Free Access
Volume 542, June 2012
Article Number A27
Number of page(s) 16
Section Stellar atmospheres
Published online 30 May 2012

Online material

Appendix A: Line profiles and radial velocities

Figure A.1 shows Hα and three other Balmer lines in BD+46°442 ordered according to the orbital phase, where each of the five orbital cycles (covering the first 1.5 years of observations) is designated with a different colour. A correlation with the orbital phase is obvious. The central absorption in Hα is not always aligned with the photospheric velocity, which means that the profile cannot be represented by a simple superposition of a broad emission line with a photospheric absorption line. Close to the giant’s inferior conjunction (φ = 0.75), Hα exhibits a double-peak emission line, while near superior conjunction (φ = 0.25) the blue peak is replaced by an extended blue absorption, as can also be seen in the higher Balmer lines.

Figure A.2 shows the behaviour of some metal lines and the CCF, which represents the behaviour of the majority of the photospheric lines that are symmetric and move with the orbital velocity. Low-excitation (χlow = 0−3 eV), strong (EW > 300 mÅ) lines, on the other hand, show additional circumstellar and interstellar (in Na I D) components, particularly for phases in the range φ = 0.9−1.1.

thumbnail Fig. A.1

Balmer lines as a function of the RV phase (φ = 0 corresponds to the maximum redshift). Different colours denote different orbital cycles. A solid vertical line marks our systemic velocity of  −98.9 km s-1, while dotted lines mark 50 km s-1 intervals from it. The arrows mark the photospheric velocity according to the CCF.

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thumbnail Fig. A.2

Same as in Fig. A.1, only for the CCF and the representative metal lines of different strengths: Ca II 4d-4f doublet, Fe II (42) triplet, and the Na I D doublet. In each panel, different line styles (solid, dashed, dotted) designate different members of the same multiplet.

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Table A.1

Radial velocities of BD+46°442.

© ESO, 2012

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