aat Acta Astrophys. Tau. Acta Astrophysica Taurica 2712-925X Kiselev Nikolai Nikolaevich, Mosсow, settlement Moskovskii, Tat'yanin Park Str., 12, Moscow, Russia. RU 42 10.34898/aat.vol3.iss2.pp30-38 Magnetism and activity of the Sun and stars – 2021 Conference proceedings Statistics of OBA stars magnetic fields Kholtygin A.F. Mokshin D.N. St. Petersburg State University, Faculty of Mathematics and Mechanics, Stary Peterhof, Universitetsky pr. 28, St. Petersburg 198504, Russia St. Petersburg State University, Faculty of Mathematics and Mechanics, Stary Peterhof, Universitetsky pr. 28, St. Petersburg 198504, Russia 15 06 2022 3 2 30 38 15 06 2022 Copyright (c) Kholtygin A., Mokshin D. Kholtygin A., Mokshin D. The metadata for this submission is licensed under a Creative Commons Attribution 4.0 International License. Copyright and publishing rights for texts published in Acta Astrophysica Taurica is retained by the authors, with first publication rights granted to the journal.Texts are free to use with proper attribution and link to the licensing (Creative Commons Attribution 4.0 International).

Recent measurements of the OBA stars magnetic fields show their magnetic fields to be distributed according to the logarithm-normal law with an average value of log(B) ∼ 2.6−2.8 and a standard deviation of σ ∼ 0.25−0.66, where B is the root-mean-square magnetic field in G. The fraction of OB stars with measured magnetic fields from ∼100 G to ∼50 kG (magnetic OB stars) is 7–12 %. Until recently, no magnetic fields were found in other OBA stars. Improvement of the technique for measuring magnetic fields over the past 5–7 years has made it possible to detect weak magnetic fields in ∼10 BA stars with a B value in the range from 0.2 to ∼15 G. The distribution of the magnetic fields of these weakly magnetic stars can also be described by the log-normal law with the same variance as for magnetic OB stars but with an average log(B) ∼0.10. By analogy with magnetic OBA stars, we assumed that this distribution is valid for all OBA stars with unmeasured magnetic fields. With the radii of these stars we obtain the distribution of magnetic fluxes and magnetic moments of both magnetic and weakly magnetic stars. It is shown that these values for all magnetic OBA stars can be described by common distribution functions. The average magnetic fluxes Φ (in G*cm 2 ) of magnetic and weakly magnetic OB stars are log(Φ) ∼26.3 and ∼23.1, which is close to the corresponding values for magnetars and radio pulsars, respectively. The data obtained allow us to conclude that there is a common distribution for the magnetic fields of all OB stars, both magnetic and weakly magnetic. Such distribution in dependence of a fraction of magnetic stars is presented. The magnetic moments of radio pulsars and magnetars are shown to be 5 orders of magnitude smaller than the corresponding values for weakly magnetic and magnetic stars.

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