• DOI:10.1051/0004-6361/200913832
• Corpus ID: 15304415

HR 7355 - another rapidly braking He-strong CP star?

@article{Mikulek2010HR7,
  title={HR 7355 - another rapidly braking He-strong CP star?},
  author={Zdeněk Mikul{\'a}{\vs}ek and Jiř{\'i} Krti{\vc}ka and Gregory W. Henry and S. N. de Villiers and Ernst Paunzen and Miloslav Zejda},
  journal={Astronomy and Astrophysics},
  year={2010},
  volume={511}
}

• Z. Mikulášek, J. Krtička, +3 authors M. Zejda
• Published 1 February 2010
• Physics
• Astronomy and Astrophysics

We acquired 114 new BV observations of HR 7355 at observatories
in Arizona, U.S.A and Cape Town, South Africa. We performed
period analyses of the new observations along with new analyses
of 732 archival measurements from the Hipparcos and ASAS
projects. We find that the light curves of HR 7355; in various
filters are quite similar, double-peaked, with unevenly deep
minima. We substantially refine the rotational period to be P =
0.5214410(4)d, indicating that HR 7355gt; is the most rapidly
rotating CP star known. Our period analyses reveal a possible
lengthening of the rotational period with dP/dt/P = 2.4(8)x10-6
yr-1. We conclude that the shape and amplitude of HR 7355;
light curves are typical of magnetic He-strong CP stars, for
which light variations are the result of photospheric spots on
the surface of a rotating star. We hypothesise that the light
variations are caused mainly by an uneven distribution of
overabundant helium on the star's surface. We discuss the cause
of the rapid rotational braking of the star.