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




EXO WORLDS
VLTI detects exozodiacal light
by Staff Writers
Paris (SPX) Nov 04, 2014


This artist's view from an imagined planet around a nearby star shows the brilliant glow of exozodiacal light extending up into the sky and swamping the Milky Way. This light is starlight reflected from hot dust created as the result of collisions between asteroids, and the evaporation of comets. The presence of such thick dust clouds in the inner regions around some stars may pose an obstacle to the direct imaging of Earth-like planets in the future. Image courtesy ESO/L. Calcada

Using the Very Large Telescope Interferometer (VLTI) in near-infrared light [1], the team of astronomers observed 92 nearby stars to probe exozodiacal light from hot dust close to their habitable zones and combined the new data with earlier observations [2].

Bright exozodiacal light, created by the glowing grains of hot exozodiacal dust, or the reflection of starlight off these grains, was observed around nine of the targeted stars.

From dark clear sites on Earth, zodiacal light looks like a faint diffuse white glow seen in the night sky after the end of twilight, or before dawn. It is created by sunlight reflected off tiny particles and appears to extend up from the vicinity of the Sun. This reflected light is not just observed from Earth but can be observed from everywhere in the Solar System.

The glow being observed in this new study is a much more extreme version of the same phenomenon. While this exozodiacal light - zodiacal light around other star systems - had been previously detected, this is the first large systematic study of this phenomenon around nearby stars.

In contrast to earlier observations the team did not observe dust that will later form into planets, but dust created in collisions between small planets of a few kilometres in size - objects called planetesimals that are similar to the asteroids and comets of the Solar System. Dust of this kind is also the origin of the zodiacal light in the Solar System.

"If we want to study the evolution of Earth-like planets close to the habitable zone, we need to observe the zodiacal dust in this region around other stars," said Steve Ertel, lead author of the paper, from ESO and the University of Grenoble in France.

"Detecting and characterising this kind of dust around other stars is a way to study the architecture and evolution of planetary systems."

Detecting faint dust close to the dazzling central star requires high resolution observations with high contrast. Interferometry - combining light collected at the exact same time at several different telescopes - performed in infrared light is, so far, the only technique that allows this kind of system to be discovered and studied.

By using the power of the VLTI and pushing the instrument to its limits in terms of accuracy and efficiency, the team was able to reach a performance level about ten times better than other available instruments in the world.

For each of the stars the team used the 1.8-metre Auxiliary Telescopes to feed light to the VLTI. Where strong exozodical light was present they were able to fully resolve the extended discs of dust, and separate their faint glow from the dominant light of the star [3].

By analysing the properties of the stars surrounded by a disc of exozodiacal dust, the team found that most of the dust was detected around older stars. This result was very surprising and raises some questions for our understanding of planetary systems.

Any known dust production caused by collisions of planetesimals should diminish over time, as the number of planetesimals is reduced as they are destroyed.

The sample of observed objects also included 14 stars for which the detection of exoplanets has been reported. All of these planets are in the same region of the system as the dust in the systems showing exozodiacal light. The presence of exozodiacal light in systems with planets may create a problem for further astronomical studies of exoplanets.

Exozodiacal dust emission, even at low levels, makes it significantly harder to detect Earth-like planets with direct imaging. The exozodiacal light detected in this survey is a factor of 1000 times brighter than the zodiacal light seen around the Sun.

The number of stars containing zodiacal light at the level of the Solar System is most likely much higher than the numbers found in the survey. These observations are therefore only a first step towards more detailed studies of exozodiacal light.

"The high detection rate found at this bright level suggests that there must be a significant number of systems containing fainter dust, undetectable in our survey, but still much brighter than the Solar System's zodiacal dust," explains Olivier Absil, co-author of the paper, from the University of Liege. "The presence of such dust in so many systems could therefore become an obstacle for future observations, which aim to make direct images of Earth-like exoplanets."

Notes
[1] The team used the VLTI visitor instrument PIONIER, which is able to interferometrically connect all four Auxiliary Telescopes or all four Unit Telescopes of the VLT at the Paranal Observatory. This led to not only extremely high resolution of the targets but also allowed for a high observing efficiency.

[2] Previous observations were made with the CHARA array - an optical astronomical interferometer operated by the Center for High Angular Resolution Astronomy (CHARA) of the Georgia State University, and its fibred beam combiner FLUOR.

[3] As a by-product, these observations have also led to the discovery of new, unexpected stellar companions orbiting around some of the most massive stars in the sample. "These new companions suggest that we should revise our current understanding of how many of this type of star are actually double," says Lindsay Marion, lead author of an additional paper dedicated to this complementary work using the same data.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
ESO
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




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EXO WORLDS
Yale finds a planet that won't stick to a schedule
New Haven CT (SPX) Oct 31, 2014
For their latest discovery, Yale astronomers and the Planet Hunters program have found a low-mass, low-density planet with a punctuality problem. The new planet, called PH3c, is located 2,300 light years from Earth and has an atmosphere loaded with hydrogen and helium. It is described in the Oct. 29 online edition of The Astrophysical Journal. The elusive orb nearly avoided detection ... read more


EXO WORLDS
China examines the three stages of lunar test run

China gears up for lunar mission after round-trip success

NASA's LRO Spacecraft Captures Images of LADEE's Impact Crater

New lunar mission to test Chang'e-5 technology

EXO WORLDS
NASA's Curiosity Mars Rover Finds Mineral Match

MAVEN Continues Mars Exploration Begun 50 Years Ago by Mariner 4

You can't get to Mars, but your name can

A One Way Trip to Mars

EXO WORLDS
India to launch unmanned crew module in December

Risk-taker Branson battles to protect Virgin brand

Orion Takes Big Step Before Moving to the Launch Pad

NASA Program Enhances Climate Resilience at Agency Facilities

EXO WORLDS
China's Lunar Orbiter Makes Safe Landing, First in 40 Years

China to build global quantum communication network in 2030

China's First Lunar Return Mission A Stunning Success

China completes first mission to moon and back

EXO WORLDS
Station Trio Prepares for Departure amid Ongoing Science

Students text International Space Station using a 20-foot antenna

Student Experiments Lost in Antares Rocket Explosion

NASA to work with cargo partners despite rocket crash

EXO WORLDS
Spaceflight partners with JAMSS to loft 8 CubeSats on JAXA mission

India to test fly bigger space vehicle next month

Soyuz Installed at Baikonur, Expected to Launch Wednesday

Arianespace signs contract with ELV for ten Vega launchers

EXO WORLDS
VLTI detects exozodiacal light

Peering into Planetary Atmospheres

Yale finds a planet that won't stick to a schedule

In a first, astronomers map comets around another star

EXO WORLDS
Five years in space: one satellite, three missions

ESA space ferry moves ISS to avoid debris

Active, biodegradable packaging for oily products

E-waste inferno burning brighter in China's recycling capital




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news 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 All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.