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Cygnus X-1 contains a 21-solar mass black hole—Implications for massive star winds

Gou, Lijun; Byun, Do-Young; Bahramian, Arash +23 more

The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We used radio astrometry to refine the distance to the black hole x-ray binary Cygnus X-1, which we found to be 2.22_-0.17^+…

A compositional link between rocky exoplanets and their host stars

Bitsch, Bertram; Sousa, Sérgio G.; Martioli, Eder +17 more

Stars and planets both form by accreting material from a surrounding disk. Because they grow from the same material, theory predicts that there should be a relationship between their compositions. In this study, we search for a compositional link between rocky exoplanets and their host stars. We estimate the iron-mass fraction of rocky exoplanets …

GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star

Hellier, Coel; Latham, David W.; Quinn, Samuel N. +75 more

Ultrashort-period (USP) exoplanets have orbital periods shorter than 1 day. Precise masses and radii of USP exoplanets could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the USP planet GJ 367b using high-precision photometry and radial velocity observations. GJ 367b orbits …

Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal

Clemens, J. C.; Dufour, P.; Blouin, S. +4 more

Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the systems formed, which is analogous to how meteorite abundances inform our understanding of the early Solar Syste…