A newfound solar system boasting six confirmed exoplanets and a potential seventh is enriching astronomers' understanding of planet formation and evolution. Led by researchers at the University of California, Irvine, a team has leveraged a global array of observatories and instruments to compile the most precise measurements yet of the exoplanets' masses, orbital properties, and atmospheric features.
Published today in The Astronomical Journal, the team's paper unveils findings from the TESS-Keck Survey, offering a comprehensive profile of the exoplanets encircling TOI-1136, a dwarf star situated more than 270 light years away in the Milky Way galaxy. This study follows the team's initial observations of the star and exoplanets in 2019, utilizing data from the Transiting Exoplanet Survey Satellite. This data initially provided estimates of the exoplanets' masses by tracking transit timing variations, a method gauging the gravitational influence planets exert on each other.
For their latest investigation, the researchers combined TTV data with a radial velocity analysis of the star. Employing the Automated Planet Finder telescope at California's Lick Observatory and the High-Resolution Echelle Spectrometer at Hawaii's W.M. Keck Observatory, they detected subtle variations in stellar motion via the redshift and blueshift of the Doppler effect. This technique enabled them to derive planetary mass measurements with unparalleled precision.
To achieve such precise insights into the planets of this solar system, the team constructed computer models using hundreds of radial velocity measurements layered atop TTV data. Lead author Corey Beard, a UCI Ph.D. candidate in physics, remarked that integrating these two types of data yielded unprecedented understanding of the system.
“It required extensive trial and error, but we were immensely satisfied with our outcomes after developing one of the most intricate planetary system models in exoplanet literature to date,” Beard commented.
The presence of numerous planets motivated the astronomy team to delve deeper into their research, as highlighted by co-author Paul Robertson, UCI associate professor of physics & astronomy.
“We saw TOI-1136 as a highly favorable research subject because multiple exoplanets in a system allow us to mitigate the effects of planet evolution influenced by the host star. This enables us to focus on individual physical mechanisms shaping these planets' properties,” Robertson explained.
He added that when astronomers compare planets across different solar systems, various factors can differ due to the unique characteristics of stars and their locations in distinct parts of the galaxy. By studying exoplanets within the same system, researchers can analyze planets that share similar histories.
TOI-1136, by stellar standards, is youthful at a mere 700 million years old, another aspect that has captivated exoplanet hunters. Robertson noted that young stars present both challenges and opportunities for study due to their heightened activity. Magnetism, sunspots, and solar flares are more pronounced and vigorous during this stage, influencing planets' atmospheres through radiation bursts and sculpting effects.
Source: University of California, Irvine