Taking advantage of the unprecedented sensitivity of the Large Binocular Telescope in southeastern Arizona, an international team of astronomers has obtained the first results from the LEECH exoplanets survey
Astronomers have probed deeper than before into a planetary system 130 light-years from Earth. The observations mark the first results of a new exoplanet survey called LEECH (LBT Exozodi Exoplanet Common Hunt), and are published today in the journal Astronomy and Astrophysics.
The planetary system of HR8799, a young star only 30 million years old, was the first to be directly imaged, with three planets found in in 2008 and a fourth one in 2010.
"This star was therefore a target of choice for the LEECH survey, offering the opportunity to acquire new images and better define the dynamical properties of the exoplanets orbiting," said Christian Veillet, director of the Large Binocular Telescope Observatory (LBTO).
The LEECH survey began at the Large Binocular Telescope (LBT) in southeastern Arizona in February 2013 to search for and characterize young and adolescent exoplanets in the near-infrared spectrum (specifically, at a wavelength of 3.8 micrometers that astronomers call the L' band). LEECH exploits the superb performance of the LBT adaptive optics system to image exoplanets with the L/M-band infrared camera (LMIRCam) installed in the LBT Interferometer (LBTI).
"The LBT enables us to look at those planets at a wavelength that nobody else is really using," Veillet explained. "Because they are gas giants and still very young, they glow nicely at the L' band, and because they appear so bright there, they stand out, allowing us to observe closer to the star. This has allowed us to nail down the orbits of this system, which is pretty far away."
"Normally the problem with this approach would be that at 4 microns, telescope optics glow themselves," said Andy Skemer, a Hubble Fellow at the University of Arizona's Department of Astronomy and Steward Observatory and the lead of the survey. "However, with LBT, everything about the telescope, its adaptive optics system and science camera have been optimized to minimize this glow. As a result, LEECH is more sensitive than previous exoplanet imaging surveys, and this new image of HR 8799 is proof."
The study was dedicated to studying the planet architecture of the HR 8799 system, according to the leading author, Anne-Lise Maire, a postdoctoral fellow at INAF-Padova Observatory in Padova, Italy. The team sought to constrain the orbital parameters of the four known giant planets and the physical properties of a putative fifth planet inside the known planets.
"To address the first point, we investigated in particular the types of resonances between the planet orbits," Maire explained. "From the resonances, we learn not only about the overall architecture of the planetary system, but also about the mass range of the planets."
"They cannot be too massive, or else the system would be dynamically unstable, as previous studies have suggested. Moreover, the presence of resonances between the planets indicates that they gravitationally interact with each other, which gives us a lower limit on their masses."
The results of this study favor an architecture for the system based on multiple double resonances, in other words, each of the three outer planets takes about twice as long to complete an orbit around the star as its neighbor closer to the star.
"LEECH's unique sensitivity enabled us to probe the inner region of this planetary system," added Wolfgang Brandner, a scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany. "A fifth massive giant planet in an inner resonant orbit was excluded. This could mean that the HR 8799 planetary system has an architecture similar to the solar system, with four massive planets at larger distances, and potentially lower mass planets - which haven't been detected, yet - in the inner planetary system."
"Our observations give us good idea that this system is pretty stable," Veillet added, "in other words, there is no indication those planets are going to collide with each other in a few million years."
In its current configuration, the inner planet LEECH can see approaches the star to about 15 Astronomical Units (AU), Veillet explained, or fifteen times the average distance between the earth and our sun.
"If there were planets of similar brightness closer to the star, we should see it as close as 10 AU," he said, "which corresponds to the orbit of Saturn."
According to Veillet, the LEECH survey is an exemplary project in two ways.
"It takes full advantage of the adaptive optics performance offered by our adaptive secondary mirrors, and it combines resources from most of the LBTO partners - four U.S. universities, two institutes in Germany, and the Italian community - to build a large program of more than 100 observing nights. This would not be possible for a single partner on a reasonable time scale."
The LBT is an international collaboration among institutions in the U.S., Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota and University of Virginia. The Large Binocular Telescope Interferometer is funded by NASA as part of its Exoplanet Exploration program. LMIRCam is funded by the National Science Foundation through grant NSF AST-0705296.
Daniel Stolte | EurekAlert!
A new twist on a mesmerizing story
17.01.2019 | ETH Zurich Department of Physics
Ultra ultrasound to transform new tech
17.01.2019 | Swansea University
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
Just in time for Christmas, a Mars-analogue mission in Morocco, coordinated by the Robotics Innovation Center of the German Research Center for Artificial Intelligence (DFKI) as part of the SRC project FACILITATORS, has been successfully completed. SRC, the Strategic Research Cluster on Space Robotics Technologies, is a program of the European Union to support research and development in space technologies. From mid-November to mid-December 2018, a team of more than 30 scientists from 11 countries tested technologies for future exploration of Mars and Moon in the desert of the Maghreb state.
Close to the border with Algeria, the Erfoud region in Morocco – known to tourists for its impressive sand dunes – offered ideal conditions for the four-week...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
17.01.2019 | Physics and Astronomy
17.01.2019 | Materials Sciences
17.01.2019 | Information Technology