Zobrazeno 1 - 10
of 56
pro vyhledávání: '"Abia, Carlos"'
Autor:
Prantzos, Nikos, Abia, Carlos, Chen, Tianxiang, de Laverny, Patrick, Recio-Blanco, Alejandra, Athanassoula, E., Roberti, Lorenzo, Vescovi, Diego, Limongi, Marco, Chieffi, Alessandro, Cristallo, Sergio
Using a semi-analytical model of the evolution of the Milky Way, we show how secular evolution can create distinct overdensities in the phase space of various properties (e.g. age vs metallicity or abundance ratios vs age) corresponding to the thin a
Externí odkaz:
http://arxiv.org/abs/2305.13431
In 1981 Icko Iben Jr published a paper entitled 'The carbon star mystery: why do the low mass ones become such, and where have all the high mass ones gone?', where he discussed the discrepancy between the theoretical expectation and its observational
Externí odkaz:
http://arxiv.org/abs/2301.03978
Publikováno v:
A&A 670, A155 (2023)
In this work, we study whether the engulfment of a brown dwarf (BD) by a solar-like main-sequence (MS) star can significantly alter the structure of the star and the Li content on its surface. We perform 3D Smoothed Particle Hydrodynamics simulations
Externí odkaz:
http://arxiv.org/abs/2210.17363
Autor:
Guerço, Rafael, Smith, Verne V., Cunha, Katia, Ekström, Sylvia, Abia, Carlos, Plez, Bertrand, Meynet, Georges, Ramirez, Solange V., Prantzos, Nikos, Sellgren, Kris, Hayes, Cristian R., Majewski, Steven R.
The center of the Milky Way contains stellar populations spanning a range in age and metallicity, with a recent star formation burst producing young and massive stars. Chemical abundances in the most luminous stellar member of the Nuclear Star Cluste
Externí odkaz:
http://arxiv.org/abs/2208.10529
Publikováno v:
A&A 664, A45 (2022)
We extend here a previous investigation on the characteristics of Galactic carbon stars using more accurate EDR3 astrometry measurements. Based on a much larger statistics, we confirm that N- and SC-type carbon stars share a very similar luminosity f
Externí odkaz:
http://arxiv.org/abs/2206.00405
Autor:
Guerço, Rafael, Cunha, Katia, Smith, Verne V., Hayes, Christian R., Abia, Carlos, Lambert, David L., Jönsson, Henrik, Ryde, Nils
The chemical evolution of fluorine is investigated in a sample of Milky Way red giantstars that span a significant range in metallicity from [Fe/H] $\sim$ -1.3 to 0.0 dex. Fluorine abundances are derived from vibration-rotation lines of HF in high-re
Externí odkaz:
http://arxiv.org/abs/1909.08655
Autor:
Guerço, Rafael, Cunha, Katia, Smith, Verne V., Pereira, Claudio B., Abia, Carlos, Lambert, David L., de Laverny, Patrick, Recio-Blanco, Alejandra, Jönsson, Henrik
We present chemical abundances for the elements carbon, sodium, and fluorine in 15 red giants of the globular cluster M 4, as well as six red giants of the globular cluster $\omega$ Centauri. The chemical abundances were calculated in LTE via spectra
Externí odkaz:
http://arxiv.org/abs/1903.10127
Previous determinations of the oxygen isotopic ratios in AGB carbon stars were at odds with the existing theoretical predictions. We aim to redetermine the oxygen ratios in these stars using new spectral analysis tools and further develop discussions
Externí odkaz:
http://arxiv.org/abs/1611.06400
Extant chemical evolution models underestimate the Galactic production of Sr, Y and Zr as well as the Solar System abundances of s-only isotopes with 90
Externí odkaz:
http://arxiv.org/abs/1501.00544
Autor:
Cristallo, Sergio, Piersanti, Luciano, Straniero, Oscar, Gallino, Roberto, Dominguez, Inma, Abia, Carlos, DiRico, Gianluca, Quintini, Massimo, Bisterzo, Sara
By using updated stellar low mass stars models, we can systematically investigate the nucleosynthesis processes occurring in AGB stars, when these objects experience recurrent thermal pulses and third dredge-up episodes. In this paper we present the
Externí odkaz:
http://arxiv.org/abs/1109.1176