Two rocky exoplanets discovered around nearby star

Tomasz Nowakowski is a writer for Phys.org.

Two rocky alien worlds have been detected by NASA using the TESS satellite. The newly discovered exoplanets are two times larger than the Earth. The paper was published on arXiv.org.

TESS is looking for transiting exoplanets by surveying 200,000 stars near the sun. Over 5,600 candidate exoplanets have been identified so far, of which 205 have been confirmed.

A team led by Rafael Luque of the University of Chicago confirmed the existence of two more planets. There are transit signals in the light curve of the bright M dwarf HD 260655. The planetary nature of these signals was confirmed by archival and new preciseRV measurements.

The discovery and characterization of a multiplanetary system is presented in this work. Two small planet candidates that were confirmed with independent RV data from the HIRES and CARMEANES instruments were detected by transit observations from TESS.

HD 260655 b is the exoplanet that is closer to the parent star. It is 2.14 times more massive than our planet and has a density level of 6.2 g/ cm 3. HD 260655 b travels at a distance of around 0.03AU from its host. The equilibrium temperature was 709 K.

HD 260655 c is larger and more massive than its neighbor. The results show that it has a radius of 1.53 and a mass of 3.09 Earth masses. The density of this planet was calculated to be 4.7 g/ cm 3. HD 260655 c is separated from the parent star by 0.047AU, has anorbital period of 5.7 days, and equilibrium temperature of 557 K.

The star HD 260655 is about 56 percent smaller and less massive than the sun and is located some 32.6 light years away. The star is between two and eight billion years old and has a metallicity level of -0.43. HD 260655 has an apparent brightness of 6.7 mag and an effective temperature of 3,803 K.

The densities of the two alien worlds were derived by the astronomer. HD 260655 b has a density in perfect agreement with the Earth, but the density of HD 260655 c suggests an internal composition void of iron and silicates.

HD 260655 is the fourth closest known multi-transiting planetary system. Due to the high apparent brightness of the host star, the two newfound planets would be excellent targets for further atmospheric studies.

More information: R. Luque et al, The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc. arXiv:2204.10261v2 [astro-ph.EP], arxiv.org/abs/2204.10261

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