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Astronomers Confirm the First Image of a Planet Outside of Our Solar System

Written by Everything Science
May 01, 2005 at 12:23 PM
An international team of astronomers reports today confirmation of the discovery of a giant planet, approximately five times the mass of Jupiter, that is gravitationally bound to a young brown dwarf. This puts an end to a year long discussion on the nature of this object, which started with the detection of a red object close to the brown dwarf. In February and March of this year, the astronomers took new images of the young brown dwarf and its giant planet companion with the state-of-the-art NACO instrument on ESO's Very Large Telescope in northern Chile. The planet is near the southern constellation of Hydra and approximately 200 light years from Earth. "Our new images show convincingly that this really is a planet, the first planet that has ever been imaged outside of our solar system," tells Gael Chauvin, astronomer at ESO and leader of the team of astronomers who conducted the study. (0) Comments posted about this in the forum
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Is Thermal Emission in Gamma-Ray Bursts Ubiquitous?

Written by Felix Ryde
Apr 23, 2005 at 11:25 PM
The prompt emission of gamma-ray bursts has yet defied any simple explanation, despite the presence of a rich observational material and great theoretical efforts. Here we show that all the types of spectral evolution and spectral shapes that have been observed can indeed be described with one and the same model, namely a hybrid model of a thermal and a non-thermal component. We further show that the thermal component is the key emission process determining the spectral evolution. Even though bursts appear to have a variety of, sometimes complex, spectral evolutions, the behaviors of the two separate components are remarkably similar for all bursts, with the temperature describing a broken power-law in time. The non-thermal component is consistent with emission from a population of fast cooling electrons emitting optically-thin synchrotron emission or non-thermal Compton radiation. This indicates that these behaviors are the fundamental and characteristic ones for gamma-ray bursts. (0) Comments posted about this in the forum
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New species discovered - Scientists call for woodland management rethink

Written by Everything Science

Apr 19, 2005 at 12:00 AM

Evasive research subjects

When we researchers go into the forest we really need the same kind of nose as these flies to sniff out the sap runs under the bark, because they're often not visible. Someone like Dr Frank Dziock, whose work focuses on these sap-dependent hover flies, cannot simply lie down in a lush flower meadow and wait to see what comes buzzing along, for these insects live hidden within the woods in very special old trees. They live on micro-organisms which are only found in tree sap in contrast to their more widely known relatives. Although many of the other species of hover flies may be mistaken for wasps because of their black and yellow colouring, they cannot sting. Their larvae are actually very useful, as they consume large numbers of aphids. Around 450 different species of hover fly are found in Germany and they have a wide variety of dietary habits.

Brachyopa silviae belongs to the genus Brachyopa, of which only 13 species are known in Europe Photo: AndrÃ© Kuenzelmann/UFZ

A sensation that was almost missed

For the last 12 years Dziock has been investigating the fauna of riparian woodlands. Now, for the first time, the 35-year-old biologist has succeeded in achieving what every entomologist dreams of: the discovery of a new species. Yet the specimen's capture, in the Saalberghau nature reserve by the River Elbe near Dessau, initially seemed quite unspectacular. As part of a research project Frank Dziock had set up an insect trap to examine how hover flies react to flooding. The insects are used here as bio-indicators. At first glance the contents of the trap did not look in any way out of the ordinary. "At first we thought it was a species that was already known. Then we realised that the two tiny spots on the fly's back were clear evidence of an as yet undiscovered species", explains Dziock. On closer examination under the microscope (the fly is only seven millimetres long) it became clear that its body structure was different from all other known species. "So I borrowed the type specimens, known as holotypes and syntypes, of four similar species from the natural history museums in Copenhagen, Stockholm and Oxford and the German Entomological Institute, in order to examine the differences more closely."

Together with hover fly expert, Dieter Doczkal, from Malsch, Frank Dziock wrote a description of the new species. The first description of Brachyopa silviae (Silvia's Brachyopa) was then published in the journal, Volucella. Anyone who discovers a new species can suggest a name for it and Dziock dedicated his discovery to his wife, Silvia, who over the years has had to be very understanding of all the days her husband spends conducting his research in the forests of Central Germany.

New species discovered - Scientists call for woodland management rethink
Orstio April 19th, 2005 - 10:24 PM

Quote

Evasive research subjects

â€œWhen we researchers go into the forest we really need the same kind of nose as these flies to sniff out the sap runs under the bark, because theyâ€™re often not visible.â€ Someone like Dr Frank Dziock, whose work focuses on these sap-dependent hover flies, cannot simply lie down in a lush flower meadow and wait to see what comes buzzing along, for these insects live hidden within the woods in very special old trees. They live on micro-organisms which are only found in tree sap â€“ in contrast to their more widely known relatives. Although many of the other species of hover flies may be mistaken for wasps because of their black and yellow colouring, they cannot sting. Their larvae are actually very useful, as they consume large numbers of aphids. Around 450 different species of hover fly are found in Germany and they have a wide variety of dietary habits.

(1) Comments posted about this in the forum

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Is this a Brown Dwarf or an Exoplanet?

Written by Everything Science

Apr 08, 2005 at 12:00 AM

New Young Sub-stellar Companion Imaged with the VLT

ESO PR Photo 10a/05 shows the VLT NACO image, taken in the Ks-band, of GQ Lupi. The feeble point of light to the right of the star is the newly found cold companion. It is 250 times fainter than the star itself and it located 0.73 arcsecond west. At the distance of GQ Lupi, this corresponds to a distance of roughly 100 astronomical units. North is up and East is to the left.

Since the discovery in 1995 of the first planet orbiting a normal star other than the Sun, there are now more than 150 candidates of these so-called exoplanets known. Most of them are detected by indirect methods, based either on variations of the radial velocity or the dimming of the star as the planet passes in front of it.

Astronomers would, however, prefer to obtain a direct image of an exoplanet, allowing them to better characterize the object's physical nature. This is an exceedingly difficult task, as the planet is generally hidden in the "glare" of its host star.

To partly overcome this problem, astronomers study very young objects. Indeed, sub-stellar objects are much hotter and brighter when young and therefore can be more easily detected than older objects of similar mass.

Based on this approach, it might well be that last year's detection of a feeble speck of light next to the young brown dwarf 2M1207 by an international team of astronomers using the ESO Very Large Telescope is the long-sought bona-fide image of an exoplanet. A recent report based on data from the Hubble Space Telescope seems to confirm this result.

The even more recent observations made with the Spitzer Space Telescope of the warm infrared glows of two previously detected "hot Jupiter" planets is another interesting result in this context. This wealth of new results, obtained in the time span of a few months, illustrates perfectly the dynamic of this field of research.

Re: Is this a Brown Dwarf or an Exoplanet?
remcook April 9th, 2005 - 2:44 AM

whatever it is, we're getting to know more and more about exoplanets!

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