Artist impression of the protoplanetary disc surrounding the young star MWC 480
The sky around the young star MWC 480
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Hints that the building blocks of the chemistry of life are universal
For the first time, astronomers have
detected the presence of complex organic molecules, the building blocks
of life, in a protoplanetary disc surrounding a young star. The
discovery, made with the Atacama Large Millimeter/submillimeter Array
(ALMA), reaffirms that the conditions that spawned the Earth and Sun are
not unique in the Universe. The results are published in the 9 April
2015 issue of the journal Nature.
The new ALMA observations reveal that the protoplanetary disc surrounding the young star MWC 480 [1] contains large amounts of methyl cyanide (CH3CN), a complex carbon-based molecule. There is enough methyl cyanide around MWC 480 to fill all of Earth’s oceans.
Both this molecule and its simpler cousin hydrogen cyanide
(HCN) were found in the cold outer reaches of the star’s newly formed
disc, in a region that astronomers believe is analogous to the Kuiper Belt — the realm of icy planetesimals and comets in our own Solar System beyond Neptune.
Comets retain a pristine record of the early chemistry of the Solar
System, from the period of planet formation. Comets and asteroids from
the outer Solar System are thought to have seeded the young Earth with
water and organic molecules, helping set the stage for the development
of primordial life.
“Studies of comets and asteroids show that the solar nebula that
spawned the Sun and planets was rich in water and complex organic
compounds,” noted Karin Öberg, an astronomer with the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts,
USA, and lead author of the new paper.
“We now have even better evidence that this same chemistry exists
elsewhere in the Universe, in regions that could form solar systems not
unlike our own.” This is particularly intriguing, Öberg notes,
since the molecules found in MWC 480 are also found in similar
concentrations in the Solar System’s comets.
The star MWC 480, which is about twice the mass of the Sun, is
located 455 light-years away in the Taurus star-forming region. Its
surrounding disc is in the very early stages of development — having
recently coalesced out of a cold, dark nebula of dust and gas. Studies
with ALMA and other telescopes have yet to detect any obvious signs of
planet formation in it, although higher resolution observations may
reveal structures similar to HL Tauri, which is of a similar age.
Astronomers have known for some time that cold, dark interstellar
clouds are very efficient factories for complex organic molecules —
including a group of molecules known as cyanides. Cyanides, and most
especially methyl cyanide, are important because they contain
carbon–nitrogen bonds, which are essential for the formation of amino
acids, the foundation of proteins and the building blocks of life.
Until now, it has remained unclear, however, if these same complex
organic molecules commonly form and survive in the energetic environment
of a newly forming solar system, where shocks and radiation can easily
break chemical bonds.
By exploiting ALMA’s remarkable sensitivity [2] astronomers can see from the latest observations that these molecules not only survive, but flourish.
Importantly, the molecules ALMA detected are much more abundant than
would be found in interstellar clouds. This tells astronomers that
protoplanetary discs are very efficient at forming complex organic
molecules and that they are able to form them on relatively short
timescales [3].
As this system continues to evolve, astronomers speculate that it’s
likely that the organic molecules safely locked away in comets and other
icy bodies will be ferried to environments more nurturing to life.
“From the study of exoplanets, we know the Solar System isn’t unique in its number of planets or abundance of water,” concluded Öberg. “Now
we know we’re not unique in organic chemistry. Once more, we have
learnt that we’re not special. From a life in the Universe point of
view, this is great news.”
Notes
[1] This star is only about one million years old. By comparison the Sun is more than four billion years old. The name MWC 480 refers to the Mount Wilson Catalog of B and A stars with bright hydrogen lines in their spectra.
[2] ALMA is able to detect the faint millimetre-wavelength radiation that is naturally emitted by molecules in space. For these most recent observations, the astronomers used only a portion of ALMA’s 66 antennas when the telescope was in its lower-resolution configuration. Further studies of this and other protoplanetary discs with ALMA’s full capabilities will reveal additional details about the chemical and structural evolution of stars and planets.
[3] This rapid formation is essential to outpace the forces that would otherwise break the molecules apart. Also, these molecules were detected in a relatively serene part of the disc, roughly 4.5 to 15 billion kilometres from the central star. Though very distant by Solar System standards, in MWC 480’s scaled-up dimensions, this would be squarely in the comet-forming zone.
More Information
This research was presented in a paper entitled “The Cometary Composition of a Protoplanetary Disk as Revealed by Complex Cyanides” by K.I. Öberg et al., to appear in the journal Nature on 9 April 2015.
The team is composed of Karin I. Öberg (Harvard-Smithsonian Centre for Astrophysics, Cambridge, Massachusetts, USA), Viviana V. Guzmán (Harvard-Smithsonian Centre for Astrophysics), Kenji Furuya (Leiden Observatory, Leiden University, Leiden, the Netherlands), Chunhua Qi (Harvard-Smithsonian Centre for Astrophysics), Yuri Aikawa (Kobe University, Kobe, Japan), Sean M. Andrews (Harvard-Smithsonian Centre for Astrophysics), Ryan Loomis (Harvard-Smithsonian Centre for Astrophysics) and David J. Wilner (Harvard-Smithsonian Centre for Astrophysics).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the US National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. 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 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. 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 a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
Links
Contact :
Karin Öberg
Harvard-Smithsonian Centre for Astrophysics
Cambridge MA, USA
Cell: +1 617 496 9062
Email: koberg@cfa.harvard.edu
Richard Hook
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Notes
[1] This star is only about one million years old. By comparison the Sun is more than four billion years old. The name MWC 480 refers to the Mount Wilson Catalog of B and A stars with bright hydrogen lines in their spectra.
[2] ALMA is able to detect the faint millimetre-wavelength radiation that is naturally emitted by molecules in space. For these most recent observations, the astronomers used only a portion of ALMA’s 66 antennas when the telescope was in its lower-resolution configuration. Further studies of this and other protoplanetary discs with ALMA’s full capabilities will reveal additional details about the chemical and structural evolution of stars and planets.
[3] This rapid formation is essential to outpace the forces that would otherwise break the molecules apart. Also, these molecules were detected in a relatively serene part of the disc, roughly 4.5 to 15 billion kilometres from the central star. Though very distant by Solar System standards, in MWC 480’s scaled-up dimensions, this would be squarely in the comet-forming zone.
More Information
This research was presented in a paper entitled “The Cometary Composition of a Protoplanetary Disk as Revealed by Complex Cyanides” by K.I. Öberg et al., to appear in the journal Nature on 9 April 2015.
The team is composed of Karin I. Öberg (Harvard-Smithsonian Centre for Astrophysics, Cambridge, Massachusetts, USA), Viviana V. Guzmán (Harvard-Smithsonian Centre for Astrophysics), Kenji Furuya (Leiden Observatory, Leiden University, Leiden, the Netherlands), Chunhua Qi (Harvard-Smithsonian Centre for Astrophysics), Yuri Aikawa (Kobe University, Kobe, Japan), Sean M. Andrews (Harvard-Smithsonian Centre for Astrophysics), Ryan Loomis (Harvard-Smithsonian Centre for Astrophysics) and David J. Wilner (Harvard-Smithsonian Centre for Astrophysics).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the US National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. 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 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. 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 a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
Links
Contact :
Karin Öberg
Harvard-Smithsonian Centre for Astrophysics
Cambridge MA, USA
Cell: +1 617 496 9062
Email: koberg@cfa.harvard.edu
Richard Hook
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Source: ESO
