Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Jupiter-like world so hot it stretches definition of 'planet'

06.06.2017

Newly discovered KELT-9b exoplanet is hotter than most stars

A newly discovered Jupiter-like world is so hot that it's stretching the definition of the word "planet."


This is an artist's rendering of KELT-9b and KELT-9. KELT-9b is a gas giant 2.8 times more massive than Jupiter but only half as dense. KELT-9b orbits a star, KELT-9, which is more than twice as large and nearly twice as hot as our sun.

Credit: NASA/JPL-Caltech/R. Hurt (IPAC)

With a day-side temperature of 4,600 Kelvin (more than 7,800 degrees Fahrenheit), planet KELT-9b is hotter than most stars, and only 1,200 Kelvin (about 2,000 degrees Fahrenheit) cooler than our own sun.

In an article in this week's issue of Nature, an international research team led by astronomers at Ohio State University and Vanderbilt University describes a planet with some very unusual features. The article is titled "A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host."

Two Lehigh University astronomers -- Joshua Pepper , assistant professor of physics, and doctoral candidate Jonathan Labadie-Bartz--coauthored the study, which was also presented at the spring meeting of the American Astronomical Society.

KELT-9b is a gas giant 2.8 times more massive than Jupiter but only half as dense, because extreme radiation from its host star has caused its atmosphere to puff up like a balloon. And because it is tidally locked to its star -- as the moon is to Earth -- the day side of the planet is perpetually bombarded by stellar radiation, and as a result is so hot that molecules such as water, carbon dioxide and methane can't form there. The properties of the night side are still mysterious -- molecules may be able to form there, but probably only temporarily.

"It's a planet by any of the typical definitions based on mass, but its atmosphere is almost certainly unlike any other planet we've ever seen just because of the temperature of its day side," said Scott Gaudi, professor of astronomy at Ohio State University and a leader of the study.

KELT-9b orbits a star, dubbed KELT-9, which is more than twice as large and nearly twice as hot as our sun.

"KELT-9 radiates so much ultraviolet radiation that it may completely evaporate the planet," said Keivan Stassun, a professor of physics and astronomy at Vanderbilt who directed the study with Gaudi. "Or, if gas giant planets like KELT-9b possess solid rocky cores as some theories suggest, the planet may be boiled down to a barren rock, like Mercury."

That is, if the star doesn't grow to engulf it first. "KELT-9 will swell to become a red giant star in about a billion years," said Stassun. "The long-term prospects for life, or real estate for that matter, on KELT-9b are not looking good."

A possible UV-fueled tail

Given that its atmosphere is constantly blasted with high levels of ultraviolet radiation, the planet may even be shedding a tail of evaporated planetary material like a comet, Gaudi added.

While Gaudi and Stassun spend a lot of time developing missions designed to find habitable planets in other solar systems, the scientists said there's a good reason to study worlds that are unlivable in the extreme.

"As has been highlighted by the recent discoveries from the MEarth collaboration, the planet around Proxima Centauri, and the astonishing system discovered around TRAPPIST-1, the astronomical community is clearly focused on finding Earthlike planets around small, cooler stars like our sun," said Gaudi. "They are easy targets and there's a lot that can be learned about potentially habitable planets orbiting very low-mass stars in general.

"On the other hand, because KELT-9b's host star is bigger and hotter than the sun, it complements those efforts and provides a kind of touchstone for understanding how planetary systems form around hot, massive stars," Gaudi said.

Stassun added, "As we seek to develop a complete picture of the variety of other worlds out there, it's important to know not only how planets form and evolve, but also when and under what conditions they are destroyed."

A tiny dip in stellar brightness

How was the new planet found?

In 2014, astronomers using the KELT-North telescope at Winer Observatory in Arizona noticed a tiny drop in the star's brightness--about half of one percent-- that indicated that a planet may have passed in front of the star. The brightness dipped once every 1.5 days, which means the planet completes a "yearly" circuit around its star every 1.5 days.

Subsequent observations confirmed the signal to be due to a planet, and revealed it to be what astronomers call a "hot Jupiter"--the ideal kind of planet for the KELT telescopes to spot.

KELT is short for "Kilodegree Extremely Little Telescope." Astronomers at Ohio State, Vanderbilt and Lehigh University jointly operate two KELTs (one each in the Northern and Southern Hemispheres) in order to fill a large gap in the available technologies for finding extrasolar planets.

Other telescopes are designed to look at very faint stars in much small sections of the sky, and at very high resolution. The KELTs, in contrast, look at millions of very bright stars at once, over broad sections of sky, and at low resolution.

It's a low-cost means of planet hunting, using mostly off-the-shelf technology: while a traditional astronomical telescope costs millions of dollars to build, the hardware for a KELT telescope runs less than $75,000.

"This discovery is a testament to the discovery power of small telescopes, and the ability of citizen scientists to directly contribute to cutting-edge scientific research," said Pepper, who built the two KELT telescopes.

The astronomers hope to take a closer look at KELT-9b with other telescopes--including Spitzer, the Hubble Space Telescope (HST), and eventually the James Webb Space Telescope. Observations with HST would enable them to see if the planet really does have a cometary tail, and to determine how much longer that planet will survive its current hellish condition.

###

Besides Vanderbilt, Ohio State and Lehigh, American partner institutions include Fisk University, Pennsylvania State University, the Harvard-Smithsonian Center for Astrophysics, Las Cumbres Observatory Global Telescope Network, University of Notre Dame, NASA Ames Research Center, Bay Area Environmental Research Institute, Swarthmore College, IPAC, Brigham Young University, University of California-Santa Cruz, University of Wyoming, Louisiana State University, University of Louisville, Spot Observatory in Nashville, Westminster College, Kutztown University, University of Hawaii, University of Washington, Texas A&M University, Wellesley College, and the Winer Observatory in Sonoita, Arizona. International team members are from Denmark, Italy, Japan, Portugal, Switzerland, Australia, Germany and South Africa.

The study was largely funded by the National Science Foundation through an NSF CAREER Grant, NSF PAARE Grant and an NSF Graduate Research Fellowship. Additional support came from NASA via the Jet Propulsion Laboratory and the Exoplanet Exploration Program; the Harvard Future Faculty Leaders Postdoctoral Fellowship; Theodore Dunham, Jr., Grant from the Fund for Astronomical Research; and the Japan Society for the Promotion of Science.

Media Contact

Amy White
abw210@lehigh.edu
610-758-6656

 @lehighu

http://www.lehigh.edu 

Amy White | EurekAlert!

More articles from Physics and Astronomy:

nachricht Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen

nachricht New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences

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: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>