The planet has an orbit of 36 days and a surface temperature of about 300 degrees Fahrenheit.
"I'm very interested to know whether [it] has an Earth-like density to match its Earth-like radius - this will contribute to our understanding whether Earth-sized planets have diverse compositions or are all roughly similar to Earth", said Johanna Teske, a co-author of the report. The team, however, needed at least three transits to claim the discovery of a candidate planet and they did not find a third signal in the observations they reviewed.
She and her colleagues compared the pattern to the first full transit they had originally discovered, and found a near flawless match - an indication that the planet passed again in front of its star, in a 36-day orbit.
There might be yet another planet that's a bit smaller than Earth and orbits even closer to the star HD 21749, making a complete round every eight days.
The other two planets it has discovered are Pi Mensae c, a super-Earth that zips around its star in 6.3 days, and LHS 3844b, a rocky planet that flies around its planet in a whopping 11-hour orbit.
"We think this planet wouldn't be as gaseous as Neptune or Uranus, which are mostly hydrogen and really puffy. But here we were lucky, and can now study this one in more detail". The exoplanet lies in the stellar system K2-288, which has two dim, cool stars.
"It's a very exciting discovery due to how it was found, its temperate orbit and because planets of this size seem to be relatively uncommon", said Feinstein, who presented the discovery at the 233rd meeting of the American Astronomical Society in Seattle on Monday, Jan. 7.
As far as what the planet may be like, the jury is still out.
So the reprocessed, "cleaned-up" light curves were uploaded through the Exoplanet Explorers project on online platform Zooniverse, and the public was invited to "go forth and find us planets", Feinstein said. "TESS found as many in its first month".
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Asked about the timing of the operation during trade talks, Lu said resolving issues would help both countries and the world. Kaplan, Assistant Secretary for Fossil Energy Steven Winberg, and Under Secretary for International Affairs David Malpass.
"Some of the most interesting science occurs in the early days of a supernova, which has been very hard to observe before TESS", said Michael Fausnaugh, a TESS researcher at the MIT Kavli Institute.
Yet another team drew upon readings from Kepler as well as NASA's Spitzer Space Telescope to confirm the existence of a sixth planet circling a star known as K2-138, roughly 600 light-years from Earth.
TESS is in the process of scanning the entire southern sky, after which it will turn and canvass the northern sky.
Since it launched in April 2018, TESS, an MIT-led mission, has been monitoring the sky, sector by sector, for momentary dips in the light of about 200,000 nearby stars. Bright stars allow for easier followup study through ground- and space-based telescopes.
In addition to observing exoplanets, TESS has spotted many other types of astronomical phenomena, including comets and asteroids, flare stars and mutually eclipsing binary stars, white dwarf stars and supernovae. It's clear that the world is significantly larger than Earth, about twice the size, but it's located within what scientists consider the habitable zone of its system.
The exoplanet, called K2-288Bb, is within its star's habitable zone, which means liquid water could exist on its surface.
The object shares many characteristics with our planet despite sitting 1,400 light years away.
An illustration of NASA's Kepler space telescope.
In total, Kepler has found around 5,000 unconfirmed "candidate" exoplanets, with a further 2,500 "confirmed" exoplanets that scientists have since shown to be real.