Département d’Astronomie

Dec 9, 2024 | aanda.org | Matthias Kruckow |Département d’Astronomie |Université de Genève |Jeff Andrews

Home All issues Volume 692 (December 2024) A&A, 692 (2024) A141 Full HTML Issue A&A Volume 692, December 2024 Article Number A141 Number of page(s) 11 Section Stellar structure and evolution DOI https://doi.org/10.1051/0004-6361/202452356 Published online 06 December 2024 A&A, 692, A141 (2024) The formation of black holes in non-interacting isolated binaries 1,2⋆, 3,4, 1,2, 1,5, 1,2, 1,2, 6, 7,8, 9,6, 6, 6,10, 1,2,6 and 11,12 1 Département d’Astronomie, Université de Genève, Chemin Pegasi 51,...

Sep 3, 2024 | academic.oup.com | Département d’Astronomie |Université de Genève

Evolved very massive and low-metallicity stars (with zero-age-main-sequence mass ⁠, and metallicity ⁠) are predicted to end their lives in a pair-instability supernova (PISN), where the star is disrupted completely, leaving no remnant (e.g. Fowler & Hoyle 1964; Barkat, Rakavy & Sack 1967). These events eject a large amount of material and energy into the environment, enriching galaxies with more massive elements (Langer 2012).

Feb 20, 2024 | academic.oup.com | European Space Agency |European Space Research |Département d’Astronomie |Université de Genève

We report the discovery of a brown dwarf orbiting a M1 host star. We first identified the brown dwarf within the Next Generation Transit Survey data, with supporting observations found in TESS sectors 11 and 38. We confirmed the discovery with follow-up photometry from the South African Astronomical Observatory, SPECULOOS-S, and TRAPPIST-S, and radial velocity measurements from HARPS, which allowed us to characterise the system.

Nov 20, 2023 | academic.oup.com | Liverpool John Moores |Universidad Diego Portales |Département d’Astronomie

The onset of dust creation represents a milestone in the history of the Universe, as it relies on the adequate enrichment of the galaxy with metals, formation of sufficient dust particles in high-redshift supernova and interstellar medium (ISM) properties conducive to the survival (and growth) of dust (e.g. Draine 2003; Mancini et al. 2016; Gall & Hjorth 2018; Leśniewska & Michałowski 2019; Graziani et al. 2020; Dayal et al. 2022; Di Cesare et al. 2023).

Aug 1, 2023 | academic.oup.com | European Space Agency |European Space Research |Département d’Astronomie |Université de Genève

The magnetic activity level of low-mass stars is known to vary as a function of the physical properties of the star. Many studies have shown that the stellar mass and rotation are both important parameters that determine magnetic activity levels. In contrast, the impact of a star’s chemical composition on magnetic activity has received comparatively little attention.