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 Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Seeing the quantum future... literally
16.01.2017 | University of Sydney

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: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>