February 28, 2013
Astronomers Make First Direct Observation Of A Forming Planet
[WATCH VIDEO: Flying Through The HD 100546 System]
Lee Rannals for redOrbit.com — Your Universe Online
Astronomers, for the first time, may have made a direct observation of a planet forming inside a thick disc of gas and dust.
An international team led by Sascha Quanz, of the Swiss Federal Institute of Technology (ETH Zurich), used the European Space Observatory's (ESO) Very Large Telescope (VLT). Their discovery could help improve scientists' knowledge of how planets form and allow astronomers to test the current theories against an observable target.
“So far, planet formation has mostly been a topic tackled by computer simulations,” said Quanz in a statement. “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 has already been well-studied. Astronomers have previously suggested that a giant planet orbits the star, but about six times farther out than the orbit the Earth has around its own parent star. The new planet candidate is actually about ten times farther out, in the star system´s outer regions, the astronomers have found.
This finding puts the protoplanet in orbit about 70 times farther from its star than Earth exists from the Sun. This distance is comparable to the orbit found with our Solar System´s outer dwarf planets Eris and Makemake.
The planet candidate was detected by the VLT using a special coronagraph operating in near-infrared wavelengths, helping to suppress the light coming from the star at the location of the protoplanet candidate.
According to theories, this protoplanet candidate is growing by capturing some of the gas and dust that remains after the formation of its star. Astronomers spotted several features in the new image of the disc around HD 100546 that supports this protoplanet hypothesis. Structures in this disc were revealed close to the detected protoplanet.
“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-fertilization of ideas between fields can lead to extraordinary progress," said Adam Amara, another member of the team.
Astronomers will need to provide follow-up observations to confirm the existence of the planet, and discard other plausible scenarios. It is possible that the detected signal could have come from a background source, and that the newly detected object might be a protoplanet. Once the protoplanet candidate is confirmed, scientists will be able to use it to study the formation process of a new planetary system.
The distance the protoplanet sits from its sun makes it a bit of a controversial topic among astronomers, because it does not fit well with current theories of planet formation.
Scientists are not only on the hunt for finding planets outside of our solar system, but they are looking specifically for planets that lie in the "habitable zone," which is the proper distance a planet can be from a star for it to contain liquid water.
A new theory suggests that even white dwarfs, which are very cool stars with a core about the size of Earth, may be able to host habitable planets.
“In the quest for extraterrestrial biological signatures, the first stars we study should be white dwarfs,” said Avi Loeb, a researcher at the Harvard-Smithsonian Center for Astrophysics (CfA) and director of the Institute for Theory and Computation (ITC).
Although white dwarfs are on their last leg of life, they can actually retain heat long enough to warm a nearby planet for a billion years, allowing plenty of time for evolution to kick in on a habitable planet. NASA is building its James Webb Space Telescope to help give scientists a special look at exoplanets. This instrument will be a key for unveiling what lies behind our dark sky.