Almost all of the planets discovered so far (including the planets of the solar system) are confined to the plane of the Milky Way, and cannot see a panoramic view of the galaxy. us. However, astronauts at University Hawaii Institute for Astronomy (IfA) using telescopes at the WM Keck Observatory on Maunakea has discovered a rocky planet with a different view.
The planet is orbiting the star TESS Thing of Interest (TOI) 561, named for NASA TESS planetary hunting mission. TOI-561 belongs to a rare population of stars called galactic thick disk. Thick disc stars are chemically different, with fewer heavy trace elements (and especially less iron) than conventional Milky Way stars, suggesting their early formation, about 10 billion years ago. year. They also have moving motions that could be lifted out of the galactic plane, giving an overview of our own spiral galaxy.
“The changing rocky planet TOI-561 is one of the oldest rocky planets yet discovered. Its existence shows that the universe has been forming rocky planets almost since its inception 14 billion years ago, ”he said. Lauren Weiss, Postdoctoral Fellow Parent Beatrice Watson at IfA and team leader to find the TOI-561 planetary system.
The result was announced at a press conference at the January 2021 meeting of the Astronomical Society of America and was published in Astronomical Iris.
The changing rocky planet TOI-561 orbits its star, causing the planet to pass in front of the star as seen from Earth, blocking a fraction of the star’s light. The planet is small, with a radius just one and a half times larger than that on Earth. As a result, the light reduction it causes is miniscule, just 0.025% of the star’s brightness.
IfA Astronomers sensed this change in intensity and used the Echelle High Keck Observatory Resolution Spectrometer to determine the existence of the planet. By measuring the motion of the star due to the weight of the planet, they were able to find that the planet is three times the mass of the Earth. Combining this mass with the radius determined from the transmissions, the team concluded that the planet is more likely rocky, possibly with less iron than Earth.
TOI-561 at least two other planets move over the star, each of which has about twice the radius of the Earth and is too large and low in mass to be rocky.
For more information see the IfA website.