Search Publications
Mapping the Galactic Metallicity Gradient with Open Clusters: The State-of-the-Art and Future Challenges
Cunha, Katia; Spina, Lorenzo; Magrini, Laura
In this paper, we make use of data collected for open cluster members by high-resolution spectroscopic surveys and programmes (i.e., APOGEE, Gaia-ESO, GALAH, OCCASO, and SPA). These data have been homogenised and then analysed as a whole. The resulting catalogue contains [Fe/H] and orbital parameters for 251 Galactic open clusters. The slope of th…
Milky Way Star Clusters and Gaia: A Review of the Ongoing Revolution
Cantat-Gaudin, Tristan
The unprecedented quality of the astrometric measurements obtained with the ESA Gaia spacecraft have initiated a revolution in Milky Way astronomy. Studies of star clusters in particular have been transformed by the precise proper motions and parallaxes measured by Gaia over the entire sky as well as Gaia's deep all-sky photometry. This paper pres…
RR Lyrae and Type II Cepheid Variables in Globular Clusters: Optical and Infrared Properties
Bhardwaj, Anupam
Globular clusters are both primary fossils of galactic evolution and formation and are ideal laboratories for constraining the evolution of low-mass and metal-poor stars. RR Lyrae and type II Cepheid variables are low-mass, radially pulsating stars that trace old-age stellar populations. These stellar standard candles in globular clusters are cruc…
Formation of Comets
Blum, Jürgen; Gundlach, Bastian; Bischoff, Dorothea
Questions regarding how primordial or pristine the comets of the solar system are have been an ongoing controversy. In this review, we describe comets' physical evolution from dust and ice grains in the solar nebula to the contemporary small bodies in the outer solar system. This includes the phases of dust agglomeration, the formation of planetes…
The Initial-Final Mass Relation of White Dwarfs: A Tool to Calibrate the Third Dredge-Up
Marigo, Paola
The initial mass-final mass relationship (IFMR) of white dwarfs (WD) represents a crucial benchmark for stellar evolution models, especially for the efficiency of mixing episodes and mass loss during the asymptotic giant branch (AGB) phase. In this study, we argue that this relation offers the opportunity to constrain the third dredge-up (3DU), wi…
Tidal Quality of the Hot Jupiter WASP-12b
Makarov, Valeri V.; Efroimsky, Michael
WASP-12b stands out among the planets of its class of hot Jupiters because of the observed fast orbital decay attributed to tidal dissipation. The measured rate of the orbital period change is Pṡorb=‑29±3ms/yr= ‑(9.2±1.0)×10‑10s/s. In the literature heretofore, all attempts to explain this high rate were based on the assumption that the orbital ev…
The Effect of Age on the Grouping of Open Clusters: The Primordial Group Hypothesis
Casado, Juan
The Primordial Group hypothesis states that only sufficiently young open clusters (OCs) can be multiple, and old OCs are essentially isolated. We tested this postulate through four different studies using a manual search of Gaia EDR3 and extensive literature. First, we revisited the work of de La Fuente Marcos and de La Fuente Marcos (2009), which…
The C/M Ratio of AGB Stars in the Local Group Galaxies
Yang, Ming; Ren, Yi; Jiang, Biwei +1 more
The number ratio of carbon-rich to oxygen-rich asymptotic giant branch (AGB) stars (the so-called C/M ratio) is closely related to the evolution environment of the host galaxy. This work studies the C/M ratio in 14 galaxies within the Local Group with the most complete and clean sample of member stars identified in our previous works. The borderli…
Solar Orbiter SWA Observations of Electron Strahl Properties Inside 1 AU
Verscharen, Daniel; Louarn, Philippe; Owen, Christopher J. +3 more
The Solar Wind Analyser (SWA) suite on Solar Orbiter includes an Electron Analyser System (SWA-EAS) which is capable of high temporal and angular resolution measurements of solar wind electrons in the energy range ∼1 eV to ∼5 keV. In this article we report early nominal phase observations of the suprathermal electron population at energies ≥70 eV …
Mechanical Properties of Cometary Surfaces
Vincent, Jean-Baptiste; Biele, Jens; Knollenberg, Jörg
Mechanical properties, in particular, strength (tensile, shear, compressive) and porosity, are important parameters for understanding the evolution and activity of comets. However, they are notoriously difficult to measure. Unfortunately, neither Deep Impact nor other comet observations prior to Rosetta provided firm data on the strength of cometa…