TESS probe finds first potential planets
An artist’s conception shows NASA’s Transiting Exoplanet Survey Satellite, or TESS, with an alien sun and planet in the background. (NASA / GSFC Illustration)
Astronomers on the team for NASA’s Transiting Exoplanet Survey Satellite mission, or TESS, are reporting their first potential planet discoveries, just days after the spacecraft’s first science image was unveiled.
The first reported candidate planet was detected orbiting a star known as Pi Mensae, a sunlike yellow dwarf star nearly 60 light-years from Earth that was already known to harbor a world that’s more than 10 times as massive as Jupiter.
The newly detected prospect is closer to its parent star in the southern constellation Mensa, making a complete orbit every 6.3 Earth days.
In a paper published on the ArXiv pre-print website and submitted to the journal Astronomy & Astrophysics, the team’s scientists say Pi Mensae c appears to be about twice as wide as Earth and 4.5 times as massive. Its density is estimated as roughly equal to water’s density, which suggests the planet is a super-Earth that “may have held on to a significant atmosphere,” the scientists say.
The second candidate planet orbits a red dwarf star known as LHS 3844, 49 light-years away in the constellation Indus. LHS 3844 b is thought to be a “hot Earth,” with a diameter about a third wider than Earth’s. It swings around its sun every 11 hours.
Because they’re much fainter than the sun, red dwarfs have habitable zones that are closer in than the zone in our own solar system. But the scientists behind the discovery don’t hold out much hope that LHS 3844 b would be habitable.
“It is unclear what type of atmosphere the planet might have if any,” they write in their ArXiv paper, which has been submitted to Astrophysical Journal Letters. “If the planet formed at or near this location, its primordial atmosphere could have been completely stripped away during the host star’s youth.”
TESS, which was launched in April, identifies planets based on the subtle dimming of starlight that results when an alien world crosses the disk of its parent star. This transit method has been used by NASA’s Kepler mission to detect more than 2,000 confirmed planets beyond our solar system, and there’s a chance TESS could find that many more.
In both of the newly reported cases, the researchers have cross-checked TESS’ findings against observations from other telescopes and data sets. However, the finds will be considered “candidate planets” rather than confirmed planets pending further verification.
Even though the discoveries have yet to be confirmed, the fact that they popped up so early in TESS’ two-year science mission “suggests that the prospects for future discoveries are bright,” LHS 3844 b’s discovery team says.
“It is worth remembering that 90 percent of the sky has not yet been surveyed by either TESS or Kepler,” the astronomers say.
That sentiment was seconded in tweets from the TESS science team and from Thomas Zurbuchen, NASA’s associate administrator for science:
On discovery of two candidate planets in @NASA_TESS's first data, @TESSatMIT Deputy Director of Science @ProfSaraSeager @MIT said "The team is excited about what TESS might discover next. We do know that planets are out there, littering the night sky, just waiting to be found." pic.twitter.com/TbCoP2Ak84
— NASA_TESS (@NASA_TESS) September 21, 2018
"It is rewarding to see years of work that the team -engineers, scientists, & support staff- poured into the dream of @NASA_TESS become the reality of discovered planets. This is just the beginning; we can't wait to see what's next." –@PadiBoyd @NASAGoddard TESS Project Scientist pic.twitter.com/Xe16Tb3yqz
— NASA_TESS (@NASA_TESS) September 21, 2018
How exciting! Congrats to the @NASA_TESS team! This will be the first of many planet candidates discovered by the spacecraft. Over the next few years, it will continue to search new parts of the sky for worlds that orbit stars outside our solar system. https://t.co/fnZHjH0BCq
— Thomas Zurbuchen (@Dr_ThomasZ) September 19, 2018