Zobrazeno 41 - 50
of 192
pro vyhledávání: '"Córsico, Alejandro H."'
Autor:
De Gerónimo, Francisco C., Althaus, Leandro G., Córsico, Alejandro H., Romero, Alejandra D., Kepler, S. O.
The thermally pulsing phase on the asymptotic giant branch (TP-AGB) is the last nuclear burning phase experienced by most of low and intermediate mass stars. During this phase, the outer chemical stratification above the C/O core of the emerging whit
Externí odkaz:
http://arxiv.org/abs/1801.10589
Publikováno v:
A&A 614, A136 (2018)
The $\epsilon$ mechanism is a self-excitation mechanism of stellar pulsations which acts in regions inside the star where nuclear burning takes place. It has been shown that the $\epsilon$ mechanism can excite pulsations in models of hot pre-horizont
Externí odkaz:
http://arxiv.org/abs/1801.07287
Publikováno v:
A&A 607, A33 (2017)
Many pulsating low-mass white-dwarf stars have been detected in the last years in the field of our Galaxy. Given that some of them exhibit multiperiodic variation of brightness, it is possible to probe their interiors through asteroseismology. We pre
Externí odkaz:
http://arxiv.org/abs/1708.00482
Autor:
Camisassa, María E., Althaus, Leandro G., Rohrmann, René D., García-Berro, Enrique, Torres, Santiago, Córsico, Alejandro H., Wachlin, Felipe C.
We present a set of full evolutionary sequences for white dwarfs with hydrogen-deficient atmospheres. We take into account the evolutionary history of the progenitor stars, all the relevant energy sources involved in the cooling, element diffusion in
Externí odkaz:
http://arxiv.org/abs/1703.05340
Autor:
Córsico, Alejandro H.
At present, a large number of pulsating white dwarf (WD) stars is being discovered either from Earth-based surveys such as the Sloan Digital Sky Survey, or through observations from space (e.g., the Kepler mission). The asteroseismological techniques
Externí odkaz:
http://arxiv.org/abs/1703.00934
Publikováno v:
A&A 600, A73 (2017)
We present a theoretical assessment of the expected temporal rates of change of periods ($\dot{\Pi}$) for low-mass ($M_{\star}/M_{\sun} \lesssim 0.45$) and extremely low-mass (ELM, $M_{\star}/M_{\sun} \lesssim 0.18-0.20$) white-dwarf stars, based on
Externí odkaz:
http://arxiv.org/abs/1701.08880
Autor:
De Gerónimo, Francisco C., Althaus, Leandro G., Córsico, Alejandro H., Romero, Alejandra D., Kepler, S. O.
ZZ Ceti stars are pulsating white dwarfs with a carbon-oxygen core build up during the core helium burning and thermally pulsing Asymptotic Giant Branch phases. Through the interpretation of their pulsation periods by means of asteroseismology, detai
Externí odkaz:
http://arxiv.org/abs/1611.10298
Autor:
Althaus, Leandro G., De Gerónimo, Francisco C., Córsico, Alejandro H., Torres, Santiago, García--Berro, Enrique
Some globular clusters host multiple stellar populations with different chemical abundance patterns. This is particularly true for $\omega$ Centauri, which shows clear evidence of a helium- enriched sub-population characterized by a helium abundance
Externí odkaz:
http://arxiv.org/abs/1611.06191
Publikováno v:
A&A 595, A45 (2016)
In the absence of a third dredge-up episode during the asymptotic giant branch phase, white dwarf models evolved from low-metallicity progenitors have a thick hydrogen envelope, which makes hydrogen shell burning be the most important energy source.
Externí odkaz:
http://arxiv.org/abs/1606.04367
Autor:
Córsico, Alejandro H., Romero, Alejandra D., Althaus, Leandro G., García-Berro, Enrique, Isern, Jordi, Kepler, S. O., Bertolami, Marcelo M. Miller, Sullivan, Denis J., Chote, Paul
We employ an asteroseismic model of L19-2, a relatively massive ($M_{\star} \sim 0.75 M_{\sun}$) and hot ($T_{\rm eff} \sim 12\,100$ K) pulsating DA (H-rich atmosphere) white dwarf star (DAV or ZZ Ceti variable), and use the observed values of the te
Externí odkaz:
http://arxiv.org/abs/1605.06458