Featured Research

from universities, journals, and other organizations

Lightest exoplanet to be directly observed so far? Faint object moves near bright star

Date:
June 3, 2013
Source:
European Southern Observatory - ESO
Summary:
A team of astronomers using the European Southern Observatory's Very Large Telescope has imaged a faint object moving near a bright star. With an estimated mass of four to five times that of Jupiter, it would be the least massive planet to be directly observed outside the Solar System. The discovery is an important contribution to our understanding of the formation and evolution of planetary systems.

This image from ESO's Very Large Telescope (VLT) shows the newly discovered planet HD95086 b, next to its parent star. The observations were made using NACO, the adaptative optics instrument for the VLT in infrared light, and using a technique called differential imaging, which improves the contrast between the planet and its dazzling host star. The star itself has been removed from the picture during processing to enhance the view of the faint exoplanet and its position is marked. The exoplanet appears at the lower left. The blue circle is the size of the orbit of Neptune in the Solar System. The star HD 95086 has similar properties to Beta Pictoris and HR 8799 around which giant planets have previously been imaged at separations between 8 and 68 astronomical units. These stars are all young, more massive than the Sun, and surrounded by a debris disc.
Credit: ESO/J. Rameau

A team of astronomers using ESO's Very Large Telescope has imaged a faint object moving near a bright star. With an estimated mass of four to five times that of Jupiter, it would be the least massive planet to be directly observed outside the Solar System. The discovery is an important contribution to our understanding of the formation and evolution of planetary systems.

Although nearly a thousand exoplanets have been detected indirectly -- most using the radial velocity or transit methods [1] -- and many more candidates await confirmation, only a dozen exoplanets have been directly imaged. Nine years after ESO's Very Large Telescope captured the first image of an exoplanet, the planetary companion to the brown dwarf 2M1207, the same team has caught on camera what is probably the lightest of these objects so far [2][3].

"Direct imaging of planets is an extremely challenging technique that requires the most advanced instruments, whether ground-based or in space," says Julien Rameau (Institut de Planetologie et d'Astrophysique de Grenoble, France), first author of the paper announcing the discovery. "Only a few planets have been directly observed so far, making every single discovery an important milestone on the road to understanding giant planets and how they form."

In the new observations, the likely planet appears as a faint but clear dot close to the star HD 95086. A later observation also showed that it was slowly moving along with the star across the sky. This suggests that the object, which has been designated HD 95086 b, is in orbit around the star. Its brightness also indicates that it has a predicted mass of only four to five times that of Jupiter.

The team used NACO, the adaptive optics instrument mounted on one of the 8.2-metre Unit Telescopes of ESO's Very Large Telescope (VLT). This instrument allows astronomers to remove most of the blurring effects of the atmosphere and obtain very sharp images. The observations were made using infrared light and a technique called differential imaging, which improves the contrast between the planet and dazzling host star.

The newly discovered planet orbits the young star HD 95086 at a distance of around 56 times the distance from Earth to the Sun, twice the Sun-Neptune distance. The star itself is a little more massive than the Sun and is surrounded by a debris disc. These properties allowed astronomers to identify it as an ideal candidate to harbour young massive planets. The whole system lies some 300 light-years away from us.

The youth of this star, just 10 to 17 million years, leads astronomers to believe that this new planet probably formed within the gaseous and dusty disc that surrounds the star. "Its current location raises questions about its formation process. It either grew by assembling the rocks that form the solid core and then slowly accumulated gas from the environment to form the heavy atmosphere, or started forming from a gaseous clump that arose from gravitational instabilities in the disc." explains Anne-Marie Lagrange, another team member. "Interactions between the planet and the disc itself or with other planets may have also moved the planet from where it was born."

Another team member, Gaël Chauvin, concludes, "The brightness of the star gives HD 95086 b an estimated surface temperature of about 700 degrees Celsius. This is cool enough for water vapour and possibly methane to exist in its atmosphere. It will be a great object to study with the forthcoming SPHERE instrument on the VLT. Maybe it can also reveal inner planets in the system -- if they exist." [4]

Notes:

[1] Astronomers have already confirmed the existence of nearly a thousand planets orbiting stars other than the Sun. Almost all were found using indirect methods that could detect the effects of the planets on their parent stars -- the dips of brightness produced when planets crossed in front of them (the transit method), or the wobbling caused by the gravitational pull of planets in their orbits (the radial velocity method). So far, only a dozen exoplanets have been directly observed.

[2] Fomalhaut b may have a lower mass, but its brightness seems to be contaminated by light reflected from the surrounding dust, making the precise determination of its mass uncertain.

[3] This team also has observed an exoplanet around the star Beta Pictoris (eso1024 -- http://www.eso.org/public/news/eso1024/), as well as several others.

[4] SPHERE (http://www.eso.org/sci/facilities/develop/instruments/sphere.html) is a second generation adaptive optics instrument that will be installed on the VLT in late 2013.


Story Source:

The above story is based on materials provided by European Southern Observatory - ESO. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Rameau, G. Chauvin, A.-M. Lagrange, A. Boccaletti, S. P. Quanz, M. Bonnefoy, J. H. Girard, P. Delorme, S. Desidera, H. Klahr, C. Mordasini, C. Dumas, M. Bonavita, T. Meshkat, V. Bailey, M. Kenworthy. Discovery of a probable 4-5 Jupiter-mass exoplanet to HD 95086 by direct-imaging. The Astrophysical Journal Letters, 2013; (accepted)

Cite This Page:

European Southern Observatory - ESO. "Lightest exoplanet to be directly observed so far? Faint object moves near bright star." ScienceDaily. ScienceDaily, 3 June 2013. <www.sciencedaily.com/releases/2013/06/130603091714.htm>.
European Southern Observatory - ESO. (2013, June 3). Lightest exoplanet to be directly observed so far? Faint object moves near bright star. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2013/06/130603091714.htm
European Southern Observatory - ESO. "Lightest exoplanet to be directly observed so far? Faint object moves near bright star." ScienceDaily. www.sciencedaily.com/releases/2013/06/130603091714.htm (accessed April 24, 2014).

Share This



More Space & Time News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Risk of Asteroid Hitting Earth Higher Than Thought, Study Shows

Reuters - US Online Video (Apr. 23, 2014) — A group of space explorers say the chance of a city-obliterating asteroid striking Earth is higher than scientists previously believed. Deborah Gembara reports. Video provided by Reuters
Powered by NewsLook.com
Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) — The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
Two US Astronauts Step out on Spacewalk for ISS Repairs

Two US Astronauts Step out on Spacewalk for ISS Repairs

AFP (Apr. 23, 2014) — Two US astronauts stepped out on a brief spacewalk Wednesday to install a backup computer at the International Space Station after one failed earlier this month. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) — NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins