Navegação Artigos de Periódicos por Assunto "Pulsacoes estelares"
Resultados 1-20 de 77
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2006 Whole Earth Telescope observations of GD358 : a new look at the prototype DBV
(2009) [Artigo de periódico]We report on the analysis of 436.1 hr of nearly continuous high-speed photometry on the pulsating DB white dwarf GD358 acquired with the Whole Earth Telescope (WET) during the 2006 international observing run, designated ... -
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 ... -
Amplitude and frequency variability of the pulsating DB white dwarf stars KUV 05134+2605 and PG 1654+160 observed with the Whole Earth Telescope
(2003) [Artigo de periódico]We have acquired new time series photometry of the two pulsating DB white dwarf stars KUV 05134+2605 and PG 1654+160 with the Whole Earth Telescope. Additional single-site photometry is also presented. We use all these ... -
An empirical test of the theory of crystallization in stellar interiors
(1997) [Artigo de periódico]Our theoretical calculations indicate that the massive pulsating DA white dwarf, BPM 37093, has a crystallized ion interior. Our estimates for the crystallized mass fraction depend on our assumption for the interior ... -
An observational limit to the evolutionary time scale of the 13,000 K white dwarf G117-B15A
(1990) [Artigo de periódico]Nature has provided us with a way of measuring the evolutionary time scale of some stars through aster oseismology, i.e., the study of stellar interiors through their intrinsic variations in brightness. By measuring the ... -
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 a star cooled by neutrino emission : the pulsating pre-white dwarf PG 0122+200
(1998) [Artigo de periódico]Observation of g-mode pulsations in the variable pre-white dwarf (GW Virginis) stars provides a unique means to probe their interiors and to study the late stages of stellar evolution. Multisite campaigns have in several ... -
Asteroseismology of RXJ 2117+3412, the hottest pulsating PG 1159 star
(2002) [Artigo de periódico]The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified ... -
Asteroseismology of the dov star PG 1159-035 with the Whole Earth Telescope
(1991) [Artigo de periódico]We report the results from 264.1 hr of nearly continuous time-series photometry on the pulsating pre-white dwarf star (DOV) PG 1159-035. The high-resolution power spectrum of this data set is dominated by power in the range ... -
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 ... -
Constraining the evolution of ZZ Ceti
(2003) [Artigo de periódico]We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf ) ZZ Ceti, also called R548. On the basis of observations that span 31 years, we conclude that the ... -
Delta Scuti Network observations of XX Pyx : detection of 22 pulsation modes and of short-term amplitude and frequency variations
(2000) [Artigo de periódico]We report multisite observations devoted to the main-sequence δ Scuti star XX Pyx, conducted as the 17th run of the Delta Scuti Network. Over 125 nights a total of 550 h of usable time-series photometric B- and V-filter ... -
A detection of the evolutionary time scale of the da white dwarf G117-B15A with the Whole Earth Telescope
(1991) [Artigo de periódico]We have detected the time rate of change for the main pulsation period of the 13,000 K DA white dwarf G117-B15A, using the Whole Earth Telescope (WET). The observed rate of period change, P = (12.0 ± 3.5) x 10- 15 s s - ... -
Direct measurement of a secular pulsation period change in the pulsating hot pre-white dwarf PG 1159-035
(1999) [Artigo de periódico]GW Vir (PG 1159[035) is the prototype of the class of multiperiodic, nonradially pulsating hot white dwarfs, and shows a strong pulsation mode at 516 s. All measurements to date of the secular variation of the 516 s pulsation ... -
Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS
(2022) [Artigo de periódico]We report the discovery of 74 new pulsating DA white dwarf stars, or ZZ Cetis, from the data obtained by the Transiting Exoplanet Survey Satellite mission, from Sectors 1 to 39, corresponding to the first 3 cycles. This ... -
Discovery of an ultramassive pulsating white dwarf
(2013) [Artigo de periódico]We announce the discovery of themostmassive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 ± 210 K WD with a log g = ... -
Discovery of five new massive pulsating white dwarf stars
(2013) [Artigo de periódico]Using the SOuthern Astrophysical Research telescope (SOAR) Optical Imager at the SOAR 4.1 m telescope, we report on the discovery of five new massive pulsating white dwarf stars. Our results represent an increase of about ...