Subscribe free to our newsletters via your
. 24/7 Space News .




EXO WORLDS
UF-led team uses new observatory to characterize low-mass planets orbiting nearby star
by Staff Writers
Gainesville, FL (SPX) Apr 13, 2012


Although Fomalhaut is a much hotter star than the sun, the planets are so far from their host star that they are among the coldest planets known around a normal star. They are thought to be low-mass bodies, but astronomers do not have enough data to tell whether they have a significant amount of hydrogen gas or are mostly rock and ice.

Astronomers have found compelling evidence for two low-mass planets orbiting the nearby star Fomalhaut, just 25 light years from Earth. Twice as massive as the sun and 20 times brighter, Fomalhaut is surrounded by a ring of dust and debris, making it a favorite system for astronomers to study and a natural laboratory for testing planet formation theories.

In 2008, images of Fomalhaut taken by the Hubble Space Telescope led to the discovery of "Fomalhaut b," the first extra solar planet to be directly detected in visible light. At the time, astronomers believed it to be a giant planet, akin to Jupiter or Saturn, but later infrared images failed to detect the planet, meaning that it had to be smaller than Saturn.

UF astronomers, along with scientists from the new Atacama Large Millimeter Array in Chile, known as ALMA, and the National Radio Astronomy Observatory, used ALMA's superior resolution and sensitivity to study the system in unprecedented detail.

Their results indicate that there are not one, but two planets, with masses between that of Mars and a few times larger than Earth, working together to shape the ring of dust.

The new study reveals that the ring is sharply truncated in the inner and outer edges and is only about 16 astronomical units, or AU, wide, or about 16 times the distance between the Earth and the sun.

That may seem large, but the center of the ring is about 140 AU, making the ring relatively very narrow. It also finds that the ring is vertically thin, about one-seventh as tall as it is wide. Those properties give important clues to explain the planetary system of Fomalhaut.

The results are described in a paper to appear this month in the Astrophysical Journal Letters.

"Combining ALMA observations of the ring's shape with computer models, we can place very tight limits on the mass and orbit of any planet near the ring." said Aaron Boley, a Sagan Postdoctoral Fellow at UF and leader of the study. "The masses of the planets must be small so they do not destroy the ring, but their masses cannot be too low or they would not shape the ring."

Although Fomalhaut is a much hotter star than the sun, the planets are so far from their host star that they are among the coldest planets known around a normal star. They are thought to be low-mass bodies, but astronomers do not have enough data to tell whether they have a significant amount of hydrogen gas or are mostly rock and ice.

"ALMA observations show that Fomalhaut's ring is even more narrow and thinner than previously known," said Matthew Payne, an astronomer at the University of Florida who contributed to the study. "Fomalhaut b alone only explains the ring's sharp inner edge. Our analysis suggests that two planets, one interior and one exterior, are shepherding the ring, analogous to how Uranus' moons Cordelia and Ophelia confine Uranus' brightest ring."

The Atacama Large Millimeter/submillimeter Array, located in the Atacama Desert of northern Chile at an altitude of 16,400 feet is the largest astronomical project in existence. Still under construction, ALMA began scientific operations in September.

"ALMA may still be under construction, but it has already proved to be the world's most powerful telescope for observing the universe at millimeter and submillimeter wavelengths of light." said Stuartt Corder, an astronomer at the National Radio Astronomy Observatory and co-author of the study.

"Once ALMA is completed, we will be able to study systems like Fomalhaut with even greater detail, and see through the veil of dust that hides the early stages of planet formation," said co-author Bill Dent, an astronomer at ALMA.

.


Related Links
University of Florida
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








EXO WORLDS
Study On Extrasolar Planet Orbits Suggests That Solar System Structure Is The Norm
Geava, Italy (SPX) Apr 12, 2012
Recently, the HARPS spectrograph and the Kepler satellite made a census of the planetary population around stars like our own, revealing a bounty of planetary systems. A follow-up study lead by members of the EXOEarths team (Centro de Astrofisica da Universidade do Porto - CAUP), in collaboration with Geneva University, did a joint analysis of the data which showed that the planetary orbits in a ... read more


EXO WORLDS
Russia postpones Luna-Glob moon mission

Russia Plans to Launch Lunar Rovers to Moon after 2020

Russia to explore moon

Earth's Other Moons

EXO WORLDS
NASA seeks new ideas for Mars missions

Mars Express - Pit chains on the Tharsis volcanic bulge

Post Solstice Rover Takes The Opportunity For A Wiggle

Russia and Europe give boost to Mars robotic mission

EXO WORLDS
NASA's Human Spaceflight Programs: From Space Shuttle To The Future

Commentary: Innovate or evaporate

United Launch Alliance Announces New Human Launch Services Organization

Private Lunar mission and the future of space tourism

EXO WORLDS
China's Lunar Docking

Shenzhou-9 may take female astronaut to space

China to launch 100 satellites during 2011-15

Three for Tiangong

EXO WORLDS
Commercial Platform Offers Exposure at ISS

Learn to dock ATV the astronaut way

Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)

Busy first days for ATV Edoardo Amaldi

EXO WORLDS
Dragon Expected to Set Historic Course

NASA Awards Launch Contract For Goes-R And Goes-S Missions

Spy satellite-carrying rocket blasts off

Orbital Receives Order for Minotaur I Space Launch Vehicle From USAF

EXO WORLDS
ALMA Reveals Workings of Nearby Planetary System

UF-led team uses new observatory to characterize low-mass planets orbiting nearby star

When Stellar Metallicity Sparks Planet Formation

Study On Extrasolar Planet Orbits Suggests That Solar System Structure Is The Norm

EXO WORLDS
Copper chains: Study reveals Earth's deep-seated hold on copper

Tablet use while watching TV surveyed

Apple denies e-book pricing scheme

How to plaster the world, cheaply!




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement