ALMA image of the protoplanetary disc around HL Tauri
ALMA/Hubble composite image of the region around the young star HL Tauri
ALMA image of the young star HL Tauri (annotated)
Hubble image of the surroundings of the young star HL Tauri
Comparison of HL Tauri with the Solar System
Artist’s impression of a young star surrounded by a protoplanetary disc
Wide-field view of the sky around the young star HL Tauri
HL Tauri in the constellation of Taurus
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Videos
This new image from ALMA, the Atacama
Large Millimeter/submillimeter Array, reveals extraordinarily fine
detail that has never been seen before in the planet-forming disc around
a young star. These are the first observations that have used ALMA in
its near-final configuration and the sharpest pictures ever made at
submillimetre wavelengths. The new results are an enormous step forward
in the observation of how protoplanetary discs develop and how planets
form.
For ALMA’s first observations in its new and most powerful mode, researchers pointed the antennas at HL Tauri — a young star, about 450 light-years away, which is surrounded by a dusty disc [1].
The resulting image exceeds all expectations and reveals unexpectedly
fine detail in the disc of material left over from star birth. It shows a
series of concentric bright rings, separated by gaps [2].
"These features are almost certainly the result of young
planet-like bodies that are being formed in the disc. This is
surprising since such young stars are not expected to have large
planetary bodies capable of producing the structures we see in this
image," said Stuartt Corder, ALMA Deputy Director.
“When we first saw this image we were astounded at the
spectacular level of detail. HL Tauri is no more than a million years
old, yet already its disc appears to be full of forming planets. This
one image alone will revolutionise theories of planet formation,” explained Catherine Vlahakis, ALMA Deputy Program Scientist and Lead Program Scientist for the ALMA Long Baseline Campaign.
HL Tauri’s disc appears much more developed than would be expected
from the age of the system. Thus, the ALMA image also suggests that the
planet-formation process may be faster than previously thought.
Such high resolution can only be achieved with the long baseline
capabilities of ALMA and provides astronomers with new information that
is impossible to collect with any other facility, even the NASA/ESA
Hubble Space Telescope. “The logistics and infrastructure required
to place antennas at such distant locations required an unprecedented
coordinated effort by an expert international team of engineers and
scientists,” said ALMA Director, Pierre Cox. “These long
baselines fulfill one of ALMA’s major objectives and mark an impressive
technological, scientific and engineering milestone.”
Young stars like HL Tauri are born in clouds of gas and fine dust, in
regions which have collapsed under the effects of gravitation, forming
dense hot cores that eventually ignite to become young stars. These
young stars are initially cocooned in the remaining gas and dust, which
eventually settles into a disc, known as a protoplanetary disc.
Through many collisions the dust particles will stick together,
growing into clumps the size of sand grains and pebbles. Ultimately,
asteroids, comets and even planets can form in the disc. Young planets
will disrupt the disc and create rings, gaps and holes such as those
seen in the structures now observed by ALMA [3].
The investigation of these protoplanetary discs is essential to our
understanding of how Earth formed in the Solar System. Observing the
first stages of planet formation around HL Tauri may show us how our own
planetary system may have looked more than four billion years ago, when
it formed.
“Most of what we know about planet formation today is based on
theory. Images with this level of detail have up to now been relegated
to computer simulations or artist’s impressions. This high resolution
image of HL Tauri demonstrates what ALMA can achieve when it operates in
its largest configuration and starts a new era in our exploration of
the formation of stars and planets,” says Tim de Zeeuw, Director General
of ESO.
Notes
[1] Since September 2014
ALMA has been observing the Universe using its longest ever baselines,
with antennas separated by up to 15 kilometres. This Long Baseline
Campaign will continue until 1 December 2014. The baseline is the
distance between two of the antennas in the array. As a comparison,
other facilities operating at millimetre wavelengths provide antennas
separated by no more than two kilometres. The maximum possible ALMA
baseline is 16 kilometres. Future observations at shorter wavelengths
will achieve even higher image sharpness.
[2] The structures are seen with a
resolution of just five times the distance from the Sun to the Earth.
This corresponds to an angular resolution of about 35 milliarcseconds —
better than what is routinely achieved with the NASA/ESA Hubble Space
Telescope.
[3] In visible light, HL Tauri is
hidden behind a massive envelope of dust and gas. ALMA observes at much
longer wavelengths, which allows it to study the processes right at the
core of this cloud.
More Information:
The Atacama Large Millimeter/submillimeter
Array (ALMA), an international astronomy facility, is a partnership of
Europe, North America and East Asia in cooperation with the Republic of
Chile. ALMA is funded in Europe by the European Southern Observatory
(ESO), in North America by the U.S. National Science Foundation (NSF) in
cooperation with the National Research Council of Canada (NRC) and the
National Science Council of Taiwan (NSC) and in East Asia by the
National Institutes of Natural Sciences (NINS) of Japan in cooperation
with the Academia Sinica (AS) in Taiwan. ALMA construction and
operations are led on behalf of Europe by ESO, on behalf of North
America by the National Radio Astronomy Observatory (NRAO), which is
managed by Associated Universities, Inc. (AUI) and on behalf of East
Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint
ALMA Observatory (JAO) provides the unified leadership and management
of the construction, commissioning and operation of ALMA.
ESO is the foremost intergovernmental astronomy organisation in
Europe and the world’s most productive ground-based astronomical
observatory by far. It is supported by 15 countries: Austria, Belgium,
Brazil, 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 Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO
operates the Very Large Telescope, the world’s most advanced
visible-light astronomical observatory and two survey telescopes. VISTA
works in the infrared and is the world’s largest survey telescope and
the VLT Survey Telescope is the largest telescope designed to
exclusively survey the skies in visible light. ESO is the European
partner of a revolutionary astronomical telescope ALMA, the largest
astronomical project in existence. ESO is currently planning the
39-metre European Extremely Large optical/near-infrared Telescope, the
E-ELT, which will become “the world’s biggest eye on the sky”.
Links
- More about ALMA
- Photos of ALMA
- Videos of ALMA
- ALMA brochure
- The movie ALMA — In Search of our Cosmic Origins
- The ALMA Photo Book In Search of our Cosmic Origins – The Construction of the Atacama Large Millimeter/submillimeter Array
- More press releases based on ALMA data
- Catalog of Circumstellar Discs
Contacts:
Catherine Vlahakis
Joint ALMA Observatory
Santiago, Chile
Tel: +56 9 75515736
Email: cvlahaki@alma.cl
Valeria Foncea Rubens
Joint ALMA Observatory
Santiago, Chile
Tel: +56 2 24676258
Email: vfoncea@alma.cl
Richard Hook
ESO education and Public Outreach Department
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
