The record-breaking rotational deceleration of the He strong CP star HD 37776 (V901 Ori)

• Název česky: Rekordní rotační brždění He silné chemicky pekuliární hvězdy HD 37776 (V901 Ori)
• Autoři: MIKULÁŠEK Zdeněk; KRTIČKA Jiří; ZVERKO Juraj; HENRY G.W.; JANÍK Jan; ROMANYUK I.I.; ŽIŽNOVSKÝ Jozef; BOŹIČ Hrvoje; ZEJDA Miloslav; GRÁF Tomáš; NETOLICKÝ Martin
• Rok publikování: 2008
• Druh: Článek v odborném periodiku
• Časopis / Zdroj: Contributions of the Astronomical Observatory Skalnaté Pleso
• Fakulta / Pracoviště MU: Přírodovědecká fakulta
• Obor: Astronomie a nebeská mechanika, astrofyzika
• Klíčová slova: stars: chemically peculiar; stars: early type; stars: variables; stars: individual: HD37776; stars: rotation; methods: data analysis
• Popis: We study the long-term light and spectral variations in the He-strong, magnetic chemically peculiar star HD37776 to search for changes of its 1.5387d period in 1976 - 2007. We analyze all published photometric observations and spectrophotometry in the He I 4026 A line. The data were supplemented with 506 new UVB observations obtained during the last 2 observing seasons, 66 estimates of He I equivalent widths on 23 CFHT spectrograms and 69 on Zeeman spectrograms from the 6-m telescope. All the 1895 particular observations have been processed simultaneously. We confirm the previously suspected increase of the period which is a record among CP stars. The mean rate of the period increase during the last 31 years is 0.541+/-0.020 s per year. We interpret this ongoing period increase as the slowing down of the star's surface rotation due to momentum loss through events and processes in its magnetosphere.

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