Widely spaced telescopes also determined asteroid pair's shapes
When the double asteroid Patroclus-Menoetius passed directly in front of a star on the night of Oct. 20, a team of volunteer astronomers across the U.S. was waiting.
Observing the event, known as an occultation, from multiple sites where each observer recorded the precise time the star was obscured, yielded the first accurate determination of the two objects' size and shape. The analysis was led by Dr. Marc W. Buie, staff scientist in Southwest Research Institute's (SwRI) Space Studies Department in Boulder, Colo.
The team effort was a pilot program of the Research and Education Collaborative Occultation Network (RECON), whose recently announced expansion was made possible through a $1 million National Science Foundation grant.
Managed jointly by SwRI and Cal Poly (California Polytechnic State University), RECON supplies telescopes to schools and citizen scientists in rural western states from north-central Washington to southwest Arizona for occultation observations. With the grant, RECON membership will grow from 13 pilot communities to 40.
The October collaborative observations involved volunteers distributed east-west across the United States. Observers were from the International Occultation Timing Association (IOTA) as well as a subset of RECON's observer team. Eleven of 36 observation sites were able to record the occultation. Seven of those were analyzed to estimate an outline, or an elliptical limb fit, of Patroclus of 125 kilometers (km) by 98 km. Six of the observations were combined for Menoetius and yielded a size of 117 km by 93 km.
"Previous estimates of the shape of the asteroid pair had indicated essentially spherical objects," Buie said. "Our new observations indicate a significantly more non-spherical shape, and that shape is identical for the two bodies."
Based on this occultation data combined with previous data, both objects possess axial ratios of 1.3:1.21:1, which indicates a mostly oblate shape, or one that appears flattened at the poles and slightly bulged at the equator.
"The very similar shapes of the pair suggest that they were both spinning much faster when they formed," Buie said. "The current system is in a doubly synchronous state, much like Pluto and Charon, where they orbit each other in the same time it takes for them to rotate."
This asteroid pair orbits the Sun in the Jupiter Trojan cloud of asteroids at 5 AU, or Astronomical Units, from the Sun. (One AU equals the distance from the Sun to Earth). "It shows striking similarities to objects from the more distant Kuiper Belt, suggesting that perhaps this object was relocated inward at some time in the early history of the solar system," Buie said.
Joe Fohn | 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