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




EXO WORLDS
Astronomers Image Lowest-mass Exoplanet Around a Sun-like Star
by Francis Reddy for Goddard Space Flight Center
Greenbelt MD (SPX) Aug 07, 2013


Glowing a dark magenta, the newly discovered exoplanet GJ 504b weighs in with about four times Jupiter's mass, making it the lowest-mass planet ever directly imaged around a star like the sun. Image Credit: NASA's Goddard Space Flight Center/S. Wiessinger.

Using infrared data from the Subaru Telescope in Hawaii, an international team of astronomers has imaged a giant planet around the bright star GJ 504. Several times the mass of Jupiter and similar in size, the new world, dubbed GJ 504b, is the lowest-mass planet ever detected around a star like the sun using direct imaging techniques.

"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a color reminiscent of a dark cherry blossom, a dull magenta," said Michael McElwain, a member of the discovery team at NASA's Goddard Space Flight Center in Greenbelt, Md. "Our near-infrared camera reveals that its color is much more blue than other imaged planets, which may indicate that its atmosphere has fewer clouds."

GJ 504b orbits its star at nearly nine times the distance Jupiter orbits the sun, which poses a challenge to theoretical ideas of how giant planets form.

According to the most widely accepted picture, called the core-accretion model, Jupiter-like planets get their start in the gas-rich debris disk that surrounds a young star. A core produced by collisions among asteroids and comets provides a seed, and when this core reaches sufficient mass, its gravitational pull rapidly attracts gas from the disk to form the planet.

While this model works fine for planets out to where Neptune orbits, about 30 times Earth's average distance from the sun (30 astronomical units, or AU), it's more problematic for worlds located farther from their stars. GJ 504b lies at a projected distance of 43.5 AU from its star; the actual distance depends on how the system tips to our line of sight, which is not precisely known.

"This is among the hardest planets to explain in a traditional planet-formation framework," explained team member Markus Janson, a Hubble postdoctoral fellow at Princeton University in New Jersey. "Its discovery implies that we need to seriously consider alternative formation theories, or perhaps to reassess some of the basic assumptions in the core-accretion theory."

The research is part of the Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS), a project to directly image extrasolar planets and protoplanetary disks around several hundred nearby stars using the Subaru Telescope on Mauna Kea, Hawaii. The five-year project began in 2009 and is led by Motohide Tamura at the National Astronomical Observatory of Japan (NAOJ).

While direct imaging is arguably the most important technique for observing planets around other stars, it is also the most challenging.

"Imaging provides information about the planet's luminosity, temperature, atmosphere and orbit, but because planets are so faint and so close to their host stars, it's like trying to take a picture of a firefly near a searchlight," explained Masayuki Kuzuhara at the Tokyo Institute of Technology, who led the discovery team.

The SEEDS project images at near-infrared wavelengths with the help of the telescope's novel adaptive optics system, which compensates for the smearing effects of Earth's atmosphere, and two instruments: the High Contrast Instrument for the Subaru Next Generation Adaptive Optics and the InfraRed Camera and Spectrograph. The combination allows the team to push the boundary of direct imaging toward fainter planets.

A paper describing the results has been accepted for publication in The Astrophysical Journal and will appear in a future issue.

The researchers find that GJ 504b is about four times more massive than Jupiter and has an effective temperature of about 460 degrees Fahrenheit (237 Celsius).

It orbits the G0-type star GJ 504, which is slightly hotter than the sun and is faintly visible to the unaided eye in the constellation Virgo. The star lies 57 light-years away and the team estimates the systems is about 160 million years, based on methods that link the star's color and rotation period to it age.

Young star systems are the most attractive targets for direct exoplanet imaging because their planets have not existed long enough to lose much of the heat from their formation, which enhances their infrared brightness.

"Our sun is about halfway through its energy-producing life, but GJ504 is only one-thirtieth its age," added McElwain. "Studying these systems is a little like seeing our own planetary system in its youth."

Paper (preprint): Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504.

.


Related Links
List of imaged exoplanets in The Extrasolar Planets Encyclopaedia
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
New Explorer Mission Chooses the 'Just-Right' Orbit
Greenbelt MD (SPX) Aug 06, 2013
Principal Investigator George Ricker likes to call it the "Goldilocks orbit" - it's not too close to Earth and her Moon, and it's not too far. In fact, it's just right. And as a result of this never-before-used orbit - advanced and fine-tuned by NASA engineers and other members of the Transiting Exoplanet Survey Satellite (TESS) team - the Explorer mission led by Ricker will be perfectly p ... read more


EXO WORLDS
NASA Selects Launch Services Contract for OSIRIS-REx Mission

Environmental Controls Move Beyond Earth

Bad night's sleep? The moon could be to blame

Moon Base and Beyond

EXO WORLDS
Big ice may explain Mars' double-layer craters

Full Curiosity Traverse Passes One-Mile Mark

Curious craters on Mars said result of impacts into ancient ice

NASA Begins Launch Preparations for Next Mars Mission

EXO WORLDS
Study: Teleportation would have a slight time-to-transmit problem

NASA technologist makes traveling to hard-to-reach destinations easier

First Liquid Hydrogen Tank Barrel Segment for SLS Core Completed

Tenth Parachute Test for NASA's Orion Adds 10,000 Feet of Success

EXO WORLDS
China launches three experimental satellites

Medical quarantine over for Shenzhou-10 astronauts

China's astronauts ready for longer missions

Chinese probe reaches record height in space travel

EXO WORLDS
NASA's Firestation on way to ISS

Weekly recap from the International Space Station expedition lead scientist

NSBRI Wants Ideas To Support Space Crew Health and Performance

NASA narrows list of possible culprits in spacesuit water leak

EXO WORLDS
Next Ariane 5 is readied to receive its dual-satellite payload

Russia to restart Proton rocket launches after crash

Japanese rocket takes supplies, robot to space station

SpaceX Awarded Launch Reservation Contract for Largest Canadian Space Program

EXO WORLDS
Astronomers Image Lowest-mass Exoplanet Around a Sun-like Star

New Explorer Mission Chooses the 'Just-Right' Orbit

'Blinking' stellar system may yield clues to planet formation

Pulsating star sheds light on exoplanet

EXO WORLDS
New 'weird' material may be new class of solids, researchers say

Large Area Picosecond Photodetectors push timing envelope

Seeing depth through a single lens

Altering organic molecules' interaction with light




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