On the shock-induced variability of emission lines in M-type Mira variables: I. Observational data

He. Richter and P.R. Wood

Astronomy & Astrophysics, 369, 1027-1047 (2001)

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Abstract:

We present time-resolved observations of metallic emission lines of Mg I, Mn I, Si I, Fe I and Fe II, including forbidden emission lines of [Fe II], for the six M-type Mira variables RR Sco, R Aql, R Car, R Leo, S Scl and R Hya, which range in period from 281 to 389 days. Data is also presented for the Balmer emission lines Hgamma, Hdelta, Hzeta and Heta. The observations were carried out in the optical wavelength region 3600-5700Å. Narrow-slit observations with dispersion of 1.53 km/(s pixel) and a 3-pixel resolution of 4.6 km/s were made in some cases while most observations were done with a wide slit corresponding to a resolution of 15.3 km/s. The variation of line shape, flux and velocity with phase is discussed. The data presented in this paper will be used in subsequent papers for comparison with detailed models of the emission from shock waves in the upper atmospheric
layers of Mira variables. It is in these important upper layers that dust formation occurs and mass loss is initiated.

Keywords:

line: profiles -- shock waves -- stars: circumstellar matter -- stars: late-type -- stars: variables: general