Four new exoplanets orbiting a nearby solar star discovered by TESS

MIT-led NASA mission finds a multi-planetary system that can be an ‘ideal laboratory’ to study planetary formation and evolution.

MIT researchers have discovered four new exoplanets orbiting a solar star just over 200 light-years from Earth. Due to the diversity of these planets and the brightness of their star, this system could be an ideal target for atmospheric characterization with the upcoming NASA James Webb Space Telescope. Tansu Daylan, a postdoc at the MIT Kavli Institute for Astrophysics and Space Research, led the study, which was published in The Astronomical Journal on January 25, 2021.

With further study, Daylan says, this bright star and its many planets could be critical to understanding how planets take shape and evolve. “In terms of characterizing planetary atmospheres around solar stars, it’s probably one of the best targets we’ll ever get,” he said of the results he presented earlier this month at the 237th meeting of the American Astronomical Society.

Transportation method

Daylan and his colleagues detected these planets with the Transiting Exoplanet Survey Satellite (TESS), an MIT-led NASA mission. To identify exoplanets with TESS, researchers are looking for changes in the amount of light coming from a star. A small dip in a star’s light can mean that a planet has passed in front of it, thus obstructing part of its light from reaching the earth. By measuring these passages, scientists can approximate the size of a planet, how long it takes to orbit its star and whether it has other planetary neighbors. Combined with other observation methods, such as measuring the gravitational effects a planet has on its host, scientists can determine if a planet is rocky, gaseous, hot or cold, and even if it has a thick or thin atmosphere. .

If the light of a distant star through the atmosphere of a exoplanet On the way to Earth, certain wavelengths of light will be absorbed by the gases in that atmosphere. When light reaches the earth, wavelengths of light corresponding to specific gases – such as water, carbon dioxide or methane – will be missing, informing scientists about the composition of the atmosphere. It can give astronomers important information about the environment, evolution and habitability of a planet. Although TESS cannot characterize atmosphere, the telescope is the key to determining which exoplanets should be preferred for atmospheric study by other higher-resolution telescopes such as NASAs. Hubble Space Telescope and the James Webb Space Telescope starting in the fall of 2021.

Using data from TESS as well as ground-based telescopes, Daylan determined that this star is home to a large, rocky inner planet, or super-Earth, and three outer planets that are only smaller than Neptune, known as sub-Neptunes. Compared to our own solar system, these planets live very close to their sun; their orbits range from 19 days to just under four days. This causes them to burn hot, with their average surface temperatures of 700 degrees Fahrenheit up to 1,500 F.

While it is likely that the planets will not house life, it gives astronomers much more data to work with; a short orbit allows regular passages and therefore more opportunities to explore the light moving through its atmosphere. However, there may also be undiscovered planets further in this system, perhaps even in the star’s habitable zone. Recently, another research team used the distinctive Exoplanet Satellite (CHEOPS) to confirm a fifth planet that takes 29 days to orbit the star.

The planet’s host, TOI-1233, will provide enough light for future study, Daylan said. The star is similar in size and temperature to our own sun, but because it is relatively close to the earth, it looks very bright compared to other stars. According to us, it is the brightest known solar star and one of the brightest stars that houses at least four orbiting planets. This is useful because a bright star gives astronomers more light to work with when they characterize the planets.

Stars with many exoplanets are especially exciting for astronomers as they offer new avenues for studying solar systems. “With multi-planetary systems, you hit the jackpot a bit,” Daylan says. ‘The planets come from the same disk matter around the same star, but in the end they are different planets with different atmospheres and different climates due to their different orbits. We therefore want to understand the fundamental processes of planet formation and evolution using this planetary system, which serves as a controlled experiment. ‘

TESS is a NASA Astrophysics Explorer mission led and managed by MIT in Cambridge, Massachusetts, and is managed by NASA’s Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Center for Astrophysics – Harvard and Smithsonian in Cambridge; MIT Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participating in the mission.

Read Four exoplanets – including a super-Earth planet – discovered by high school students for more information on this discovery.

Reference: “TESS Discovery of a Super-Earth and Three Sub-Neptunes Hosted by the Bright, Sun-like Star HD 108236” by Tansu Daylan, Kartik Pinglé, Jasmine Wright, Maximilian N. Günther, Keivan G. Stassun, Stephen R. Kane, Andrew Vanderburg, Daniel Jontof-Hutter, Joseph E. Rodriguez, Avi Shporer, Chelsea X. Huang, Thomas Mikal-Evans, Mariona Badenas-Agusti, Karen A. Collins, Benjamin V. Rackham, Samuel N. Quinn, Ryan Cloutier , Kevin I. Collins, Pere Guerra, Eric LN Jensen, John F. Kielkopf, Bob Massey, Richard P. Schwarz, David Charbonneau, Jack J. Lissauer, Jonathan M. Irwin, Özgür Bastürk, Benjamin Fulton, Abderahmane Soubkiou, Benkhaldoun Zouhair , Steve B. Howell, Carl Ziegler, César Briceño, Nicholas Law, Andrew W. Mann, Nic Scott, Elise Furlan, David R. Ciardi, Rachel Matson, Coel Hellier, David R. Anderson, R. Paul Butler, Jeffrey D. Crane, Johanna K. Teske, Stephen A. Shectman, Martti H. Kristiansen, Ivan A. Terentev, Hans Martin Schwengeler, George R. Ricker, Roland Vanderspe k, S ara Seager, Joshua N. Winn, Jon M. Jenkins, Zachory K. Berta-Thompson, Luke G. Bouma, William Fong, Gabor Furesz, Christopher E. Henze, Edward H. Morgan, Elisa Quintana, Eric B. Ting and Joseph D. Twicken, January 25, 2021, The Astronomical Journal.
DOI: 10.3847 / 1538-3881 / abd73e