Astron. Astrophys. 334, 221-238 (1998)

2. Observations

Spectra of moderate resolving power () of the Group 1 stars ¹ were obtained by the author on six observing runs of two to three nights each between December 1995 and November 1996 at McDonald Observatory using the 2.1 m telescope equipped with the Sandiford Cassegrain echelle spectrograph (McCarthy et al. 1993) and a 1200 x 400 pixel Reticon CCD. Each star was observed at most once per night with exposure times typically between one and five minutes, resulting in spectra with S/N ratios between 150 and 300. In addition, a spectrum of CrB was obtained by David Lambert at the request of the author in June 1997, with the McDonald Observatory 2.7 m telescope equipped with an echelle spectrograph at the coudé focus (Tull et al. 1995). The 2048x2048 Tektronix CCD resulted in a resolving power of 65,000 and a S/N ratio of 300. The stars studied in Paper I, And and Boo, along with CrB make up the Group 2 stars.

For the purpose of studying line profile shapes, additional spectra were obtained at the author's request by David Lambert and Eric Bakker using the 2.7 m telescope at McDonald observatory equipped with the coudé echelle (Tull et al.) giving a resolving power (depending on the slit width) near 230,000 for 47 UMa, 70 Vir, and HD 114762, 180,000 for Cnc, and 115,000 for 51 Peg; the S/N ratios are in the range of 250 to 350, except for HD 114762, which is near 200. The spectral coverage is 4700 - 5800 Å for 47 UMa, 70 Vir and HD 114762 and 5700 - 7900 Å for 51 Peg with significant gaps between orders; the high-resolution spectra only cover about 20 Å per order, and the orders are separated by about 100 Å. Each observation was broken up into two or three exposures in order to detect and eliminate cosmic ray hits. The procedures followed in reducing all the spectra are the same as those described in Gonzalez & Lambert (1996) and in Paper I.

© European Southern Observatory (ESO) 1998

Online publication: May 12, 1998

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