Astronomers catch multiple-star system in first stages of formation

Astronomers catch multiple-star system in first stages of formation
Large scale Herschel image of the dust in the region in blue, with the dense gas low resolution image in green, and the dense gas high-resolution image displaying filaments in red. Credit: B. Saxton (NRAO/AUI/NSF)

For the first time, astronomers have caught a multiple-star system in the beginning stages of its formation, and their direct observations of this process give strong support to one of several suggested pathways to producing such systems.

The scientists looked at a cloud of some 800 light-years from Earth, homing in on a core of gas that contains one young protostar and three dense condensations that they say will collapse into in the astronomically-short period of 40,000 years. Of the eventual four stars, the astronomers predict that three may become a stable triple-star system.

"Seeing such a multiple star system in its early stages of formation has been a longstanding challenge, but the combination of the Very Large Array (VLA) and the Green Bank Telescope (GBT) has given us the first look at such a young system," said Jaime Pineda, of the Institute for Astronomy, ETH Zurich, in Switzerland.

The scientists used the VLA and GBT, along with the James Clerk Maxwell Telescope (JCMT) in Hawaii, to study a dense core of gas called Barnard 5 (B5) in a region where young stars are forming in the constellation Perseus. This object was known to contain one young forming star.

When the research team led by Pineda used the VLA to map radio emission from methane molecules, they discovered that filaments of gas in B5 are fragmenting, and the fragments are beginning to form into additional stars that will become a multiple-star system.

"We know that these stars eventually will form a multi-star system because our observations show that these gas condensations are gravitationally bound," Pineda said. "This is the first time we've been able to show that such a young system is gravitationally bound," he added.

Astronomers catch multiple-star system in first stages of formation
Close up of Image 1 to focus in the region forming the stars. Credit: B. Saxton (NRAO/AUI/NSF)

"This provides fantastic evidence that fragmentation of gas filaments is a process that can produce multiple-star systems," Pineda said. Other proposed mechanisms include fragmentation of the main gas core, fragmentation within a disk of material orbiting a young star, and gravitational capture. "We've now convincingly added fragmentation of gas filaments to this list," Pineda added.

The condensations in B5 that will produce stars now range from one-tenth to more than one-third the mass of the Sun, the scientists said. Their separations will range from 3,000 to 11,000 times the Earth-Sun distance.

In a first, astronomers catch a multiple star system in the process of forming
A triple star system forming within a dense gas filament in a numerical simulation modeling a group of forming stars. The color indicates the gas density, where lighter colors are higher densities. Rhe image is about 10,000 astronomical units across where the projected separations between the three objects is about 2,000 and 4,000 AU. Credit: UMass Amherst

The astronomers analyzed the dynamics of the gas condensations and predict that, when they form into stars, they will form a stable system of an inner binary, orbited by a more-distant third star. The fourth star, they suggest, will not long remain part of the .

Astronomers catch multiple-star system in first stages of formation
Artist impression of the results. Left panel shows the star and three dense gas condensations system. Right panel shows the system after the stars are formed out of the condensations. Credit: B. Saxton (NRAO/AUI/NSF)

"Nearly half of all stars are in multiple systems, but catching such systems at the very early stages of formation has been challenging. Thanks to the combination of the VLA and the GBT, we now have some important new insight into how multiple systems form. Our next step will be to look at other star-forming regions using the new capabilities of the VLA and of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile," Pineda said

In addition to Pineda, the international research team included members from the U.S., the UK, Germany, and Chile. The astronomers reported their findings in the 12 February edition of the scientific journal Nature.

Explore further

New studies give strong boost to binary-star formation theory

More information: Pineda JE, Offner SSR, Parker RJ, Arce HG, Goodman AA, Caselli P, Fuller GA, Bourke TL, Corder SA. The formation of a quadruple star system with wide separation, Nature, published online 11 February 2015,
Journal information: Nature

Citation: Astronomers catch multiple-star system in first stages of formation (2015, February 11) retrieved 23 August 2019 from
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Feb 11, 2015
FINALLY and this is just the beginning. man. astronomy is about to enter a great golden age. arguably it already has. but this is just great.

Feb 11, 2015
FINALLY and this is just the beginning. man. astronomy is about to enter a great golden age. arguably it already has. but this is just great.

Unfortunately, all we'll get are pretty picture's. Until mainstream quits using hot gas and gravity in their models, the only "golden age" we will see, is the "golden age of confusion".

Feb 12, 2015
Why are they only interested in showing the results in the pictures? An animation of the model run with like 1 second=1000years would have been too hard to accomplish? They say it's about a 40k year process so they could have made a video spanning 60k from the model runs, but nooo...

I'd like to see that collapse, and see how the conservation of angular momentum plays with the asymmetric matter streams to produce the final orbits of the stars.

Also it's important to see how any planets/planetoids might from when the gas gets compressed as each star ignites and starts to cast off energy and particles into the left-over gas and dust. Surely some will just get blown away, but some will get compressed to form other objects. They didn't even mention that sort of thing.

Apr 03, 2015
"Unfortunately, all we'll get are pretty picture's. Until mainstream quits..."

Just how deluded to you have to be to tell mainstream astronomy where they're wrong when you have the grammar skills of a 10 year old?

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