Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Large asteroid is two orbiting objects

24.10.2003


An asteroid that has eluded astronomers for decades turns out to be an unusual pair of objects traveling together in space, a UCLA planetary scientist and colleagues report.



The asteroid Hermes was rediscovered last week after being lost for 66 years. Now Jean-Luc Margot, a researcher in UCLA’s department of Earth and space sciences, has determined that the asteroid is, in fact, two objects orbiting each other. The two objects together would cover an area approximately the size of Disneyland.

Margot and colleagues are analyzing new radar measurements from the Arecibo Observatory, part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation. The researchers are scheduled to obtain additional measurements Oct. 25–26 from the observatory, located in Puerto Rico.


Hermes makes frequent close approaches to Earth, Venus and Mars, as well as Vesta, the third-largest asteroid in the main asteroid belt between Mars and Jupiter.

While several other asteroids have satellites, the other known binaries with trajectories that cross the orbit of the Earth consist of a large primary asteroid orbited by a much smaller one.

"Hermes is the first asteroid ever discovered in the near-Earth population where the two components are essentially equal in size," Margot said. "It’s a very unusual binary, a puzzle. It may have formed when it swung so close to a planet that it was ripped apart by gravitational forces, but we don’t know for sure. One of our goals is to learn more about the two components and how they rotate about each other in the hopes that we may be able to deduce how Hermes became a double asteroid.

"Because the components are close to each other, they raise appreciable tides in each other and each has slowed down the other’s spin significantly. They are now likely in a doubly synchronous state, where their spin period is equal to their orbital period. This means they constantly present the same face to each other, just like Pluto and its satellite Charon."

A fast-moving bright object was observed in 1937, named Hermes, and went undetected until last week, although it had revolved around the Sun almost 31 times since then, escaping notice, said Brian Marsden, of the Minor Planet Center in Cambridge, Mass.

On Oct. 15, Brian Skiff of the Lowell Observatory Near-Earth-Object Search sighted the mysterious object; Timothy Spahr at the Minor Planet Center identified similarities with the 1937 observations; and Steven Chesley and Paul Chodas at NASA’s Jet Propulsion Laboratory (JPL) linked the observations to Hermes.

The same day, Margot and his team proposed to observe the asteroid with the Arecibo Observatory’s high-powered radar system -- a proposal that was accepted within hours.

The goals of the proposal were to measure precisely the distance and velocity of this object, to improve the knowledge of its trajectory and help trace back its history, to characterize Hermes’ physical properties, and to search for satellites.

Margot and collaborators have been given five sessions at Arecibo and sessions at the Goldstone radar in California to observe Hermes. Due to the urgent nature of the proposal, Margot observed from his home computer while Mike Nolan, Victor Negron, Alice Hine and Don Campbell were at the Arecibo telescope.

Hermes gets as close as 378 000 miles from Earth -- which, in astronomical terms, is quite close, about 1.6 times the distance between Earth and the moon. Orbits can change appreciably over time due to gravitational influences of the planets, noted Mike Nolan, an Arecibo Observatory scientist and member of the team.

Hermes travels on an elliptical orbit and reaches deep into the inner solar system, crossing Venus’ orbit. The new research has made it possible to extend the time interval over which the trajectory can be computed reliably, said Jon Giorgini, a senior engineer at JPL and member of the team.

"As far as impact risk, there is no cause for worry in our lifetimes," Giorgini said. "Over hundreds of thousands, or millions of years, Hermes could impact the Earth, but only if it doesn’t hit Venus first."

Margot and colleagues described their observations and data in an International Astronomical Union Circular this week. Margot’s research is funded by NASA. His co-authors are Michael Nolan, Victor Negron, Alice Hine, Donald Campbell and Ellen Howell at the National Astronomy and Ionosphere Center; Lance Benner, Steven Ostro and Jon Giorgini at JPL; and Brian Marsden at the Minor Planet Center.

Stuart Wolpert | EurekAlert!
Further information:
http://www2.ess.ucla.edu/~jlmargot/NEAs/Hermes

More articles from Physics and Astronomy:

nachricht First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>