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 Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>