Four new exoplanets orbiting a star close to the sun discovered by TESS

WITH-LED NASA The mission finds a multi-planetary system that could be an “ideal laboratory” to study the formation and evolution of planets.

MIT researchers have discovered four new exoplanets orbiting a sun-like 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 future of NASA. James Webb Space Telescope. Tansu Daylan, post-doctoral fellow at MIT Kavli Institute for Astrophysics and Space Research, led the study published in The astronomical journal January 25, 2021.

With further study, Daylan says, this bright star and its many planets could be essential in understanding how planets take shape and evolve. “When it comes to characterizing the planetary atmospheres around sun-like stars, this is probably one of the best targets we’ll ever get,” he says of the results he presented earlier in the month at the 237th meeting of the American Astronomical Society.

Transit method

Daylan and his colleagues detected these planets with the Transit Exoplanet Survey Satellite (TESS), a NASA mission led by MIT. To identify exoplanets with TESS, researchers look for changes in the amount of light coming from a star. A small dip in a star’s light could mean that a planet has passed past it, preventing some of its light from reaching Earth. By measuring these transits, scientists can estimate 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 of a planet on its host star, researchers can determine whether a planet is rocky or gaseous, hot or cold, and even whether it has a thick atmosphere or thin.

If the light of a distant star passes through the atmosphere of a exoplanet on its way to Earth, certain wavelengths of light will be absorbed by the gases in this atmosphere. When light reaches Earth, wavelengths of light corresponding to specific gases – such as water, carbon dioxide, or methane – will be missing, informing scientists of the composition of the atmosphere. This can give astronomers vital information about a planet’s environment, evolution, and habitability. Although TESS cannot characterize atmospheres, the telescope is essential for identifying exoplanets that should be prioritized for atmospheric study by other higher resolution telescopes like that of NASA. The Hubble Space Telescope and the James Webb Space Telescope is scheduled to launch in fall 2021.

Using data from TESS as well as ground-based telescopes, Daylan determined that this star harbors a large rocky inner planet, or super-Earth, and three gaseous outer planets just smaller than Neptune, known as the 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 makes them extremely hot, with their average surface temperatures ranging from 700 degrees. Fahrenheit at 1500 F.

While this means the planets are unlikely to host life, it gives astronomers a lot more data to work with; a short orbit allows more frequent transits and therefore more opportunities to examine the light passing through its atmosphere. However, there may also be as yet undiscovered planets further in this system, possibly even in the star’s habitable zone. Recently, another research team used the Characteristic Exoplanet Satellite (CHEOPS) to confirm a fifth planet, which takes 29 days to orbit the star.

The planets’ host star, TOI-1233, will provide enough light for future study, Daylan says. The star is similar in size and temperature to our own sun, but because it is relatively close to Earth, it looks very bright compared to other stars. From our perspective, it is the brightest known solar star and one of the brightest stars to harbor at least four planets in transit. This is useful because a brighter star gives astronomers more light to work on when characterizing its planets.

Stars with many exoplanets are of particular interest to astronomers because they open up new avenues for studying solar systems. “With multi-planetary systems, you sort of hit the jackpot,” Daylan says. “The planets originate from the same disc of matter around the same star, but they end up being different planets with different atmospheres and different climates due to their different orbits. So, we would like to understand the fundamental processes of formation and evolution of planets using this planetary system, which acts as a controlled experiment.

TESS is a NASA astrophysical exploration mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center. Other 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 Baltimore Space Telescope Science Institute. More than a dozen universities, research institutes and observatories around the world participate in the mission.

Read Four Exoplanets – Including a Super-Terrestrial Planet – Discovered by High School Students to learn more about 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 Vanderspek, 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