We h a ve observed evidence for p-mode oscillations in the G0 IV star Boo V = 2:68. This represents the rst clear evidence of solar-like oscillations in a star other than the Sun. We used a new technique which measures uctuations in the temperature of the star via their e ect on the equivalent widths of the Balmer lines. The observations were obtained over six nights with the 2.5 m Nordic Optical Telescope on La Palma and consist of 12684 low-dispersion spectra. In the power spectrum of the equivalent-width measurements, we nd an excess of power at frequencies around 850 Hz period 20 minutes which consists of a regular series of peaks with a spacing of = 4 0 :3 Hz. We identify thirteen oscillation modes, with frequency separations in agreement with theoretical expectations. Similar observations of the daytime sky show the ve-minute solar oscillations at the expected frequencies.

A B S T R A C TWe present radial velocity measurements of the rapidly oscillating Ap (roAp) star a Cir, obtained from dual-site observations with medium-dispersion spectrographs. The amplitude and phase of the principal pulsation mode vary significantly, depending on which line is being measured. The amplitude is observed to be as high as 1000 m s ¹1 in some wavelength bands, despite a previous upper limit of 36 m s ¹1 . Furthermore, some lines are apparently pulsating in anti-phase with others. We suggest this indicates a high-overtone standing wave with a velocity node in the atmosphere of the star.

We present bisector measurements of the H α line of the rapidly oscillating Ap (roAp) star α Cir, obtained from dual‐site observations with medium‐dispersion spectrographs. The velocity amplitude and phase of the principal pulsation mode vary significantly, depending on the height in the H α line, including a phase reversal between the core and the wings of the line. This supports the theory, suggested in Paper I, of a radial pulsational node in the atmosphere of the star. Blending with metal lines partially affects the H α bisector results, but probably not enough to explain the phase reversal. We have also detected changes in the equivalent width of the line during the pulsation, and measured the oscillatory signal as a function of wavelength across the Hα region.

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Within two groups or networks we are trying to build the observational fundamentals for better tests of stellar evolution. The first group is STACC (Small Telescope Array with CCD Cameras) and the second the EU HCM program ANTENA (involving institutes in Spain, France and Denmark).The first information needed is photometric data. Colour-Luminosity diagrams and time series photometry must be obtained. The time series require extensive campaigns in order to give the high quality data needed for asteroseismology. Ideally one should have time series of several quantities (see Balona & Stobie 1979, Mantegazza et al. 1994).The second type of observations is of spectroscopic nature. It is needed to ascertain membership of the stars in a given cluster and to check binarity. Also rotational velocities must be observed to help the attempt to identify the modes in 6 Scuti stars. Finally some information about metallicity and peculiarity is required.