NASA’s TESS Finds Three New Worlds

  • Released Monday, July 29, 2019
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This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. Insets show information about the planets, including their relative sizes, and how they compare to Earth. Temperatures given for TOI 270’s planets are equilibrium temperatures, calculated without the warming effects of any possible atmospheres. Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger

This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. Insets show information about the planets, including their relative sizes, and how they compare to Earth. Temperatures given for TOI 270’s planets are equilibrium temperatures, calculated without the warming effects of any possible atmospheres.

Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered three new worlds -- one slightly larger than Earth and two of a type not found in our solar system orbiting a nearby star. The planets straddle an observed gap in the sizes of known planets and promise to be among the most curious targets for future studies.

TESS Object of Interest (TOI) 270 is a faint, cool star more commonly identified by its catalog name: UCAC4 191-004642. The M-type dwarf star is about 40% smaller than the Sun in both size and mass, and it has a surface temperature about one-third cooler than the Sun’s. The planetary system lies about 73 light-years away in the southern constellation of Pictor.

The innermost planet, TOI 270 b, is likely a rocky world about 25% larger than Earth. It orbits the star every 3.4 days at a distance about 14 times closer than Mercury orbits the Sun. Based on statistical studies of known exoplanets of similar size, the science team estimates TOI 270 b has a mass around 1.9 times greater than Earth’s.

The other two planets, TOI 270 c and d, are, respectively, 2.4 and 2.1 times larger than Earth and orbit the star every 5.7 and 11.4 days. Although only about half its size, both may be similar to Neptune in our solar system, with compositions dominated by gases rather than rock, and they likely weigh around 7 and 5 times Earth’s mass, respectively.

All of the planets are expected to be tidally locked to the star, which means they only rotate once every orbit and keep the same side facing the star at all times, just as the Moon does in its orbit around Earth.

Planet c and d might best be described as mini-Neptunes, a type of planet not seen in our own solar system. The researchers hope further exploration of TOI 270 may help explain how two of these mini-Neptunes formed alongside a nearly Earth-size world.

GIF version.Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Temperatures given for TOI 270 planets are equilibrium temperatures, calculated without taking into account the warming effects of any possible atmospheres. Credit: NASA’s Goddard Space Flight Center

GIF version.

Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Temperatures given for TOI 270 planets are equilibrium temperatures, calculated without taking into account the warming effects of any possible atmospheres.

Credit: NASA’s Goddard Space Flight Center

Video version of above.

Credit: NASA’s Goddard Space Flight Center

The TOI 270 system is so compact that the orbits of Jupiter and its moons in our own solar system offer the closest reasonable comparison, as illustrated here. Credit: NASA’s Goddard Space Flight Center

The TOI 270 system is so compact that the orbits of Jupiter and its moons in our own solar system offer the closest reasonable comparison, as illustrated here.

Credit: NASA’s Goddard Space Flight Center

GIF version.This illustration compares the size of the TOI 270 system with that of the Sun and the orbital distance of Mercury. None of TOI 270's planets orbit in the so-called habitable zone (green band), the range of stellar distances where conditions could allow liquid water to exist on a planet's surface.Credit: NASA’s Goddard Space Flight Center

GIF version.

This illustration compares the size of the TOI 270 system with that of the Sun and the orbital distance of Mercury. None of TOI 270's planets orbit in the so-called habitable zone (green band), the range of stellar distances where conditions could allow liquid water to exist on a planet's surface.

Credit: NASA’s Goddard Space Flight Center

Video version of the above.

Credit: NASA’s Goddard Space Flight Center

Unlabeled version of infographic. This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. The star and planet orbits are shown to scale; the larger planet illustrations show their relative sizes. Credit: NASA’s Goddard Space Flight Center

Unlabeled version of infographic.

This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. The star and planet orbits are shown to scale; the larger planet illustrations show their relative sizes.

Credit: NASA’s Goddard Space Flight Center

GIF version.Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Wide version with no text Credit: NASA’s Goddard Space Flight Center

GIF version.

Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Wide version with no text

Credit: NASA’s Goddard Space Flight Center

GIF version, wide.Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Temperatures given for TOI 270 planets are equilibrium temperatures, calculated without taking into account the warming effects of any possible atmospheres. Credit: NASA’s Goddard Space Flight Center

GIF version, wide.

Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Temperatures given for TOI 270 planets are equilibrium temperatures, calculated without taking into account the warming effects of any possible atmospheres.

Credit: NASA’s Goddard Space Flight Center

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This page was originally published on Monday, July 29, 2019.
This page was last updated on Wednesday, May 3, 2023 at 1:45 PM EDT.

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