Phosphorus-bearing molecules found in a star-forming region and comet 67P
ALMA view of the star-forming region AFGL 5142
Rosetta view of comet 67P/Churyumov–Gerasimenko
Location of AFGL 5142 in the constellation of Auriga
Wide-field view of the region of the sky where AFGL 5142 is located
Videos
ESOcast 215 Light: Interstellar Thread of One of Life’s Building Blocks Revealed
Zooming into star-forming region AFGL 5142
Animated view of comet 67P/Churyumov–Gerasimenko
Animated view of phosphorus-bearing molecules found in a star-forming region and comet 67P
ALMA and Rosetta map the journey of phosphorus
Phosphorus, present in our DNA and cell
membranes, is an essential element for life as we know it. But how it
arrived on the early Earth is something of a mystery. Astronomers have
now traced the journey of phosphorus from star-forming regions to comets
using the combined powers of ALMA and the European Space Agency’s probe
Rosetta. Their research shows, for the first time, where molecules
containing phosphorus form, how this element is carried in comets, and
how a particular molecule may have played a crucial role in starting
life on our planet.
"Life appeared on Earth about 4 billion years ago, but we still do not know the processes that made it possible," says Víctor Rivilla, the lead author of a new study published today in the journal Monthly Notices of the Royal Astronomical Society. The new results from the Atacama Large Millimeter/Submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner, and from the ROSINA instrument on board Rosetta, show that phosphorus monoxide is a key piece in the origin-of-life puzzle.
With the power of ALMA, which allowed a detailed look into
the star-forming region AFGL 5142, astronomers could pinpoint where
phosphorus-bearing molecules, like phosphorus monoxide, form. New stars
and planetary systems arise in cloud-like regions of gas and dust in
between stars, making these interstellar clouds the ideal places to
start the search for life’s building blocks.
The ALMA observations showed that phosphorus-bearing
molecules are created as massive stars are formed. Flows of gas from
young massive stars open up cavities in interstellar clouds. Molecules
containing phosphorus form on the cavity walls, through the combined
action of shocks and radiation from the infant star. The astronomers
have also shown that phosphorus monoxide is the most abundant
phosphorus-bearing molecule in the cavity walls.
After searching for this molecule in star-forming regions
with ALMA, the European team moved on to a Solar System object: the
now-famous comet 67P/Churyumov–Gerasimenko.
The idea was to follow the trail of these phosphorus-bearing compounds.
If the cavity walls collapse to form a star, particularly a
less-massive one like the Sun, phosphorus monoxide can freeze out and
get trapped in the icy dust grains that remain around the new star. Even
before the star is fully formed, those dust grains come together to
form pebbles, rocks and ultimately comets, which become transporters of
phosphorus monoxide.
ROSINA, which stands for Rosetta Orbiter Spectrometer for
Ion and Neutral Analysis, collected data from 67P for two years as
Rosetta orbited the comet. Astronomers had found hints of phosphorus in
the ROSINA data before, but they did not know what molecule had carried
it there. Kathrin Altwegg, the Principal Investigator for Rosina and an
author in the new study, got a clue about what this molecule could be
after being approached at a conference by an astronomer studying
star-forming regions with ALMA: “She said that phosphorus monoxide would be a very likely candidate, so I went back to our data and there it was!”
This first sighting of phosphorus monoxide on a comet helps
astronomers draw a connection between star-forming regions, where the
molecule is created, all the way to Earth.
“The combination of the ALMA and ROSINA data has
revealed a sort of chemical thread during the whole process of star
formation, in which phosphorus monoxide plays the dominant role,”
says Rivilla, who is a researcher at the Arcetri Astrophysical
Observatory of INAF, Italy’s National Institute for Astrophysics.
“Phosphorus is essential for life as we know it,” adds Altwegg. “As
comets most probably delivered large amounts of organic compounds to
the Earth, the phosphorus monoxide found in comet 67P may strengthen the
link between comets and life on Earth.”
This intriguing journey could be documented because of the collaborative efforts between astronomers. “The
detection of phosphorus monoxide was clearly thanks to an
interdisciplinary exchange between telescopes on Earth and instruments
in space,” says Altwegg.
Leonardo Testi, ESO astronomer and ALMA European Operations Manager, concludes:
“Understanding
our cosmic origins, including how common the chemical conditions
favourable for the emergence of life are, is a major topic of modern
astrophysics. While ESO and ALMA focus on the observations of molecules
in distant young planetary systems, the direct exploration of the
chemical inventory within our Solar System is made possible by ESA
missions, like Rosetta. The synergy between world leading ground-based
and space facilities, through the collaboration between ESO and ESA, is a
powerful asset for European researchers and enables transformational
discoveries like the one reported in this paper.”
More Information
This research was presented in a paper to appear in Monthly Notices of the Royal Astronomical Society.
The team is composed of V. M. Rivilla (INAF-Osservatorio
Astrofisico di Arcetri, Florence, Italy [INAF-OAA]), M. N. Drozdovskaya
(Center for Space and Habitability, University of Bern, Switzerland
[CSH]), K. Altwegg (Physikalisches Institut, University of Bern,
Switzerland), P. Caselli (Max Planck Institute for Extraterrestrial
Physics, Garching, Germany), M. T. Beltrán (INAF-OAA), F. Fontani
(INAF-OAA), F.F.S. van der Tak (SRON Netherlands Institute for Space
Research, and Kapteyn Astronomical Institute, University of Groningen,
The Netherlands), R. Cesaroni (INAF-OAA), A. Vasyunin (Ural Federal
University, Ekaterinburg, Russia, and Ventspils University of Applied
Sciences, Latvia), M. Rubin (CSH), F. Lique (LOMC-UMR, CNRS–Université
du Havre), S. Marinakis (University of East London, and Queen Mary
University of London, UK), L. Testi (INAF-OAA, ESO Garching, and
Excellence Cluster “Universe”, Germany), and the ROSINA team (H.
Balsiger, J. J. Berthelier, J. De Keyser, B. Fiethe, S. A. Fuselier, S.
Gasc, T. I. Gombosi, T. Sémon, C. -y. Tzou).
The Atacama Large Millimeter/submillimeter Array (ALMA), an
international astronomy facility, is a partnership of ESO, the U.S.
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 has 16 Member States: Austria,
Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland,
Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland
and the United Kingdom, along with the host state of Chile and with
Australia as a Strategic Partner. 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 and its
world-leading Very Large Telescope Interferometer as well as two survey
telescopes, VISTA working in the infrared and the visible-light VLT
Survey Telescope. Also at Paranal ESO will host and operate the
Cherenkov Telescope Array South, the world’s largest and most sensitive
gamma-ray observatory. ESO is also a major partner in two facilities on
Chajnantor, APEX and ALMA, the largest astronomical project in
existence. And on Cerro Armazones, close to Paranal, ESO is building the
39-metre Extremely Large Telescope, the ELT, which will become “the
world’s biggest eye on the sky”.
Source: ESO/News
Links
Contacts
Víctor Rivilla
INAF Arcetri Astrophysical Observatory
Florence, Italy
Tel: +39 055 2752 319
Email: rivilla@arcetri.astro.it
Kathrin Altwegg
University of Bern
Bern, Switzerland
Tel: +41 31 631 44 20
Email: kathrin.altwegg@space.unibe.ch
Leonardo Testi
European Southern Observatory
Garching bei München, Germany
Tel: +49 89 3200 6541
Email: ltesti@eso.org
Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: pio@eso.org
