TOWARD A RESOLUTION OF THE BUMP AND BEAT CEPHEID MASS DISCREPANCIES

被引:142
作者
MOSKALIK, P
BUCHLER, JR
MAROM, A
机构
[1] Physics Department, University of Florida, Gainesville
[2] Copernicus Astronomical Center, 00-716 Warsaw
[3] Physics Department, Hebrew University, Jerusalem
关键词
ATOMIC DATA; CEPHEIDS; HYDRODYNAMICS; STARS; OSCILLATIONS;
D O I
10.1086/170975
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The extant beat and bump Cepheid mass discrepancy problems are reexamined with the new opacities of Iglesias and Rogers. Compared to calculations with the Los Alamos opacities, the period ratios P1/P0 and P2/P0 (1) are strongly reduced for any fixed stellar parameters (L, M, T(eff), X, Z) and (2) exhibit a novel, large sensitivity to luminosity and to metallicity. For the beat Cepheids the P1/P0 period ratios now yield masses between 4 and 7 M, in agreement with the other mass determinations. Nonlinear calculations still fail to give stable beat pulsations, however. The bump Cepheid masses are also considerably increased, and the conflict with the "standard" evolutionary masses is greatly reduced, although not completely eliminated. The nonlinear behavior of two model sequences is presented, Fourier analyzed, and compared with observation. Our calculations show that additional radial velocity observations in the crucial 11-14 day period range could provide an observational test for the opacities.
引用
收藏
页码:685 / 693
页数:9
相关论文
共 52 条
[1]  
ANDREASEN GK, 1988, ASTRON ASTROPHYS, V201, P72
[2]  
[Anonymous], 1958, HDP, DOI DOI 10.1007/978-3-642-45908-5_6
[3]   A RE-CALIBRATION OF THE LUMINOSITIES OF EARLY-TYPE STARS - ITS EFFECT ON THE CEPHEID LUMINOSITY SCALE [J].
BALONA, LA ;
SHOBBROOK, RR .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1984, 211 (02) :375-390
[4]  
BALONA LA, 1985, IAU COLL, V82, P17
[5]   FREQUENCY-PERIOD DISTRIBUTIONS OF CEPHEID VARIABLES IN GALAXIES IN LOCAL GROUP [J].
BECKER, SA ;
IBEN, I ;
TUGGLE, RS .
ASTROPHYSICAL JOURNAL, 1977, 218 (03) :633-653
[6]  
BECKER SA, 1985, IAU C, V82, P104
[7]   EVOLUTION OF CEPHEIDS .1. THE EFFECTS OF AN ENHANCED C-12(ALPHA,GAMMA)O-16 RATE [J].
BRUNISH, WM ;
BECKER, SA .
ASTROPHYSICAL JOURNAL, 1990, 351 (01) :258-262
[8]   THE EFFECTS OF A 2-1 RESONANCE IN NONLINEAR RADIAL STELLAR PULSATIONS [J].
BUCHLER, JR ;
KOVACS, G .
ASTROPHYSICAL JOURNAL, 1986, 303 (02) :749-765
[9]   A SURVEY OF BUMP CEPHEID MODEL PULSATIONS [J].
BUCHLER, JR ;
MOSKALIK, P ;
KOVACS, G .
ASTROPHYSICAL JOURNAL, 1990, 351 (02) :617-631
[10]   MILKY-WAY ROTATION AND THE DISTANCE TO THE GALACTIC-CENTER FROM CEPHEID VARIABLES [J].
CALDWELL, JAR ;
COULSON, IM .
ASTRONOMICAL JOURNAL, 1987, 93 (05) :1090-1105