Results 1 to 10 of about 12,976 (291)
Redefining the Empirical ZZ Ceti Instability Strip [PDF]
Astrophysical Journal, 2004 We use the new ZZ Ceti stars (hydrogen atmosphere white dwarf variables; DAVs) discovered within the Sloan Digital Sky Survey (Mukadam et al. 2004) to re-define the empirical ZZ Ceti instability strip. This is the first time since the discovery of white dwarf variables in 1968 that we have a homogeneous set of spectra acquired using the same instrument
Anjum S Mukadam +2 more
exaly +9 more sources
A new instability strip for hot degenerates [PDF]
Space Science Reviews, 1980 A completely new kind of variable star has recently been discovered (McGraw, et. al. 1979). Designated as PG1159-035 (hereafter PG) this star is distinguished not only by the complete lack of hydrogen in its spectrum but also by an effective temperature that exceeds 8 × 104 K (McGraw, private communication).
Sumner G Starrfield, Arthur N Cox
exaly +4 more sources
Empirical instability strip for classical Cepheids
Astronomy & Astrophysics, 2023 Aims. The aim of this study is to determine empirical intrinsic edges of the classical Cepheids instability strip (IS) in the Small Magellanic Cloud (SMC) galaxy; we considered various effects that alter its shape, and compared them with theoretical ...
Espinoza-Arancibia Felipe +2 more
doaj +9 more sources
IS POLARIS LEAVING THE CEPHEID INSTABILITY STRIP?
Odessa Astronomical Publications, 2017 Although Polaris is generally regarded as an overtone pulsator that may soon switch to pulsation in the fundamental mode, it is argued that the variable is actually crossing the instability strip for the first time and is in the process of leaving the ...
D. G. Turner
doaj +3 more sources
The Instability Strip for Pre–main-sequence Stars [PDF]
Astrophysical Journal, 1998 We investigate the pulsational properties of Pre--Main-Sequence (PMS) stars by means of linear and nonlinear calculations. The equilibrium models were taken from models evolved from the protostellar birthline to the ZAMS for masses in the range 1 to 4 solar masses.
M Marconi, Francesco Palla
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A NEW MAPPING OF THE CEPHEID INSTABILITY STRIP
Odessa Astronomical Publications, 2017 Results are presented for a new mapping of the instability strip for Milky Way Cepheids based upon eld reddenings for 40 stars (mainly members of open clusters and associations), color excesses for 53 stars obtained from reddening-independent systems ...
David G. Turner
doaj +3 more sources
Softening and instability evolution of strip coal pillar under water immersion in goaf [PDF]
Scientific ReportsThe softening and instability of the coal pillar caused by water immersion is the primary factor contributing to water inrush in the goaf of the same layer.
Xu Wang +9 more
doaj +2 more sources
A Theoretical γ Doradus Instability Strip
Astrophysical Journal, 2003 In this paper, we present the first theoretical γ Doradus instability strip. We find that our model instability strip agrees very well with the previously established, observationally based, instability strip of Handler & Shobbrook. We stress, as do Guzik et al., that the convection zone depth plays the major role in the determination of our ...
Anthony B Kaye, Joyce A Guzik
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Analysis of the abnormal wear of the pantograph contact strip through combined experimental and simulation approaches [PDF]
Scientific ReportsThe carbon contact strip of pantograph collects current from the overhead catenary to power the train, inevitably causing wear to the contact surface. This paper addresses the abnormal wear of the pantograph carbon contact strip, a challenged accident ...
Xingshuai Zhi +8 more
doaj +2 more sources
Toward an Empirical Determination of the ZZ Ceti Instability Strip
Astrophysical Journal, 2005 We present atmospheric parameters for a large sample of DA white dwarfs that are known to be photometrically constant. For each star, we determine the effective temperature and surface gravity by comparing high signal-to-noise ratio optical spectra to the predictions of detailed model atmosphere calculations.
A Gianninas, P Bergeron, G Fontaine
exaly +3 more sources