Classical cepheid masses: U Aquilae

被引：19

作者：

Evans, NR

Bohm-Vitense, E

Carpenter, K

Beck-Winchatz, B

Robinson, R

机构：

[1] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[2] Univ Washington, Dept Astron, Seattle, WA 98195 USA

[3] NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA

[4] NASA, Goddard Space Flight Ctr, Comp Sci Corp, Astron Programs, Greenbelt, MD 20771 USA

来源：

ASTROPHYSICAL JOURNAL | 1998年 / 494卷 / 02期

关键词：

binaries; spectroscopic; Cepheids; stars; fundamental parameters; individual (U Aquilae);

D O I：

10.1086/305242

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We have obtained medium-resolution spectra (lambda/Delta lambda similar to 20,000) of the hot binary companion to the classical Cepheid U Aql with the Goddard High Resolution Spectrograph on the Hubble Space Telescope (HST). These have been used to determine the orbital velocity amplitude. Combining this with the orbital velocity amplitude of the Cepheid from the ground-based orbit and the mass of the companion inferred from its spectral type, we measure a mass of the Cepheid of 5.1 +/- 0.7 M.. We discuss the full sample of Cepheids for which we have determined masses with HST (S Mus, V350 Sgr, Y Car, and U Aql) and also SU Cyg (mass from IUE). The HST masses are in agreement with the luminosities predicted by recent evolutionary tracks with moderate overshoot. This comparison, however, may be altered by reassessment of Cepheid distances based on Hipparcos parallaxes.

引用

页码：768 / 772

页数：5

共 28 条

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