NASA discovers new exoplanet 3 times the size of Earth

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The space telescope launched past year as the successor to NASA's long-running and very successful Kepler turned in three exoplanets in its first three months of observations.

The National Aeronautics and Space Administration (Nasa) which launched Transiting Exoplanet Survey Satellite (Tess) for searching exoplanets in April, 2018 has discovered a third small planet outside our solar system.

TESS - that is, the Transiting Exoplanet Survey Satellite - is in the midst of surveying almost the entire sky for exoplanets orbiting stars up to 300 light-years away from Earth. Using ground-based telescopes, astronomers are now conducting follow-up observations on more than 280 TESS exoplanet candidates. Upon official confirmation, it could be the first planet discovered with the same size as Earth.

According to the study, the planet is 226 light-years away in the constellation Taurus. The bright star Pi Mensae is similar to the Sun in mass and size.

"It's the coolest small planet that we know of around a star this bright", said lead researcher Diana Dragomir, a post-doctoral student at the MIT.

An artist's visualization of the exoplanet LHS 3884b. The HD 21749B is three times bigger but approximately 23 times massive than our world. As hot as that is, it's cool considering the proximity to the host star, which is said to be nearly as bright as the sun. It's probably a "lava world", Huang said, given how close some of the planet's rocky surface is to its star.

Dubbed HD 21749b, it is described as a "sub-Neptune" exoplanet but is about three times the size of the Earth.

Researchers have focused on finding Earth-sized rocky planets with the right temperatures so that water, if any exists, would be liquid, a condition believed to be necessary for life.

What's even more exciting are hints the HD 21749 system holds a second candidate planet about the size of Earth that orbits the star every 8 days.

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The exoplant has a 36-day long orbit around a bright star in the Reticulum constellation.

To complicate matters, the star itself is relatively active, and Dragomir wasn't sure if the single transit she spotted was a result of a passing planet or a blip in stellar activity.

"We've confirmed three planets so far, and there are so many more that are just waiting for telescope and people time to be confirmed", Dragomir said.

TESS does this work by carving the sky up into overlapping sectors, studying each one for 27 days at a time. The satellite will spend the first year surveying the sky in the Southern Hemisphere, before swiveling around to take in the Northern Hemisphere sky.

Stay tuned for more news from TESS! "NASA's Kepler space telescope caught six of these events as they brightened during its first four years of operations". They determined that they should be able to find the signal again, in TESS's "sector 3" data - which they succeeded in doing. Its size is rare among exoplanets - planets beyond our solar system.

Those first three days of data were ignored, and errors were corrected in the rest of the data gathered.

The Kepler Space Telescope is sleeping and not expected to wake up since it's out of fuel. "The astronomical community's reaction to the early data release showed us that the world is ready to jump in and add to the mission's scientific bounty".

Ricker said TESS is operating so well that the spacecraft's lifetime could be extended well beyond its two-year primary mission to overlap with the missions of those future spacecraft - perhaps for several decades.

"Based on the brightness and shape of that flare, there's a lot of science that can be done", Fausnaugh says. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.