https://boingboing.net/2022/12/15/star-15-light-years-away-has-two-earth-like-planets.html
The good news: two temperate planets with Earthlike-mass orbit a red dwarf star "only" 15 light years away. The bad news: that close to their star—0.045 AUs—they're tidally locked to it and the very hypothetical goldilocks climate band on the planet's surface suggests life not as we know it, if at all.
From phy.org:
An international scientific team led by researchers at the Instituto de Astrofísica de Canarias (IAC) has discovered the presence of two planets with Earth-like masses in orbit around the star GJ 1002, a red dwarf not far from the solar system. Both planets are in the habitability zone of the star.
"Nature seems bent on showing us that Earth-like planets are very common. With these two we now know 7 in planetary systems quite near to the sun," explains Alejandro Suárez Mascareño, an IAC researcher, who is the first author of the study accepted for publication in Astronomy & Astrophysics.
[...] The discovery was made during a collaboration between the consortia of the two instruments ESPRESSO and CARMENES. GJ 1002 was observed by CARMENES between 2017 and 2019, and by ESPRESSO between 2019 and 2021.
[...] "Either of the two groups would have had many difficulties if they had tackled this work independently. Jointly we have been able to get much further than we would have done acting independently," states Suárez Mascareño.
We report the discovery and characterisation of two Earth-mass planets orbiting in the habitable zone of the nearby M-dwarf GJ~1002 based on the analysis of the radial-velocity (RV) time series from the ESPRESSO and CARMENES spectrographs. The host star is the quiet M5.5~V star GJ~1002 (relatively faint in the optical, V∼13.8 mag, but brighter in the infrared, J∼8.3 mag), located at 4.84 pc from the Sun.
We analyse 139 spectroscopic observations taken between 2017 and 2021. We performed a joint analysis of the time series of the RV and full-width half maximum (FWHM) of the cross-correlation function (CCF) to model the planetary and stellar signals present in the data, applying Gaussian process regression to deal with the stellar activity.
We detect the signal of two planets orbiting GJ~1002. GJ~1002~b is a planet with a minimum mass mpsini of 1.08 ± 0.13 M⊕ with an orbital period of 10.3465 ± 0.0027 days at a distance of 0.0457 ± 0.0013 au from its parent star, receiving an estimated stellar flux of 0.67 F⊕. GJ~1002 c is a planet with a minimum mass mpsini of 1.36 ± 0.17 M⊕ with an orbital period of 20.202 ± 0.013 days at a distance of 0.0738 ± 0.0021 au from its parent star, receiving an estimated stellar flux of 0.257 F⊕. We also detect the rotation signature of the star, with a period of 126 ± 15 days.
GJ~1002 is one of the few known nearby systems with planets that could potentially host habitable environments. The closeness of the host star to the Sun makes the angular sizes of the orbits of both planets (∼ 9.7 mas and ∼ 15.7 mas, respectively) large enough for their atmosphere to be studied via high-contrast high-resolution spectroscopy with instruments such as the future spectrograph ANDES for the ELT or the LIFE mission.
Journal Reference:
A. Suárez Mascareño, E. González-Alvarez, M. R. Zapatero Osorio, et al., Two temperate Earth-mass planets orbiting the nearby star GJ 1002, A&A, 2022. DOI: 10.1051/0004-6361/202244991
