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
For the first time astronomers have caught a multiple-star system as it
is created, and their observations are providing new insight into how
such systems, and possibly the solar system, are formed.
Amazing images taken from a series of telescopes on Earth show clouds of gas which are in the process of developing into stars.
Scientists from The University of Manchester, Liverpool John Moores
University and other institutes in Europe and around the world, looked
at a cloud of gas some 800 light-years from Earth, homing in on a core
of gas that contains one young protostar and three dense pockets of
matter that they say will collapse into stars over the next 40,000
years. Of the eventual four stars, the astronomers predict that three
may become a stable triple-star system. The findings are published today
in the journal Nature.
“These kind of multi-star systems
are quite common in the Universe. Think of Tatooine in Star Wars, where
there are two ‘suns’ in the sky, that isn’t too far away from
something that could be a real formation. In fact nearly half of all
stars are in this type of system,” said Professor Gary Fuller, of the
Jodrell Bank Centre for Astrophysics, The University of Manchester.
“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.”
Dr Richard Parker, of the Astrophysics
Research Institute at LJMU who performed the stability analysis
calculations on the system, said: “Observing the formation and
subsequent destruction of these systems will ultimately help us to
understand whether our own Sun was once part of such a system and if it
was, what happened to its stellar siblings.”
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 used the VLA to map radio emission from ammonia molecules, they
discovered that filaments of gas in B5 are fragmenting, and the
fragments are beginning to contract to form additional stars
ultimately becoming a multiple-star system.
Jaime Pineda, of the
Institute for Astronomy, ETH Zurich, in Switzerland, who led the
project, said: “We know that these stars eventually will form a
multi-star system because our observations show that these gas
condensations are gravitationally bound. This is the first time we've been able to show that such a young system is gravitationally bound.”
“This
provides fantastic evidence that fragmentation of gas filaments is a
process that can produce multiple-star systems," Dr 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," Dr 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.
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. The other two stars, they suggest, will be ejected from
the system.
Notes for Editors
Ref. 'The formation of a quadruple star system with wide separation ' has been scheduled for publication in Nature on 12 February 2015.
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