2009A&A...505..227W


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.29CET16:13:06

2009A&A...505..227W - Astronomy and Astrophysics, volume 505, 227-237 (2009/10-1)

Structure and spectra of irradiated secondaries in close binaries. A model calculation of the pre-cataclysmic variable UU Sagittae.

WAWRZYN A.C., BARMAN T.S., GUENTHER H.M., HAUSCHILDT P.H. and EXTER K.M.

Abstract (from CDS):

The standard stellar model atmosphere ignores the influence of external radiation. This assumption, while sufficient for most stars, fails for many short-period binaries. In setting up combined model atmospheres for close binaries, we want to constrain the parameters of both components, especially in the case of a hot primary component strongly influencing its cool secondary companion. This situation can be found after common envelope evolution (CEE). The status of both components today allows one to retrace the CEE itself. We used our stellar atmosphere code PHOENIX, which includes the effect of irradiation in its radiation transport equation, to investigate the close binary star UU Sge. We combined our calculated spectra of both components, weighted by their visible size, and adjusted the input parameters until reasonable agreement with observations is reached. We derive a range of 80000-85000K for the effective temperature of the primary (Teff,p) and give a rough estimate for the primary's abundances, particularly the nitrogen enrichment. The heated day-side of the secondary has an apparent ``effective'' or equilibrium temperature of 24000-26000K, nearly independent of its intrinsic luminosity. It shows an enhancement in nitrogen and carbon. The evolution of the primary and secondary stars were strongly influenced by the other's presence. Radiation from the primary on the secondary's day-side is still an important factor in understanding the secondary's atmospheric structure.

Abstract Copyright:

Journal keyword(s): radiative transfer - stars: abundances - binaries: eclipsing - binaries: close - stars: atmospheres - stars: individual: UU Sge

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 PG 1144+005 WD* 11 46 35.2287794057 +00 12 33.539708785   14.59 14.9     PG1159 79 0
2 PN A66 46 PN 18 31 18.290 +26 56 12.86   14.88 15.07     O9k 156 0
3 PN A66 63 PN 19 42 10.2896210362 +17 05 14.458035229           sdO+G: 195 1

    Equat.    Gal    SGal    Ecl

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2020.11.29-16:13:06

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