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.
Sungrazing comets, comprised 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.
Robert Sanders | EurekAlert!
Exoplanet stepping stones
21.11.2018 | W. M. Keck Observatory
First diode for magnetic fields
21.11.2018 | Universität Innsbruck
Innsbruck quantum physicists have constructed a diode for magnetic fields and then tested it in the laboratory. The device, developed by the research groups led by the theorist Oriol Romero-Isart and the experimental physicist Gerhard Kirchmair, could open up a number of new applications.
Electric diodes are essential electronic components that conduct electricity in one direction but prevent conduction in the opposite one. They are found at the...
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
21.11.2018 | Life Sciences
21.11.2018 | Medical Engineering
21.11.2018 | Physics and Astronomy