Alien solar system Kepler-80 has tightly spaced planets in synchronized orbits

Posted: August 13, 2016 by oldbrew in Astrophysics, exploration, Measurement
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Synchronized orbits of the Kepler-80 system [Credit: Florida Institute of Technology]

Synchronized orbits of the Kepler-80 system [Credit: Florida Institute of Technology]

Another example of planetary resonance has been discovered thanks to NASA’s Kepler space telescope.

Located about 1,100 light years away, Kepler-80, named for the NASA telescope that discovered it, features five small planets orbiting in extreme proximity to their star.

As early as 2012, Kepler scientists found that all five planets orbit in an area about 150 times smaller than the Earth’s orbit around the Sun, with “years” of about one, three, four, seven and nine days.

The planets’ close proximity to each other and their star allowed the Kepler Space Telescope to detect tiny variations (about 0.001 percent) in the length of their “years” due to their mutual gravitational interactions. Analysis revealed that the outer four planets had masses about four- to six-times that of Earth, though they shared Earth’s rocky composition.

All four planets have masses similar to one another, though the two outermost planets are almost twice as big. This was attributed to a very puffy hydrogen/helium atmosphere. These properties are not uncommon for exoplanets, but having precise compositional estimates for multiple planets in the same planetary system is rare.

Another rare attribute of the Kepler-80 system is that its planets have “synchronized” orbits. “The outer four planets return to almost exactly the same configuration every 27 days,” said a researcher. This effect is known as a “resonance” and helps the system remain gravitationally stable.

The study also explained the origin of the synchronized orbits in general – and possibly the tightly-spaced configuration. In a process called migration, the orbits of these planets shrank over time while they were forming. Simulations clearly showed that this migration effect caused the planets to lock into synchronized orbits just like those seen with Kepler-80.

Kepler has discovered hundreds of other STIPs [Systems with Tightly-spaced Inner Planets], which consist of three to seven relatively small and closely packed planets that complete orbits in 1 to 100 days. This new form of planetary system, quite different from our own solar system, is changing the way scientists think about how planets form, including the Earth.

With all the knowledge gained by the analysis of Kepler-80, this system is granting important insight into how STIPs formed.

Full report: Alien solar system boasts tightly spaced planets, unusual orbits | PHYS.ORG

  1. E.M.Smith says:

    It is worth noting that fast orbiting large planets are much easier to find, and found much faster. The sampling will be strongly biased to tight orbit systems for a few hundred years… (If a planet takes 100 years to orbit, you need at least that long to detect transits, wobble, dimming cycles, etc. and then another cycle to confirm…)

  2. oldbrew says:

    Good point EM. Most of the known exoplanet orbit periods so far have more in common with Jupiter’s moons than with the solar system planets.

  3. oldbrew says:

    Another five-planet system with the first two planets near a 2:1 resonance [57:28 ratio works well].

    The orbit periods for the other three planets are estimates only.

    In the Kepler-80 system at least 3 out of the 5 planets have almost the same mass (one has unknown mass).

  4. oldbrew says:

    HR 8799 is an interesting one. The outermost planet has an orbit period of ~450 years.

    ‘The system is more likely to be stable if the planets “e”, “d” and “c” are in a 4:2:1 resonance, which would imply that the orbit of the planet d has an eccentricity exceeding 0.04 in order to match the observational constraints.’

    ‘If confirmed, the HR 8799 planetary system would be the second extrasolar system to be observed with multiple resonances. The 4 planets are still glowing red hot due to their young age and are larger than Jupiter and over time they will cool and shrink to the size of 0.8 to 1.0 Jupiter radii.’


  5. oldbrew says:

    More news on HR 8799: ‘The star HR8799 is so far the only star around which direct imaging has found multiple planets.’

    Resolving the planetesimal belt around HR8799
    August 15, 2016

    ‘CfA astronomer Denis Barkats has joined a team of colleagues to use the giant ALMA submillimeter array to image the disk around HR8799 with a spatial scale as small as only thirty-two au, enough to probe the inner zones of the disk. The team has determined that the inner edge of the planetesimal belt actually starts at around 145 au, and that the belt extends out to 430 au.’

    Solar system comparison: Neptune is at about 30 AU from the Sun, Earth at 1 AU.

  6. You may like to post here this video about how the earth and moon was created NOT TO BE BORING, like this kepler-80.

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