its data and images during a 5:30-6:30 p.m. poster session on Monday, May 24, at the Miami, Fla., meeting of the American Astronomical Society.

Sungrazing comets, composed of dust, rock and ice, are seldom tracked close to the sun because their brightness is overwhelmed by the solar disk. This comet apparently survived the heat of the corona and disappeared in the chromosphere, evaporating in the 100,000-degree (Kelvin) heat.

Raftery and her colleagues, Juan Carlos Martinez-Oliveros, Samuel Krucker and Pascal Saint-Hilaire, concluded that the comet was probably one of the Kreutz family of comets, a swarm of Trojan or Greek comets ejected from their orbit in 2004 by Jupiter, and that it made its first and only loop around the sun. The swarm probably resulted from the disintegration of a larger comet.

Martinez-Oliveros' attention was first drawn to the comet after seeing it mentioned in a summary of March 12, 2010, observations by STEREO and by SOHO, the Solar and Heliospheric Observatory. The comet's long, bright tail of dust and ions tagged it as a sungrazing comet seen often by solar astronomers and observatories such as STEREO.

Assuming it was a going to loop around the sun, the researchers decided to see whether the STEREO data were good enough to let them calculate its trajectory.

In fact, the data were good enough to chart the comet's approach for two days before impact.

With an estimate of the impact zone within a circle about 1,000 kilometers in diameter, they searched online data from the Mauna Loa Solar Observatory to determine if they could see the comet next to the sun's edge in the ultraviolet region of the spectrum.

They found a short track, lasting about six minutes, just a few thousand kilometers above the sun's surface in the million-degree corona and 100,000-degree chromosphere.

Based on the comet's relatively short tail, about 3 million kilometers in length, the researchers believe that the comet contained heavier elements that do not evaporate readily. This would also explain how it penetrated so deeply into the chromosphere, surviving the strong solar wind as well as the extreme temperatures, before evaporating.

For their study, the team used the two coronagraphs on STEREO A and B and multiple instruments on SOHO, "demonstrat(ing) the importance of multi-view observations of non solar phenomena," they wrote in their poster.

All members of the team study explosive events on the sun, such as coronal mass ejections, and the hot ionized plasmas that they throw into space. The researchers' detour into cometary physics was purely accidental, they said.

"It was supposed to be an exercise, but it took over our lives," Raftery said.

.


Related Links
UC Berkeley
Solar Science News at SpaceDaily






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








SOLAR SCIENCE
Spacecraft Reveals Small Solar Events Have Large Scale Effects
Washington DC (SPX) May 26, 2010
NASA's Solar Dynamics Observatory, or SDO, has allowed scientists for the first time to comprehensively view the dynamic nature of storms on the sun. Solar storms have been recognized as a cause of technological problems on Earth since the invention of the telegraph in the 19th century. The Atmospheric Imaging Assembly (AIA), one of three instruments aboard SDO, allowed scientists to disco ... read more


SOLAR SCIENCE
Caterpillar Participates In Inaugural Lunabotics Mining Competition

Loral Announces Milestone in NASA Ames Project

Einstein And Einstein A: A Study In Crater Morphology

NASA Invites Public To Take Virtual Walk On Moon

SOLAR SCIENCE
New INL Invention Could Aid Mars Probes' Search For Life

Phoenix Crushed By Frost

Opportunity Recharging Between Drives

Martian probe Phoenix is kaput: NASA

SOLAR SCIENCE
Indian Space Programmes Serve Societal Needs

NASA Fixes Bug On Voyager 2

Aerojet Validates Engine Design For Orion Crew Exploration Vehicle

Japan rocket blasts off with 'space yacht' and Venus probe

SOLAR SCIENCE
Seven More For Shenzhou

China Signs Up First Female Astronauts

China To Launch Second Lunar Probe This Year

China, Bolivia to build communications satellite

SOLAR SCIENCE
STS-132 Crew Completes Inspection And Prepare For Landing

Crews Opening Rassvet Hatches And Prepares For Spacewalk

Atlantis astronaut complete final spacewalk

Atlantis astronauts complete second spacewalk

SOLAR SCIENCE
Ariane 5 Makes History With The ASTRA 3B And COMSATBw-2 Mission

Ariane 5 Is Poised For Launch With ASTRA 3B And COMSATBw-2

H2A Launches Six Satellites

Sea Launch Files Plan Of Reorganization

SOLAR SCIENCE
Get It While it's Hot! Star Devours Planet

Exoplanetary System Offers Clues To Disturbed Past

Planet discovered lacking methane

'This Planet Tastes Funny,' According To Spitzer

SOLAR SCIENCE
Apple iPad to make international debut on Friday

New Video Of First US Weather Satellite

Northrop Grumman Tests First Airborne Ka-Band Satellite Terminal

Retail giant Wal-Mart sellng iPhone 3G for 97 dollars




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement