Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

XO-3b: Supersized planet or oasis in the 'brown dwarf desert'?

31.05.2007
Amateur, professional astronomers find one of the oddest planets on record

The latest find from an international planet-hunting team of amateur and professional astronomers is one of the oddest extrasolar planets ever cataloged -- a mammoth orb more than 13 times the mass of Jupiter that orbits its star in less than four days.

Researchers from the U.S.-based XO Project unveiled the planet, XO-3b, at today's American Astronomical Society meeting in Honolulu. Christopher Johns-Krull, a Rice University astronomer and presenter of the team's results, said, "This planet is really quite bizarre. It is also particularly appropriate to be announcing this find here, since the core of the XO project is two small telescopes operating here in Hawaii."

"Of the 200-plus exoplanets found so far, XO-3b is an oddity in several respects," said XO Project director Peter McCullough, an astronomer at the Space Telescope Science Institute in Baltimore. "It's the largest and most massive planet yet found in such a close orbit, and given the proximity of the orbit to the star, we were surprised to find that the orbit is not circular but significantly elliptical."

Given all its eccentricities, XO-3b is likely to pique the interest of astronomers who study planet formation, McCullough said.

"We are intrigued that its mass is on the boundary between planets and 'brown dwarfs,'" Johns-Krull said, "There's still a lively debate among astronomers about how to classify brown dwarfs." Any stellar mass that's large enough to fuse hydrogen -- anything more than about 80 Jupiter masses -- is a star. Brown dwarfs are massive objects that fall short of being stars.

"The controversy lies at the lower end of the scale," said Johns-Krull, an assistant professor of physics and astronomy at Rice. "Some people believe anything capable of fusing deuterium, which in theory happens around 13 Jupiter masses, is a brown dwarf. Others say it's not the mass that matters, but whether the body forms on its own or as part of a planetary system."

By virtue of their mass, any planet big enough to contend for brown dwarf status should be easy for most planet hunters to spot. That's because astronomers don't actually look for planets when they scan the sky; they generally look for stars that wobble due to the gravitational pull of planets orbiting around them. The larger the planet, the more wobble it creates, so planet hunters using this "radial velocity" method expected to find a lot of brown dwarfs when they started scanning the sky for wobbling stars a decade ago. That hasn't happened, and the dearth of supersized objects has become known in the field as the "brown dwarf desert."

What also makes XO-3b intriguing is the fact that it's a "transiting planet," meaning it passes in front of its star during each orbit. Fewer than two dozen transiting planets have been identified, and XO-3b is the third found by the XO Project, which was designed specifically to look for them.

The XO Project benefits from its partnership between professional and amateur astronomers. The XO Project begins its search with a telescope located on Haleakala summit operated by the Institute for Astronomy of the University of Hawaii. The telescope is created from two commercially available 200-millimeter telephoto camera lenses. Using the Haleakala telescope, XO's professional team first identifies candidate stars that dim ever so slightly from time to time. XO's amateur astronomers observe these candidates over time and look for further evidence that the dimming is due to a transiting planet. Once enough evidence is in place, the professional team uses large telescopes -- the 2.7-meter Harlan J. Smith Telescope and the 11-meter Hobby-Ebberly Telescope, both at the University of Texas McDonald Observatory in West Texas -- to confirm the presence of a transiting planet.

"There are many astrophysical systems out there that mimic transiting planets," McCullough said. "The only way to sort out the real planets from the rest is to observe the stars more carefully. Observation time on big telescopes is scarce, and that's where our amateur partners come in, culling our long lists of candidates down to more manageable size to observe with the big telescopes. The XO Project benefits enormously from the clear skies of Haleakala and the availability of telescopes such as the Hobby-Ebberly, Spitzer, and Hubble and their capable staffs that operate them. The global reach and dedication of our amateur collaborators is especially noteworthy.

"I like to point out that Olympic athletes are amateurs too," McCullough said.

B.J. Almond | EurekAlert!
Further information:
http://www.rice.edu

More articles from Physics and Astronomy:

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Quantum thermometer or optical refrigerator?
23.06.2017 | National Institute of Standards and Technology (NIST)

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 we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>