Stars

The Gl 357 system (Image NASA's Goddard Space Flight Center/Chris Smith)

An article published in the journal “Astronomy & Astrophysics” reports the discovery of three exoplanets in the system of the red dwarf GJ 357. A team of researchers led by Rafael Luque of the Canary Islands Astrophysics Institute identified the innermost exoplanet, named GJ 357 b, thanks to the observations conducted by NASA’s TESS space telescope while the other two, named GJ 357 c and GJ 357 d, were discovered using the radial velocity method thanks to data collected over twenty years of observations of various ground-based telescopes. The three exoplanets could all be rocky and the outermost is within ​​its star system’s habitable zone.

A representation of the main characteristics of the TOI 270 system's exoplanets (Image NASA’s Goddard Space Flight Center/Scott Wiessinger)

An article published in the journal “Nature Astronomy” reports the discovery of three exoplanets in the system of the red dwarf indicated in the research as TOI (Tess Object of Interest) 270 because it was studied using NASA’s TESS space telescope. They’re a super-Earth and two mini-Neptunes, all with orbits very close to their star. A team of researchers used observations made by TESS and follow-up observations with other telescopes to confirm the existence of the three exoplanets and provide some estimates of their characteristics, useful also because the two mini-Neptunes could provide information to understand the mechanisms of formation of planets of that type but also of rocky ones.

Artistic representation of a gaseous planet in a binary system (Image NASA/JPL-Caltech/T. Pyle)

An article published in “The Astrophysical Journal Letters” reports the discovery of a gaseous exoplanet in the DS Tuc binary system thanks to the use of NASA’s TESS space telescope. A team of astronomers coordinated by Dartmouth College, New Hampshire, USA, conducted this research on the exoplanet named DS Tuc Ab, which has an estimated age of about 45 million years, a sort of preteen. It has completed its growth but it’s still in a phase in which changes take place, all useful information to understand the formation and evolution of the planets.

LTT 1445 aka LTT 1445ABC (Image NASA / ESA / Hubble)

An article to be published in “The Astronomical Journal” reports the discovery of a super-Earth that was cataloged as LTT 1445Ab thanks to NASA’s TESS space telescope in a research coordinated by the Harvard-Smithsonian Center for Astrophysics. This exoplanet orbits a red dwarf and from the estimates seem too close to it to have the potential to host life forms similar to the Earth’s but it’s interesting because that star has two companions, red dwarfs as well, and orbits them.

Using red giants to estimate the speed of the universe expansion

An article being published in “The Astrophysical Journal” reports a new attempt to calculate the speed of the universe expansion, this time using red giant stars as a reference. A team of researchers coordinated by Carnegie Institution for Science and University of Chicago and led by astronomer Wendy Freedman used observations made with the Hubble space telescope to perform that calculation. The result has a probability peak at 69.8 km/s per megaparsec, between the values ​​calculated using the two methods that provided discrepant values.