39 light years away inside the Aquarius constellation, at least seven planets orbit an ultra-cool dwarf star star 12 times less massive than our sun. Only slightly larger than Jupiter, the star was discovered by the Spitzer telescope and the TRAPPIST observatory.
According to Rebecca Brinch, a sophomore double major in physics and astrophysics, scientists had discovered three possible planets orbiting the star over a year ago.
The star, named Trappist-1, was first discovered by Belgian astronomers in 2015 using transit photometry, a method which measures the regular and repeated shadows that are cast during transit.
CisternYard News was able to talk with Dr. Joe Carson, an Associate Professor in the Department of Physics and Astronomy, over Skype – when asked to describe the process through which scientists discovered the exoplanets using the Spitzer telescope, Carson answered, “In observing the star itself, they don’t directly see any of the planets. What they’re seeing though, is when the planet is passing in between the star and our perspective of the telescope, and because of that it causes a dimming of the starlight. It’s a very very small version of an eclipse.”
Carson, who mainly researches the direct imaging of extrasolar planets and circumstellar disks, also answered questions about the criteria needed for a planet to be considered “sustainable” and able to support life.
He stated that the newly discovered planets in the Trappist-1 system “are the correct distance [from the star] to have liquid water, or potentially have liquid water on the surface.”
The planets are roughly the mass of Earth, but are packed in much closer to each other than the planets in our solar system. In theory, these seven newly-discovered planets are able to sustain life, even though the star around which the planets orbit is considered cool (it is an M8 red dwarf star). The star is still extremely hot, but not as hot as our sun, but Carson believes it would still be able to provide enough heat for sustainable life on the planets.
Namely, the distance of each planet from its star makes them potential candidates for sustaining life. Since their orbits are so close to the star, they receive heat from it.
“The star is still, it is a star, even a cool star is very hot. It’s undergoing nuclear burning, so there’s nuclear explosions going on continuously from the star, so there’s heat coming off of it”, Carson attests.
However, more complications arise when bringing into account each planet’s orbit. When each planet makes a rotation, the same side is always facing the star. This means that if humans were to live on the planets, there would be continual sunshine on one side of the planet, and continual darkness on the other.
In addition, each planet has a perfectly circular orbit, opposed to oval-shaped, like Earth’s. If the planets had oval-shaped orbits, there would be huge tidal forces as they approached closer to the sun, and then away from it again.
Much research will have to be done to determine if life could sustain on these newly-discovered exoplanets, however, the fact that scientists have been able to discover planets and planetary systems dozens of light-years away is a remarkable feat.