“The catalog consists of thousands of radial velocity (RV) observations that reveal a fascinating mix of planet types beyond our solar system, from rare worlds with extreme environments to ones that could possibly support life,” W. M. Keck Observatory said in a statement.
The TESS-Keck Survey’s Mass Catalog provides astronomers with a rich resource for studying the environments and conditions of newly discovered exoplanets, particularly those that might harbor life.
The findings are detailed in the latest edition of The Astrophysical Journal Supplement.
The TESS-Keck Survey results provide the single largest contribution to understanding the physical nature and system architectures of the new planets TESS has discovered, said Alex Polanski, the lead author of the paper. Catalogs like this help astronomers contextualize individual worlds within the broader exoplanet population, he said.
Over three years, Polanski and an international team of astronomers analyzed TESS planetary data, incorporating 9,204 RV measurements. Of these, 4,943 were obtained over 301 observing nights using the Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES).The TESS-Keck Survey’s findings heavily rely on Doppler spectroscopy from Keck Observatory’s HIRES, which the U.S. science community has depended on for exoplanet studies for nearly thirty years, said Ian Crossfield, a co-author of the paper.
Additionally, the team acquired 4,261 RV measurements using the Automated Planet Finder at Lick Observatory in California. These combined measurements allowed them to determine the masses of 120 confirmed planets and six candidate planets.
RV measurements enable astronomers to detect and understand the properties of these exoplanetary systems, said Crossfield. When a star regularly wobbles back and forth, we can infer the presence of an orbiting planet and determine its mass, he said.
Two planets in the TESS-Keck Survey, TOI-1824 b and TOI-1798 c, exemplify the diversity of exoplanets and provide new insights into planetary classification and formation.
TOI-1824 b: A Superdense Sub-Neptune
TOI-1824 b, one of the densest sub-Neptunes in the catalog, stands out due to its unusual density. Despite being nearly 19 times the mass of Earth, it is only 2.6 times the size. Planets of similar size typically have masses between 6 and 12 times that of Earth, noted co-author Joseph Murphy.
TOI-1824 b: A Superdense Sub-Neptune (Photo: https://www.keckobservatory.org/
One hypothesis for its high density is that TOI-1824 b might have an Earth-like core surrounded by an exceptionally thin hydrogen-dominated atmosphere. Alternatively, it could possess a water-rich core beneath a steam atmosphere.
TOI-1798 c: A Rare, Extreme Super-Earth
TOI-1798, an orange dwarf (K-type star), hosts two planets: TOI-1798 b, a sub-Neptune with an eight-day orbit, and TOI-1798 c, a super-Earth with an ultra-short period (USP) orbit of less than 12 hours. This system is one of the few known with such an inner planet.
TOI-1798 c: A Rare, Extreme Super-Earth
USPs, like TOI-1798 c, orbit their stars so quickly that one year lasts less than half a day on Earth and due to their close proximity to their host stars, USPs are extremely hot, receiving over 3,000 times the radiation Earth receives from the Sun, likely causing them to lose any initial atmosphere, said Polanski