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Hot Jupiter-like planet: Discovery of two close-in planet companions sheds new light on planet formation

Date:
October 16, 2015
Source:
University of Michigan
Summary:
For the past 20 years, astronomers peered into the night sky, puzzled about a type of planet called hot Jupiters.
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The basic chemistry for life has been detected in a second hot gas planet, HD 209458b, depicted in this artist's concept. Two of NASA's Great Observatories - the Hubble Space Telescope and Spitzer Space Telescope, yielded spectral observations that revealed molecules of carbon dioxide, methane and water vapor in the planet's atmosphere. HD 209458b, bigger than Jupiter, occupies a tight, 3.5-day orbit around a sun-like star about 150 light years away in the constellation Pegasus. Planets like this one, which circle stars beyond our sun, are called exoplanets. The new finding follows the detection of these same organic molecules in the atmosphere of another hot, giant planet, called HD 189733b, by astronomers using Hubble and Spitzer data. Astronomers can now begin comparing the chemistry and dynamics of these two planets, and search for similar measurements of other candidate exoplanets, advancing toward the goal of being able to characterize planets where life could exist. Neither of the two planets studied is habitable, but they display the same molecules that, if found around a rocky planet in the future, could potentially indicate the presence of life. The new findings pave the way for future work that will help astronomers shortlist any promising rocky Earth-like planets where the signatures of organic chemicals might indicate the presence of life.
Credit: NASA/JPL-Caltech/T. Pyle (SSC)

For the past 20 years, astronomers peered into the night sky, puzzled about a type of planet called hot Jupiters.

As they analyzed data from giant telescopes on mountaintops, and later data beamed to Earth from spacecraft such as the Kepler space telescope, they wondered: How did these large hot planets ever get so close to their suns?

Scientists at the University of Michigan, working with a team of colleagues, have made a startling discovery using data collected by the K2 mission: One of these mysterious hot Jupiter systems has not one, but two close-in planetary companions, leading to new clues about planet formation and migration.

"This is really exciting," said Juliette Becker, a graduate student at U-M's Astronomy Department in the College of Literature, Science, and the Arts, and the lead author of a paper highlighting the discovery. "People have looked for these planets and have looked in data that exists for hot Jupiters for years and nothing has come up. So people took it to mean that it was not possible to have these close-in planet companions."

Until now. Some 300 hot Jupiters have been identified over the past two decades, and this is the first time any close-in planets were discovered.

This new discovery is helpful to scientists who are trying to understand how planets form and move in solar systems.

"The whole theory of planet formation and migration is not totally understood," Becker said. "Even today there is a lot of active work being done to figure out how Jupiter got where it was. So anything we can discover on how hot Jupiters migrate is useful in understanding planet formation and migration as a whole."

Hot Jupiters get their name because of their large size and gaseous composition (like Jupiter) and their unusually close location to their sun (hot). Large gaseous planets are believed to be formed in frigid temperatures. In our solar system that means formation must occur beyond the asteroid belt, far from the burning heat of the sun.

Yet mysteriously these hot Jupiters in faraway solar systems orbit at distances roughly 10 to 20 times the radius of the sun away from their stars -- which is significantly closer than Mercury orbits our sun. This leaves astronomers puzzled with just how these hot giants got there.

Hot Jupiters are invisible to the naked eye. There are some super telescopes on earth which pick them up indirectly. Scientists also study data collected from telescopes on space crafts.

Becker and her colleagues made their discovery using data collected from the K-2 mission, which comes from a spacecraft holding the Kepler space telescope. The person who first spotted the possibility of a planet companion in the WASP-47 system was Hans Schwengeler, a "citizen scientist," who made note of it in a public forum called Planet Hunters.

Becker's colleague, Andrew Vanderburg, a graduate student at Harvard University, noted Schwengeler's comments on Planet Hunters and shared it with Becker. The team, which also consists of Fred Adams, a U-M physics professor and Becker's adviser, and Saul Rappaport, a professor at MIT, then ran a comprehensive analysis of the light curve in the K-2 data where this was noted, and confirmed the existence of two close-in planets -- one Neptune sized, and another a super-Earth inner companion.


Story Source:

Materials provided by University of Michigan. Original written by Wendy Wendland Bowyer. Note: Content may be edited for style and length.


Journal Reference:

  1. Juliette C. Becker, Andrew Vanderburg, Fred C. Adams, Saul A. Rappaport, Hans Martin Schwengeler. WASP-47: A HOT JUPITER SYSTEM WITH TWO ADDITIONAL PLANETS DISCOVERED BY K2. The Astrophysical Journal, 2015; 812 (2): L18 DOI: 10.1088/2041-8205/812/2/L18

Cite This Page:

University of Michigan. "Hot Jupiter-like planet: Discovery of two close-in planet companions sheds new light on planet formation." ScienceDaily. ScienceDaily, 16 October 2015. <www.sciencedaily.com/releases/2015/10/151016115817.htm>.
University of Michigan. (2015, October 16). Hot Jupiter-like planet: Discovery of two close-in planet companions sheds new light on planet formation. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/10/151016115817.htm
University of Michigan. "Hot Jupiter-like planet: Discovery of two close-in planet companions sheds new light on planet formation." ScienceDaily. www.sciencedaily.com/releases/2015/10/151016115817.htm (accessed May 23, 2017).

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