Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Most eccentric planet ever known flashes astronomers with reflected light

21.03.2016

SF State researcher leads team that spots extrasolar planet 'swinging around its star like it's a comet'

Led by San Francisco State University astronomer Stephen Kane, a team of researchers has spotted an extrasolar planet about 117 light-years from earth that boasts the most eccentric orbit yet seen.


This graphic shows the orbit of the planet HD 20782 relative to the inner planets of our solar system. HD 20782's orbit more closely resembles that of a comet, making it the most eccentric planet ever known.

Credit: Stephen Kane

What's more, Kane and his colleagues were able to detect a signal of reflected light from the planet known as HD 20782 -- a "flash" of starlight bouncing off the eccentric planet's atmosphere as it made its closest orbital approach to its star. The discovery was announced online Feb. 28, 2016 in The Astrophysical Journal.

In this case, "eccentric" doesn't refer to a state of mind, but instead describes how elliptical a planet's orbit is around its star. While the planets in our solar system have nearly circular orbits, astronomers have discovered several extrasolar planets with highly elliptical or eccentric orbits.

HD 20782 has the most eccentric orbit known, measured at an eccentricity of .96. This means that the planet moves in a nearly flattened ellipse, traveling a long path far from its star and then making a fast and furious slingshot around the star at its closest approach.

HD 20782 offers "a particularly lucrative observing opportunity" for studying the planetary atmosphere of an eccentric-orbit planet -- a type not seen in our own solar system, the scientists say in the journal article. By studying the reflected light from HD 20782, astronomers may learn more about the structure and composition of a planetary atmosphere that can withstand a brief but blistering exposure to its star.

At the furthest point in its orbit, the planet is separated from its star by 2.5 times the distance between the sun and Earth. At its closest approach, it ventures as close as .06 of that same Earth-sun distance -- much closer than Mercury orbits the sun, said Kane, an assistant professor of physics and astronomy. "It's around the mass of Jupiter, but it's swinging around its star like it's a comet."

An earlier observation of HD 20782 suggested that the planet might have an extremely eccentric orbit. Kane and his colleagues were able to confirm its extreme eccentricity and the rest of its orbital parameters as part of the Transit Ephemeris Refinement and Monitoring Survey (TERMS), a project led by Kane to detect extrasolar planets as they pass in front of their stars.

Using these new parameters to time their observations, the scientists also used a satellite-based telescope to collect light data from the planet as it orbited closest to its star. They were able to detect a change in brightness that appears to be a signal of reflected light bouncing off the planet's atmosphere.

The reflected light could tell researchers more about how the atmosphere of a planet like HD 20782 responds when it spends most of its time far away from its star, "but then has a very close approach where it's flash-heated by the star," Kane said.

The percentage of light reflected from a planet, or how bright it appears in the sky, is determined in part by the composition of its atmosphere. Planets shrouded in clouds full of icy particles, like Venus and Jupiter, for instance, are very reflective. But if a planet like Jupiter were to move too close to the sun, the heat would remove the icy material in its clouds.

In some of the extrasolar, Jupiter-sized planets that tread short, circular orbits, Kane explained, this phenomenon does appear to strip the atmospheres of reflective particles, making the planets appear "dark." But in the case of HD 20782, "the atmosphere of the planet doesn't have a chance to respond," he said. "The time it takes to swing around the star is so quick that there isn't time to remove all the icy materials that make the atmosphere so reflective."

Astronomers can't determine the exact makeup of HD 20782's atmosphere yet, but this newest observation does suggest that it might have an atmosphere with Jupiter-like, highly reflective cloud cover.

Extrasolar planets like HD 20782 contain a wealth of questions for astronomers, Kane said. "When we see a planet like this that is in an eccentric orbit, it can be really hard to try and explain how it got that way," he explained. "It's kind of like looking at a murder scene, like those people who examine blood spatter patterns on the walls. You know something bad has happened, but you need to figure out what it was that caused it."

There are few possible "suspects" in the case of HD 20782, Kane noted. It could be that there was originally more than one planet in the system, and one planet developed an unstable orbit that brought the two planets too close together. This collision or near-collision might have ejected one planet from the system entirely and pushed HD 20782 on its eccentric path. The planet is in a binary star system, so it might also be the case that the second star in the binary made a close approach that threw HD 20782 off a more circular orbit.

Kane is a member of the science team for two upcoming satellite missions -- NASA's Transiting Exoplanet Survey Satellite (TESS) and the European Space Agency's Characterizing ExOPLanet Satellite (CHEOPS) -- that will have HD 20782 in their sights after they launch in 2018.

###

"Evidence for reflected light from the most eccentric exoplanet known" by Stephen R. Kane, Robert A. Wittenmyer (University of New South Wales), Natalie R. Hinkel (Arizona State University), Arpita Roy and Suvrath Mahadevan (Pennsylvania State University), Diana Dragomir (Las Cumbres Observatory Global Telescope Network), Jaymie M. Matthews (University of British Columbia), Gregory W. Henry (Tennessee State University), Abhijit Chakraborty (Physical Research Laboratory, Navrangpura), Tabetha S. Boyajian (Yale University), Jason T. Wright (Pennsylvania State University), David R. Ciardi (Caltech), Debra A. Fischer (Yale University), R. Paul Butler (Carnegie Institution of Washington), C.G. Tinney (University of New South Wales), Brad D. Carter (University of Southern Queensland), Hugh R.A. Jones (University of Hertfordshire), Jeremy Bailey (University of New South Wales) and Simon J. O'Toole (Australian Astronomical Observatory) was published online on Feb. 28.

San Francisco State University makes things happen. Founded in 1899, it is the only master's-level public university serving the counties of San Francisco, San Mateo and Marin. Its nationally acclaimed programs span a broad range of disciplines. Nearly 30,000 students enroll at the University each year, and its more than 236,000 graduates have contributed to the economic, cultural and civic fabric of San Francisco and beyond. Through them -- and more than 1,600 world-class faculty members -- SF State proudly embraces its legacy of academic excellence, community engagement and commitment to social justice. For more information, visit sfsu.edu

Media Contact

Jonathan Morales
jmm1@sfsu.edu
415-338-1743

 @SFSU

http://www.sfsu.edu 

Jonathan Morales | EurekAlert!

More articles from Physics and Astronomy:

nachricht Light-emitting bubbles captured in the wild
28.02.2017 | Georg-August-Universität Göttingen

nachricht Scientists reach back in time to discover some of the most power-packed galaxies
28.02.2017 | Clemson University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Light-emitting bubbles captured in the wild

28.02.2017 | Physics and Astronomy

Triboelectric nanogenerators boost mass spectrometry performance

28.02.2017 | Materials Sciences

Calculating recharge of groundwater more precisely

28.02.2017 | Ecology, The Environment and Conservation

VideoLinks
B2B-VideoLinks
More VideoLinks >>>