Join Date: May 2004
Location: that interweb thing
And two new sets of images, from two scopes/methods, of two interstellar locations... which may demonstrate the same phenomenon at different scales...
From Hubble, a suspected 'mystery object
'... perhaps an eclipsing brown dwarf and companion
Originally Posted by WIRED
A mysterious object discovered near a brown dwarf doesn’t fit into any known astronomical category.
The newly discovered mystery companion forms a binary system with the brown dwarf, located 460 light-years away in the Taurus star-forming system. The object is too light to be another brown dwarf, but it’s too young to have formed by accretion, the way a typical planet does.
“Although this small companion appears to have a mass that is comparable to the mass of planets around stars, we don’t think it formed like a planet,” said astronomer Kevin Luhman of Penn State University, co-author of the study April 5 in The Astrophysical Journal. “This seems to indicate that there are two different ways for nature to make small companions.”
Luhman’s team made the discovery with the Hubble Space Telescope and the Gemini Observatory.
The new object and its companion brown dwarf are orbiting as a binary pair, 15 astronomical units from each other. If they were superimposed on our solar system, the companion would be orbiting midway between Saturn and Uranus. The oddball object’s mass is somewhere between five and 10 Jupiter masses, making it too small to fuse deuterium. The International Astronomical Union currently uses this fusion line, which occurs at about 13 Jupiter masses, as the defining characteristic of a brown dwarf.
But the object appears to be around the same age as its binary partner, which doesn’t fit conventional ideas about planet formation. Traditional theories describe planets forming from the gaseous disk that swirls around the equator of a newly formed star. Particles in the gas and dust cloud collide, and gradually accrete into larger objects, eventually becoming planets. These rocky planets can grow into sizes up to 10 Earth masses before they become gas giants.
And 1 million years is much shorter than the expected time for a planet to be born this way. Planets can form this quickly when there is a gravitational instability in the gaseous disk, but the brown dwarf’s disk probably didn’t have enough material to form a planet larger than a single Jupiter mass.
“It looks like this new system formed by the collapse and fragmentation process that forms binary star systems,” Alan Boss, president of the IAU Commission on Extrasolar Planets said in an e-mail to Wired.com. Boss theorized that these sorts of planet-sized objects exist in a paper published in 2001.
“While people like to use the ‘p-word’ to describe objects with masses below 13 Jupiter masses, given the attention given to exoplanets these days, they should more properly be called ’sub-brown dwarfs,’” Boss said.
Because this strange object seems more likely to have formed the same way as its binary partner, the brown dwarf, Luhman believes it is probably best classified as a very small brown dwarf.
“This object, because it formed like a star, its composition is probably the same throughout,” Luhman said. This homogenous composition is in stark contrast to the innards of gas giants, like Jupiter, which probably have a heavy-element rocky core surrounded by a gaseous shell composed mainly of hydrogen and helium.
The presence of another nearby binary system, of a red star and a brown dwarf, supports Luhman’s theory. It seems to have been formed around the same time as the mystery pair, indicating that all four may have formed the same way, as stars.
“This configuration — two tight pairs that are widely separated from each other — is called a hierarchical configuration and is commonly seen in quadruple star systems,” Luhman said.
Images: 1) NASA, ESA, K. Todorov, K. Luhman, Penn State University. 2) Artist’s rendering from Gemini Observatory/L. Cook.
And via the magic of interferometry to combine images greater than the sum of component telescopes (no matter how big), what may be dust accreting from an orbiting companion back to the binary primary star
Eclipse of nearby star photographed for first time.
Originally Posted by BBC
The first close-up image of an eclipse beyond the solar system has been captured by scientists.
Scientists said the eclipse is caused by a thin disc of opaque dust
Astronomers at the University of St Andrews worked on an international study of the star Epsilon Aurigae, from the Auriga constellation.
Every 27 years it becomes dimmer, a phenomenon which lasts for two years.
The physicists combined light from four telescopes to get the first image of the eclipse, which is 140 times sharper than images from the Hubble telescope.
The team described the discovery as a "terrifying image, like something from a Tolkein book".
'Kill the light'
The eclipse was first observed by the German astrologer Johann Fritsch in 1821.
Dr Ettore Pedretti and Dr Nathalie Thureau, from St Andrews, took part in the research, which was led by Brian Kloppenborg from the University of Denver.
Dr Pedretti said: "From the image, we can confirm that the eclipse of Epsilon Aurigae is caused by a thin disc of opaque dust trailed by a massive and unseen companion.
"Like David, tiny particles of dust are able to kill the light of this 'Goliath' star."
Dr Thureau designed some of the optics for the light-combining technique used to view the star, which is called optical interferometry.
"With this image we have solved a 180-year-old mystery," she said.
"Astronomers have been puzzled for more than a century about this star and we took two pictures that may finally solve the mystery.
"In fact we will continue to capture images since the eclipse lasts about two years."
The two academics intend to form the first group in Scotland to build instruments for optical and infrared interferometry.
"Our aim is to exploit existing interferometers around the world in order to take detailed pictures of distant and interesting astronomical objects that are not achievable even with the largest single telescopes," explained Dr Pedretti.
The research will be published in the journal, Nature.
Of course, both might be due to Death Star Space Bat Shadow puppetry
other eclipsing phenomenon... but something
occluded the light from those stars (on schedule
in the 2nd case).
Which means that even if speculation about the theoretical 'causes' is incorrect, the modeling of predictable orbital mechanics from light years away (enough for 'photos
') is pretty damn impressive.
All those who believe in telekinesis, raise my hand.
Last edited by curiousuburb : 2010-04-08 at 09:09.