Artist's impression of a gas giant planet forming in the disc around the young star HD 100546
VLT and Hubble images of the protoplanet system HD 100546
PR Image eso1310c
VLT image of the protoplanet around the young star HD 100546
Source: ESO
NASA/ESA Hubble Space Telescope view of the dust disc around the young star HD 100546
The young star HD 100546 in the southern constellation of Musca
Wide-field view of the sky around the young star HD 100546
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Candidate protoplanet spotted inside its stellar womb
Astronomers using ESO’s Very Large
Telescope have obtained what is likely the first direct observation of a
forming planet still embedded in a thick disc of gas and dust. If
confirmed, this discovery will greatly improve our understanding of how
planets form and allow astronomers to test the current theories against
an observable target.
An international team led by Sascha Quanz (ETH Zurich, Switzerland)
has studied the disc of gas and dust that surrounds the young star HD
100546, a relatively nearby neighbour located 335 light-years from
Earth. They were surprised to find what seems to be a planet in the
process of being formed, still embedded in the disc of material around
the young star. The candidate planet would be a gas giant similar to
Jupiter.
“So far, planet formation has mostly been a topic tackled by computer simulations,” says Sascha Quanz. “If our discovery is indeed a forming planet, then for the first time scientists will be able to study the planet formation process and the interaction of a forming planet and its natal environment empirically at a very early stage.”
HD 100546 is a well-studied object, and it has already been suggested that a giant planet orbits about six times further from the star than the Earth is from the Sun. The newly found planet candidate is located in the outer regions of the system, about ten times further out [1].
The planet candidate around HD 100546 was detected as a faint blob located in the circumstellar disc revealed thanks to the NACO adaptive optics instrument on ESO’s VLT, combined with pioneering data analysis techniques. The observations were made using a special coronagraph in NACO, which operates at near-infrared wavelengths and suppresses the brilliant light coming from the star at the location of the protoplanet candidate [2].
According to current theory, giant planets grow by capturing some of the gas and dust that remains after the formation of a star [3]. The astronomers have spotted several features in the new image of the disc around HD100546 that support this protoplanet hypothesis. Structures in the dusty circumstellar disc, which could be caused by interactions between the planet and the disc, were revealed close to the detected protoplanet. Also, there are indications that the surroundings of the protoplanet are potentially heated up by the formation process.
Adam Amara, another member of the team, is enthusiastic about the finding. “Exoplanet research is one of the most exciting new frontiers in astronomy, and direct imaging of planets is still a new field, greatly benefiting from recent improvements in instruments and data analysis methods. In this research we used data analysis techniques developed for cosmological research, showing that cross-fertilisation of ideas between fields can lead to extraordinary progress.”
Although the protoplanet is the most likely explanation for the observations, the results of this study require follow-up observations to confirm the existence of the planet and discard other plausible scenarios. Among other explanations, it is possible, although unlikely, that the detected signal could have come from a background source. It is also possible that the newly detected object might not be a protoplanet, but a fully formed planet which was ejected from its original orbit closer to the star. When the new object around HD 100546 is confirmed to be a forming planet embedded in its parent disc of gas and dust, it will become an unique laboratory in which to study the formation process of a new planetary system.
“So far, planet formation has mostly been a topic tackled by computer simulations,” says Sascha Quanz. “If our discovery is indeed a forming planet, then for the first time scientists will be able to study the planet formation process and the interaction of a forming planet and its natal environment empirically at a very early stage.”
HD 100546 is a well-studied object, and it has already been suggested that a giant planet orbits about six times further from the star than the Earth is from the Sun. The newly found planet candidate is located in the outer regions of the system, about ten times further out [1].
The planet candidate around HD 100546 was detected as a faint blob located in the circumstellar disc revealed thanks to the NACO adaptive optics instrument on ESO’s VLT, combined with pioneering data analysis techniques. The observations were made using a special coronagraph in NACO, which operates at near-infrared wavelengths and suppresses the brilliant light coming from the star at the location of the protoplanet candidate [2].
According to current theory, giant planets grow by capturing some of the gas and dust that remains after the formation of a star [3]. The astronomers have spotted several features in the new image of the disc around HD100546 that support this protoplanet hypothesis. Structures in the dusty circumstellar disc, which could be caused by interactions between the planet and the disc, were revealed close to the detected protoplanet. Also, there are indications that the surroundings of the protoplanet are potentially heated up by the formation process.
Adam Amara, another member of the team, is enthusiastic about the finding. “Exoplanet research is one of the most exciting new frontiers in astronomy, and direct imaging of planets is still a new field, greatly benefiting from recent improvements in instruments and data analysis methods. In this research we used data analysis techniques developed for cosmological research, showing that cross-fertilisation of ideas between fields can lead to extraordinary progress.”
Although the protoplanet is the most likely explanation for the observations, the results of this study require follow-up observations to confirm the existence of the planet and discard other plausible scenarios. Among other explanations, it is possible, although unlikely, that the detected signal could have come from a background source. It is also possible that the newly detected object might not be a protoplanet, but a fully formed planet which was ejected from its original orbit closer to the star. When the new object around HD 100546 is confirmed to be a forming planet embedded in its parent disc of gas and dust, it will become an unique laboratory in which to study the formation process of a new planetary system.
Notes
[1] The protoplanet candidate orbits
about 70 times further from its star than the Earth does from the Sun.
This distance is comparable to the size of the orbits of outer Solar
System dwarf planets such as Eris and Makemake. This location is
controversial, as it does not fit well with current theories of planet
formation. It is unclear at present whether the newfound planet
candidate has been in its current position for the whole time since it
formed or whether it could have migrated from the inner regions.
[2] The team made use of a special feature called an
apodised phase plate that increases the contrast of the image close to
the star.
[3] To study planet formation, astronomers cannot
look at the Solar System, as all the planets in our neighborhood were
formed more than four billion years ago. But for many years, theories
about planet formation were strongly influenced by what astronomers
could see in our local surroundings, as no other planets were known.
Since 1995, when the first exoplanet around a sunlike star was
discovered, several hundred planetary systems have been found, opening
up new opportunities for scientists studying planetary formation. Up to
now however, none have been “caught in the act” in the process of being
formed, whilst still embedded in the disc of material around their young
parent star.
More information
This research was presented in a paper “A
Young Protoplanet Candidate Embedded in the Circumstellar disc of HD
100546”, by S. P. Quanz et al., to appear online in the 28 February 2013
issue of Astrophysical Journal Letters.
The team is composed of Sascha P. Quanz (ETH Zurich, Switzerland),
Adam Amara (ETH), Michael R. Meyer (ETH), Matthew A. Kenworthy
(Sterrewacht Leiden, Netherlands), Markus Kasper (ESO, Garching,
Germany) and Julien H. Girard (ESO, Santiago, Chile).
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
Contacts
Sascha P. Quanz
ETH Zurich
Zurich, Switzerland
Tel: +41 (0) 44 63 32830
Email: sascha.quanz@astro.phys.ethz.ch
ETH Zurich
Zurich, Switzerland
Tel: +41 (0) 44 63 32830
Email: sascha.quanz@astro.phys.ethz.ch
Julien H. Girard
ESO
Santiago, Chile
Tel: +56 2 2463 5342
Email: jgirard@eso.org
ESO
Santiago, Chile
Tel: +56 2 2463 5342
Email: jgirard@eso.org
Richard Hook
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Source: ESO
