Robert Mutel, professor in the University of Iowa College of Liberal Arts and Sciences Department of Physics and Astronomy, and his graduate student William Peterson of Marshalltown, Iowa, spearheaded the research, which included astronomers from New Mexico and Switzerland. They published their findings in the Jan. 14 issue of the Journal Nature.
Mutel said that the image of the coronal loop (roughly resembling a rainbow) was made of the star Algol, a well-known variable star in the constellation Perseus. Algol (Arabic for demon) is also know as the Demon Star and is one of the first eclipsing binary stars and variable stars to have been discovered. Its brightness as seen from Earth temporarily decreases roughly every 69 hours.
"We imaged the coronal loop using a global array of radio telescopes," Mutel said. "We also carefully compared radio and optical coordinates, so we know where the radio source was located with respect to the star."
"Earlier attempts to image stellar coronal loops in visible light resulted in fuzzy blobs, but we used a global array of radio telescopes to make a series of images over a six-month period. High resolution radio interferometery allows us to image features which would otherwise be undetectable."
The instrument Mutel and Peterson used is actually a combination of 13 radio telescopes linked by computer. They include the 10-telescope VLBA (Very Long Baseline Array) composed of telescopes in Mauna Kea, Hawaii, St. Croix in the Virgin Islands, and North Liberty, Iowa; a 100-meter instrument at the Max Planck Institute for Radio Astronomy near Bonn, Germany; the National Radio Astronomy Observatory (NRAO) at Green Bank, W. Va.; and the NRAO's Very Large Array (VLA) in New Mexico.
Despite the impressive coordination of telescopes dedicated to capturing information from Algol, making sense out of all the data is difficult. "Learning how to take radio data and turn it into an image is a challenge," Peterson said.
Interpreting the data is perhaps just as challenging. Mutel noted that the coronal loop at Algol is similar to those at the sun, but the magnetic field at Algol is about 1,000 times more powerful.
Peterson said that the larger-than-predicted size of the coronal loop is probably due to the tidal effects of the companion star distorting the loop and stretching it. Additionally, the companion star causes the coronal loop to continually face the companion star.
Mutel said that a better understanding of Algol's coronal loops might help us to better understand the sun, something that could benefit a wide range of human activities.
"We really need to understand our sun," he said. "The sun is close to us and can be studied, but it is only one star. By studying other stars, we will be able to put its behavior into a broader context.
"Coronal loops at the sun are associated with sunspots. Sunspots, in turn, are associated with space weather, a constant stream of charged particles flowing outward from the sun. The intensity of solar radiation can affect everything from communications systems that rely on satellites to the health of astronauts who must sometimes work in space."
Mutel said that future research likely will focus on obtaining coronal loop images at other stars.
"Perhaps we can work toward predictions of space weather. Maybe we can better understand the physics of space weather through a study of coronal loops," he said.
Gary Galluzzo | EurekAlert!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy