The Transiting Exoplanet Survey Satellite has found three new worlds — one slightly bigger than Earth and two of a kind not present in our solar system — orbiting a close-by star. The planets straddle an observed gap within the sizes of known planets and promise to be among the most curious targets for future research.
TESS Object of Interest 270 is a faint, cool star more commonly recognized by its catalog name: UCAC4 191-004642. The M-type dwarf star is about 40% smaller than the Sun in each size and mass, and it has a surface temperature of about one-third cooler than the Sun. The planetary system lies about 73 light-years away within the southern constellation of Pictor.
“This technique is exactly what TESS was designed to seek out — small, temperate planets that cross, or transit, in front of an inactive host star, one missing excessive stellar activity, such as flares,” stated lead researcher Maximilian Günther, a Torres Postdoctoral Fellow on the Massachusetts Institute of Technology’s (MIT) Kavli Institute for Astrophysics and Space Research in Cambridge. “This star is quiet and very near us, and therefore a lot brighter than the host stars of comparable systems. With prolonged follow-up observations, we’ll quickly have the ability to decide the make-up of those worlds, set up if atmospheres are present and what gases they contain, and more.”A document describing the system was published in the journal Nature Astronomy and is now available online.