Abstracts of Papers on Intrinsic Colours


Cramer N. (1982, A&A 112, 330)

Abstract

Estimators of the intrinsic Geneva [U-B] and [B-V] colours of O, B, and early A-type stars with log g > 3.5 are derived empirically in the three-parameter reddening-free (X,Y,Z) representation. These parameters resolve the effect pf temperature and gravity (i.e. MK types, parameters X and Y) as also of magnetic fields (Ap phenomenon, parameter Z). The estimators are shown to be affected essentially in the same sense as the true {U,B,V] colours by variations of the main astrophysical quantities. The intrinsic colours are thus correctly reproduced regardless of prior knowledge concerning evolutionary status, duplicity, rotational velocity or Ap chasracteristics of the stars observed. The empirical relations are shown to be in excellent agreement with Kurucz's (1979) atmosphere models, and the MK-type vs X, Y, [U-B]o, [B-V]o relations are given.


Kilkenny D., Whittet D.C.B. (1985, MNRAS 216, 127)

Abstract

Photoelectric uvby observations are presented for 43 late O-type to early A-type supergiants. The data are combined with published results to extend the Zhang determination of the intrinsic colour lines in the (b-y)/C1 diagram.


Meynet G., Hauck B. (1985, A&A 150, 163)

Abstract

The aim of this research note is to expose a photometric method to determine the intrinsic values of the Geneva colour index (B2-V1) for the supergiants of spectral types A and F. We present the different stages which led us to this objective, and test our method with a few stars belonging to clusters for which we found colour excesses in the literature. We indicate a list of stars classified as supergiants which behave photometrically as dwarfs.


Schuster W.J. (1984, Rev. Mex. 9, 53)

Abstract

We present data fundamental for the study of B-type stars. Interstellar reddening ratios, intrinsic colors, comparison stars, reddening-free indices, and calibrations for MK spectral types, effective temperature, and absolute visual magnitude are given. In particular we discuss briefly the use of 13C photometry for measuring stellar distances and for studying intrinsic excesses of Be and shell stars.


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Last update: 7 Novembre 1995