Nasa spacecraft spots gaseous planet 23 times the size of Earth

Source: The Guardian

Nasa spacecraft spots gaseous planet 23 times the size of Earth

‘Super-Earth’ among trio of planets and six supernovae detected by Tess mission

Lucy Campbell
Tue 8 Jan 2019 18.21 GMT

Three new planets and six supernovae outside our solar system have been observed by Nasa’s planet-hunting Tess mission in its first three months.

Since it started surveying the sky in July, the MIT-led Transiting Exoplanet Survey Satellite project has identified Pi Mensae b, a “super-Earth” that travels around its star every six days, and LHS 3844b, a rocky world with an orbit of only 11 hours.

The most recent discovery, an exoplanet named HD 21749b, has the longest orbital period at 36 days. It orbits a bright, nearby dwarf star about 53 light years away in the Reticulum constellation, and is thought to have a surface temperature of about 1,650C (3,000F). This is relatively cool considering its proximity to its star.

Diana Dragomir, a Hubble fellow at MIT’s Kavli Institute for Astrophysics and Space Research who led the discovery team, said: “It’s the coolest planet we know of around a star this bright. It’s very hard to find small planets that orbit farther from their stars, and are therefore cooler. But here we were lucky, and can now study this one in more detail.”

The new planet is 23 times the size of Earth, meaning it is likely to be gaseous rather than rocky, and it has an atmosphere more dense than Neptune or Uranus. Its discovery was announced by scientists at the annual American Astronomical Society meeting in Seattle.

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Read more: https://www.theguardian.com/science/2019/jan/08/nasa-spacecraft-planet-earth-tess-mission