Navegação Ciências Exatas e da Terra por Autor "Córsico, Alejandro Hugo"
Resultados 1-20 de 31
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About the existence of warm H-rich pulsating white dwarfs
(2020) [Artigo de periódico]Context. The possible existence of warm (Teff ∼ 19 000 K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti stars, was predicted in theoretical studies more than 30 yr ago. These studies reported the occurrence of ... -
Asteroseismological measurements on PG 1159-035, the prototype of the GW Virginis variable stars
(2008) [Artigo de periódico]Aims. An asteroseismological study of PG 1159−035, the prototype of the GW Vir variable stars, has been performed on the basis of detailed and full PG1159 evolutionary models presented by Miller Bertolami & Althaus (2006, ... -
Asteroseismological study of massive ZZ Ceti stars with fully evolutionary models
(2013) [Artigo de periódico]We present the first asteroseismological study for 42 massive ZZ Ceti stars based on a large set of fully evolutionary carbon–oxygen core DA white dwarf models characterized by a detailed and consistent chemical inner ... -
Asteroseismology of ZZ Ceti stars with full evolutionary white dwarf models : II. The impact of AGB thermal pulses on the asteroseismic inferences of ZZ Ceti stars
(2018) [Artigo de periódico]Context. The thermally pulsing phase on the asymptotic giant branch (TP-AGB) is the last nuclear burning phase experienced by most low- and intermediate-mass stars. During this phase, the outer chemical stratification above ... -
Asteroseismology of ZZ Ceti stars with fully evolutionary white dwarf models : I. the impact of the uncertainties from prior evolution on the period spectrum
(2017) [Artigo de periódico]Context. 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 ... -
Comparing the asteroseismic properties of pulsating extremely low-mass pre-white dwarf stars and δ Scuti stars
(2017) [Artigo de periódico]We present the first results of a detailed comparison between the pulsation properties of pulsating Extremely Low-Mass pre-white dwarf stars (the pre-ELMV variable stars) and δ Scuti stars. The instability domains of these ... -
Comparing the asteroseismic properties of pulsating pre-extremely low mass white dwarf and δ Scuti stars
(2018) [Artigo de periódico]Context. Pulsating extremely low-mass pre-white dwarf stars (pre-ELMV), with masses between ~0.15 M⊙ and ~0.30 M⊙, constitute a new class of variable stars showing g- and possibly p-mode pulsations with periods between 320 ... -
Discovery of a new PG 1159 (GW Vir) pulsator
(2014) [Artigo de periódico]We report the discovery of pulsations in the spectroscopic PG 1159 type pre-white dwarf SDSS J075415.12 + 085232.18. Analysis of the spectrum by Werner et al. indicated Teff = 120 000 ± 10 000 K, log g = 7.0 ± 0.3, mass ... -
Evidence of thin helium envelopes in PG 1159 stars
(2008) [Artigo de periódico]We present evidence that PG 1159 stars could harbor He-rich envelopes substantially thinner than those predicted by current evolutionary models with current estimates of mass loss, which may be attributable to an extensive ... -
Kepler and TESS observations of PG 1159-035
(2022) [Artigo de periódico]PG 1159-035 is the prototype of the PG 1159 hot (pre-)white dwarf pulsators. This important object was observed during the Kepler satellite K2 mission for 69 days in 59 s cadence mode and by the TESS satellite for 25 days ... -
Measuring the evolutionay rate of cooling of ZZ Ceti
(2013) [Artigo de periódico]We have finally measured the evolutionary rate of cooling of the pulsating hydrogen atmosphere (DA) white dwarf ZZ Ceti (Ross 548), as reflected by the drift rate of the 213.13260694 s period. Using 41 yr of time-series ... -
New evolutionary sequences for hot h-deficient white dwarfs on the basis of a full account of progenitor evolution
(2009) [Artigo de periódico]We present full evolutionary calculations appropriate for the study of hot hydrogen-deficient DO white dwarfs, PG 1159 stars, and DB white dwarfs. White dwarf sequences are computed for a wide range of stellar masses and ... -
On the evolutionary status and pulsations of the recently discovered blue large-amplitude pulsators (BLAPs)
(2018) [Artigo de periódico]The blue large-amplitude pulsators (BLAPs) constitute a new class of pulsating stars. They are hot stars with effective temperatures of ~30 000K and surface gravities of log g ~ 4.9, that pulsate with periods in the range ... -
On the possible existence of short-period g-mode instabilities powered by nuclear-burning shells in post-asymptotic giant branch h-deficient (PG1159-TYPE) stars
(2009) [Artigo de periódico]We present a pulsational stability analysis of hot post-asymptotic giant branch (AGB) H-deficient pre-white dwarf stars with active He-burning shells. The stellar models employed are state-of-the-art equilibrium structures ... -
On the systematics of asteroseismological mass determinations of PG 1159 stars
(2008) [Artigo de periódico]Aims. We analyze systematics in the asteroseismological mass determination methods in pulsating PG 1159 stars. Methods. We compare the seismic masses resulting from the comparison of the observed mean period spacings with ... -
Probing the internal rotation of pre-white dwarf stars with asteroseismology : the case of PG 0122+200
(2011) [Artigo de periódico]We put asteroseismological constraints on the internal rotation profile of theGWVir (PG1159- type) star PG 0122+200. To this end we employ a state-of-the-art asteroseismological model for this star and assess the expected ... -
Probing the structure of Kepler ZZ Ceti stars with full evolutionary models-based asteroseismology
(2017) [Artigo de periódico]We present an asteroseismological analysis of four ZZ Ceti stars observed with the Kepler spacecraft: GD 1212, SDSS J113655.17+040952.6, KIC 11911480, and KIC 4552982, based on a grid of full evolutionary models of DA white ... -
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : I. Asteroseismology of the GW Virstars RX J2117+3412, HS 2324+3944, NGC 6905, NGC 1501, NGC 2371, and K 1−16
(2021) [Artigo de periódico]Context. The recent arrival of continuous photometric observations of unprecedented quality from space missions has strongly promoted the study of pulsating stars and caused great interest in the stellar astrophysics ... -
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : II. Discovery of two new GW Vir stars: TIC 333432673 and TIC 095332541
(2021) [Artigo de periódico]Context. The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its ... -
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : III. Asteroseismology of the DBV star GD 358
(2022) [Artigo de periódico]Context. The collection of high-quality photometric data by space telescopes, such as the completed Kepler mission and the ongoing TESS program, is revolutionizing the area of white-dwarf asteroseismology. Among the different ...
