Aims. We provide observational material to study the magnetic field variability of the classical β Cep-type star γ Peg. Methods.The observations were carried out in the He i 6678 line in the course of 23 observing nights from 1997 to 2005 with using the Coudé spectrograph in spectropolarimetric mode at the Crimean 2.6 m telescope. The behavior of stellar wind was studied in the UV region using data from the IUE satellite (the INES database). Results. It is shown that the UV stellar wind exhibits a variability. A variation of the wind due to stellar pulsations has been detected.In the He i 6678 line, the abnormally blueshifted radial velocities (γ = −60.57 ± 0.29 km s −1 ) were detected during a single night in 2005. We do not confirm the 370.5-day orbital period. The most probable orbital period was estimated as P orb = 6.81608±0.00012 day. The ratio P orb /P puls = 44.92 appeared to be very close to integer. We have detected the presence of a weak magnetic field on the star. The longitudinal component of the field varies from -10 G to 30 G with the stellar rotation. The most probable rotational period is P rot = 6.6538 ± 0.0016 days. Both the orbital and the rotational periods are integral multiples of the difference between them: P orb /|P orb − P rot | = 42.002, and P rot /|P orb − P rot | = 41.002. Variation in the longitudinal magnetic field during the pulsation period with an amplitude about 7 G was detected.Key words. stars: magnetic fields -stars: early-type -stars: oscillations -stars: binaries: spectroscopic -stars: individual: γ Pegasi IntroductionThe classical β Cep-type star γ Peg (HD 886, HR 39, Sp B2 IV) exhibits low-order purely radial pulsations. It has one of the weakest amplitude variations in radial velocity 2K = 7 km s −1 , light ∆m v = 0.017 with short pulsation period of 0.15 day, and de Jager et al. (1982) concluded that γ Peg has a virtually zero rotational velocity component; i.e., the star is seen rotation pole-on. pointed out a possibility that the γ-axis of the 0.15-day velocity curve of γ Peg varies. Harmanec et al. (1979) determined the 6.83-day period for the variations in the γ-axis and concluded that the star is a spectroscopic binary with a circular, slightly inclined orbit. Ducatel et al. (1981) also detected the day-to-day variations of the γ-axis, but they suggest that these variations are associated with stellar oscillations.According to analysis of high-resolution observations of this star that were carried out in a period from 1997 to 2005, Butkovskaya et al. (2006 concluded that γ Peg is a spectroscopic binary as suggested by Harmanec et al. (1979). Recently, Chapellier et al. (2006), combining their radial velocity measurements with data from the literature, confirmed the binarity of this star but with another orbital period of 370.5 days.The first attempt to detect a magnetic field on γ Peg was made by Babcock (1958). He found no evidence of a magnetic field in this sharp-line star. Rudy & Kemp (1978) measured theThe radial velocity data are only availabl...

The cycles of activity similar to the solar one are thought to exist in other stars with outer convection zones. The long‐term monitoring of magnetic cycles in stars similar in structure to the Sun is a main diagnostic method for understanding how dynamo generation and amplification of magnetic fields occur. We have performed a search for solar‐like magnetic activity on the yellow subgiant β Aql. Direct measurements of the longitudinal magnetic field of β Aql were performed by measuring the Zeeman splitting in spectral lines, using the circularly polarized spectra obtained at the Crimean Astrophysical Observatory over 51 nights during 1997–2015. The magnetic field on β Aql was detected with the confidence level above 3σ over 24 nights. The activity cycle of β Aql was found to be 969 ± 27 days. We assume that the activity of β Aql is similar to that of stars younger than the Sun. The most probable rotation period was found to be Prot = 5.08697 ± 0.00031 days. Assuming the global magnetic field of β Aql as a dipole, we estimated the polar field strength Bpol = 24 G, the angle between the rotation axis and the line of sight i = 25°, and the angle between the rotation and dipole axes β = 96°.

Over the time of 60 years Vega (α Lyrae = HD 172167, A0V) has been generally accepted as a standard star in the nearinfrared, optical, and ultraviolet regions. But is the spectrophotometric standard Vega really non-variable star? Researchers give very different answers to this question. We aim to search a periodicity in our results of spectropolarimetric study of Vega, namely periodic variations in equivalent width of the spectral lines and longitudinal magnetic field measurements. High-accuracy spectropolarimetric observations of Vega have been performed during 26 nights from 1997 to 2010 using the Coudé spectrograph of the 2.6-m Shain reflector at the Crimean Astrophysical Observatory (CrAO, Ukraine) and during 4 nights in 2007 and 2008 using the echelle spectrograph BOES at the Bohyunsan Optical Astronomy Observatory (BOAO, South Korea). The long-term (year-to-year) variability of Vega was confirmed. It was concluded that this variability does not have magnetic nature.

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