 |
|
Lightest exoplanet yet discovered
April 22, 2009Well-known exoplanet researcher Michel Mayor today announced the discovery of the lightest exoplanet found so far. The planet, "e"¯, in the famous system Gliese 581, is only about twice the mass of our Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist. These amazing discoveries are the outcome of more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile.
"The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the 'habitable zone' -- a region around the host star with the right conditions for water to be liquid on a planet's surface"¯, says Michel Mayor from the Geneva Observatory, who led the European team to this stunning breakthrough.
Being so close to its host star, the planet is not in the habitable zone. But another planet in this system appears to be. From previous observations -- also obtained with the HARPS spectrograph at ESO's La Silla Observatory and announced two years ago -- this star was known to harbour a system with a Neptune-sized planet (ESO 30/05) and two super-Earths (ESO 22/07). With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. "Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,"¯ says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. "'d' could even be covered by a large and deep ocean -- it is the first serious 'water world' candidate,"¯ continued Udry.
The gentle pull of an exoplanet as it orbits the host star introduces a tiny wobble in the star's motion -- only about 7 km/hour, corresponding to brisk walking speed -- that can just be detected on Earth with today's most sophisticated technology. Low-mass red dwarf stars such as Gliese 581 are potentially fruitful hunting grounds for low-mass exoplanets in the habitable zone. Such cool stars are relatively faint and their habitable zones lie close in, where the gravitational tug of any orbiting planet found there would be stronger, making the telltale wobble more pronounced. Even so, detecting these tiny signals is still a challenge, and the discovery of Gliese 581 e and the refinement of Gliese 581 d's orbit were only possible due to HARPS's unique precision and stability.
"It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 -- the one around 51 Pegasi,"¯ says Mayor. "The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years."¯
The astronomers are confident that they can still do better. "With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,"¯ says Bonfils. "The hunt continues."¯
Notes
This discovery was announced today at the JENAM conference during the European Week of Astronomy & Space Science, which is taking place at the University of Hertfordshire, UK. The results have also been submitted for publication in the research journal Astronomy & Astrophysics ("The HARPS search for southern extra-solar planets: XVIII. An Earth-mass planet in the GJ 581 planetary system"¯, by Mayor et al., 2009).
The team is composed of M. Mayor, S. Udry, C. Lovis, F. Pepe and D. Queloz (Geneva Observatory, Switzerland), X. Bonfils, T. Forveille , X. Delfosse, H. Beust and C. Perrier (LAOG, France), N. C. Santos (Centro de Astrofisica,Universidade de Porto), F. Bouchy (IAP, Paris, France) and J.-L. Bertaux (Service d'AƩronomie du CNRS, VerriƮres-le-Buisson, France).
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in the Atacama Desert region of Chile: La Silla, Paranal and Chajnantor.
ESO
Exoplanet Current Events and Exoplanet News RSS32 new exoplanets found
The latest batch of exoplanets announced today comprises no less than 32 new discoveries. Including these new results, data from HARPS have led to the discovery of more than 75 exoplanets in 30 different planetary systems.
Simulation suggests rocky exoplanet has bizarre atmosphere
So accustomed are we to the sunshine, rain, fog and snow of our home planet that we find it next to impossible to imagine a different atmosphere and other forms of precipitation.
First solid evidence for a rocky exoplanet
The longest set of HARPS measurements ever made has firmly established the nature of the smallest and fastest-orbiting exoplanet known, CoRoT-7b, revealing its mass as five times that of Earth's.
Seeing the Cosmos Through
NASA's Spitzer Space Telescope has taken its first shots of the cosmos since warming up and starting its second career. The infrared telescope ran out of coolant on May 15, 2009, more than five-and-half-years after launch, and has since warmed to a still-frosty 30 Kelvin (about minus 406 Fahrenheit).
New technique could find water on Earth-like planets orbiting distant suns
Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter.
COROT finds exoplanet orbiting Sun-like star
A team of European scientists working with COROT have discovered an exoplanet orbiting a star slightly more massive than the Sun. After just 555 days in orbit, the mission has now observed more than 50 000 stars and is adding significantly to our knowledge of the fundamental workings of stars.
The Drifting Star
By studying in great detail the 'ringing' of a planet-harbouring star, a team of astronomers using ESO's 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way.
New rocky planet found in constellation Leo
Spanish and UCL (University College London) scientists have discovered a possible terrestrial-type planet orbiting a star in the constellation of Leo. The new planet, which lies at a distance of 30 light years from the Earth, has a mass five times that of our planet but is the smallest found to date. One full day on the new planet would be equivalent to three weeks on Earth.
Polarization technique focuses limelight
An international team of astronomers, led by Professor Svetlana Berdyugina of ETH Zurich's Institute of Astronomy, has for the first time ever been able to detect and monitor the visible light that is scattered in the atmosphere of an exoplanet.
COROT surprises a year after launch
The space-borne telescope, COROT (Convection, Rotation and planetary Transits), has just completed its first year in orbit. The observatory has brought in surprises after over 300 days of scientific observations.
More Exoplanet Current Events and Exoplanet News Articles
 |
Exoplanets: Detection, Formation, Properties, Habitability (Springer Praxis Books / Astronomy and Planetary Sciences) by John W. Mason (Author), John W. Mason (Editor) This edited, multi-author volume will be an invaluable introduction and reference to all key aspects in the field of exoplanet research. The reviews cover: Detection methods and properties of known exoplanets, Detection of extrasolar planets by gravitational microlensing. The formation and evolution of terrestrial planets in protoplanetary and debris disks. The brown dwarf-exoplanet connection. Formation, migration mechanisms and properties of hot Jupiters. Dynamics of multiple exoplanet systems. Doppler exoplanet surveys. Searching for exoplanets in the stellar graveyard. Formation and habitability of extra solar planets in multiple star systems. Exoplanet habitats and the possibilities for life. Moons of exoplanets: habitats for life. Contributing authors: Rory Barnes... |
 |
New Worlds in the Cosmos: The Discovery of Exoplanets by Michel Mayor (Author), Pierre-Yves Frei (Author), Boud Roukema (Translator) With the discovery in 1995 of the first planet orbiting another star, we now realize that planets are not unique to our own Solar System. For centuries, humanity has wondered whether we are alone in the Universe. We are now finally one step closer to knowing the answer. The quest for exoplanets is an exciting one because it holds the possibility that one day we might find life elsewhere in the Universe, born in the light of another sun. Written from the perspective of one of the pioneers of this scientific adventure, this exciting account describes the development of the modern observing technique that has enabled astronomers to find so many planets orbiting around other stars. It reveals the wealth of new planets that have now been discovered outside our Solar System, and the meaning of... |
 |
Through The Land Of Talking Lavalamps and Purple Wildebeest (Original Mix) Exoplanet (Primary Contributor) |
 |
Exoplanets: Detection, Formation and Dynamics (IAU S249) (Proceedings of the International Astronomical Union Symposia and Colloquia) by Yi-Sui Sun (Editor), Sylvio Ferraz-Mello (Editor), Ji-Lin Zhou (Editor) In the 12 years since the first discovery of an exoplanet around a main sequence star (51 Peg), more than 270 exoplanets have been detected. The proceedings of IAU Symposium 249 present the latest theoretical and observational advances in the field of exoplanet research, including the ongoing and future projects such as CoRoT and Kepler. The volume opens with a review of exoplanet detection and orbital determination techniques, before looking at the physics of gas giant atmospheres and close-in stars. The topics of planet formation, migration and the dynamical evolution of protoplanetary disks and multi-planet systems are also covered in detail. IAU S249 is a useful reference for the graduate students and researchers working in the exciting field of exoplanet study. |
 |
Artist's Impression of a Unique Type of Exoplanet Photographic Poster Print by Stocktrek Images, 24x24 by Art.com Art.com is the world's largest retailer of art prints, posters, photographs, and framed artwork. With our huge selection of over 400,000 prints, you'll easily find the perfect piece for your home, office, or classroom. Our art is printed on quality paper. When you order framed artwork, the piece is built by our team of in-house professionals. Visit our Amazon store today at www.amazon.com/artdotcom to find Special Offers and search for products based on 'Artist Name' and 'Subject Categories' such as Movie, Music, Vintage, TV, Children, Travel, Kitchen, Museum Art, Animals, Floral, Motivational, and Sports. Art.com is dedicated to providing you with high quality products and service by offering you 100% satisfaction guaranteed. We ship internationally to over 80 countries. Decorate your... |
 |
Wandering Stars: About Planets And Exo-planets, An Introductory Notebook by George H. A. Cole (Author) The space vehicle spectaculars of recent years have been revealing the full scope and beauty of our own solar system but have also shown that a growing number of other stars too have planetary bodies orbiting around them. The study of these systems is just beginning. It seems that our galaxy contains untold numbers of planets, and presumably other galaxies will be similar to our own. Our solar system contains life, on Earth: do others as well? Such questions excite modern planetary scientists and astro-biologists. This situation is a far cry from ancient times when the five planets that can be seen from Earth without a telescope were called the "wandering stars". This notebook-cum-workbook provides an introduction to those profound and still-developing modern studies. Written by an... |
 |
The Detection and Exploration of Planets from the Trans-atlantic Exoplanet Survey by Francis O'Donovan (Author) |
 |
Exoplanets and Disks: Their Formation and Diversity: Proceedings of the International Conference (AIP Conference Proceedings / Astronomy and Astrophysics) by Tomonori Usuda (Editor), Motohide Tamura (Editor), Miki Ishii (Editor) Protoplanetary disks around young stars are the sites of planetary formation. Recent high spatial resolution observations from both ground and space have revealed wide varieties of disk morphology and composition. This diversity of disk properties is certainly the seeds for the well known diversity of about 350 exoplanets so far detected. Encouraged with the recent success of direct imaging of exoplanets, next generation high-contrast instruments on the 8-m class telescopes are starting to fully explore direct observations of both exoplanets and disks. This international conference was held to give an overview of this rapidly developing field and promote discussion on future studies among observers, theorists, and instruments. |
 |
Floatopia Exoplanet (Primary Contributor) |
 |
Gas-Giant Exoplanet Transiting Across the Face of Its Star Photographic Poster Print by Stocktrek Images, 16x16 by AllPosters.com AllPosters.com is the world's #1 seller of posters, prints, photographs, specialty products and framed art. We're dedicated to bringing our customers the best selection of high quality wall dƩcor that is perfect for their home or office. Browse our catalog of over 300,000 items that include entertainment and specialty posters, decorative prints, and art reproductions. Whether you're looking for your favorite movie or music poster, a framed Monet reproduction, or a print of the Eiffel Tower you will find it at AllPosters.com. Visit our Amazon store today at www.amazon.com/allposters to find Special Offers and search by subject category or artist. AllPosters.com provides unmatched service with a 100% satisfaction guarantee. We ship internationally to over 80 countries. Decorate your... |
| © 2009 BrightSurf.com |