В работе представлены современные результаты исследования магнитного поля химически пекулярных звезд в ассо- циации Орион ОВ1 и в пяти более старых скоплениях. Мы нашли новые доказательства справедливости реликтовой теории происхождения магнитного поля. The paper presents the recent results of the magnetic field mesurements of chemically peculiar stars in the Orion OB1 association and in five older open clusters. We find new evidences of the fossil theory validity of magnetic field origin.

Based on observations with the 6-m SAO RAS telescope, we have found that chemically peculiar star with a large depression of the continuum at A5200 A and strengthened silicon lines in the spectrum has a strong magnetic field. The longitudinal field component Be has a negative polarity and varies from -300 G to -2000 G with a period of 1.756 days. Photometric variations of brightness take place with the same period. We determined the variability of the radial velocity at times of about tens of years pointing to a possible binarity of the object. We have built a magnetic model of this star, determined the inclination angles of the rotation axis to the line of sight i = 20° and of the dipole axis to the rotation axis β = 116°, and the field strength at the pole is Bp = 10 kG. We carried out a chemical composition analysis and found a lack of helium for almost an order of magnitude, some overabundance of silicon and metal elements for more than an order of magnitude, particularly, cobalt for three orders of magnitude.

With the 6-m telescope we performed the magnetic field B e measurements for the chemically peculiar star HD965. During 2000-2015 we obtained over 30 spectra with a Zeeman circular polarization analyzer. The longitudinal field reaches +600 G at the positive extremum and goes below -1300 G at the negative one. The magnetic monitoring of the star shows that the period of B e variability, i.e., the rotation period, exceeds 15 years. Thus, HD 965 belongs to the five slowest rotators among magnetic stars.

We present the results of our new spectropolarimetric observations of FKCom aimed to measure the longitudinal component B z of its magnetic field. The most interesting interpretation of our results suggests that the B z value has significantly decreased compared to the 2008 observations of this star. Such a decrease of the longitudinal component of the magnetic field can be similar to the secular variations of B z registered earlier for another chromospherically active star II Peg. On the other hand, assuming the existence of Bz variations with the rotation phase, we suggest that the variations of the phase curve Bz from 2008 to 2012 originated because of the strengthening of the negative polarity spot, its domination, and as a result-a generally more symmetric distribution of magnetic regions.

This paper presents the results of magnetic field measurements for 39 chemically peculiar and 3 normal main sequence stars used as standard stars. Observations were carried out with the Main Stellar Spectrograph of the Russian 6-m telescope during 2007. Zeeman measurements for 8 stars were performed for the first time. The accuracy analysis for the longitudinal magnetic field measurements of the stars confirms that the systematic errors do not exceed 10-20 G and are within the quoted limits. The absence of significant instrumental deviations follows from the measurements of the CP stars with well-known B e variation curves.

We present the results of a study of the star HD 34736. The spectropolarimetric observations carried out at the 6-m telescope showed the presence of a strong variable longitudinal magnetic field, exceeding -4500 G. The analysis of the Hipparcos photometry gives a set of possible periods of the brightness variability of the star, of which 0 d3603 is preferred. The variable radial velocity of spectral lines of the star and some signatures of lines of at least one other component show that HD 34736 is a binary short-period system. Modeling of the spectra allowed us to estimate the effective temperature T eff of the stars (13 700 and 11500 K) and their projected rotational velocities v sini (73 and >90 kms -1). The analysis of all the available information about the star allows us to hypothesize that the object of study is a close, possibly interacting binary system.

New polarization observations of the subdwarf Bal 09 are analyzed. Bal 09 belongs to the group of hybrid sdB stars, which display both short- and long-period pulsations. Explaining certain properties of Bal 09 that were previously unknown in relation to subdwarfs (variations of the amplitude of the fundamental pulsation mode, rotational splitting of line multiplets and variation of this splitting) requires invoking information about the magnetic field of the star. According to estimates made in 2010, the longitudinal component of the magnetic field of Bal 09 is 34±63 G. This value is significantly lower than the fields found earlier for six other hot subdwarfs. New observational data for the longitudinal magnetic field of Bal 09 was obtained on July 27, 2012, using the main stellar spectrograph of the 6-m telescope of the Special Astrophysical Observatory (SAO). The longitudinal component of the magnetic field 〈B z 〉 was found via a regression analysis. When applied to the star HD 210762 with a zero total magnetic field, this method yielded the value 〈B z 〉 = −12 ± 9 G. The observations also included measurements of 〈B z 〉 for the well-studied magnetic star γ Equ, which is used at the SAO for calibration and testing of the polarimetric instruments. The estimate obtained for γ Equ is 〈B z 〉 = −546±16G, consistentwith the general variations of the longitudinal magnetic-field component of this star. This new study, based on data obtained on July 27, 2012, leads to a similar estimate of the longitudinal magnetic field, 〈B z 〉 = −23±53 G. This estimate of 〈B z 〉 was obtained for the full analyzed spectral range (4400–4958 Å). The corresponding “limited” solution yielded −32±63 G. The regression analysis for the individual spectral sub-bands and for bands containing characteristic spectral features, did not provide firm evidence of the presence of a magnetic field, with a strength exceeding the error in 〈B z 〉. The data analysis leads to the conclusion that the errors of the measurements made in 2010 and 2012 are in good agreement. This testifies to the reliability of the method applied and of the resulting observational material. In addition, the estimates are in good agreement among themselves and with estimates obtained earlier, in 2010. The results unambiguously confirm the earlier conclusion that the subdwarf Bal 09 does not have magnetic field with a strength comparable to those detected earlier for six sdB and sdO stars. Estimates of 〈B z 〉 for hot subdwarfs that have appeared in the literature since the 2010 study also provide trustworthy evidence for the absence of magnetic fields ∼ 1 kG in these objects.