\documentstyle[twoside, epsf]{article}
\input ibvs2.sty

\begin{document}

\IBVShead{4638}{6 October 1998}

\IBVStitletl{CLASSIFICATION OF TY HERCULIS}

\IBVSauth{L. N. Berdnikov}
\IBVSinsto{Sternberg Astronomical Institute, 13 Universitetskij prosp.,
 Moscow 119899, Russia\\ e-mail: berdnik@sai.msu.su}

\SIMBADobj{TY Her}
\IBVStyp{ SRB }
\IBVSkey{}

\begintext

The variability of TY Her was reported by Pickering (1909), who
noted that the star, whose spectrum was M0, had the photographical
peak-to-peak amplitude
of 0.8 mag. 53 visual observations, obtained in 1920-23 by
Zakharov (1953), showed the same amplitude. But later photographic
observations (B\"ohme, 1939; Gaposchkin, 1950; Zinner, 1952)
did not reveal light variations exceeding 0.2 mag, and now this star
is suspected in GCVS-IV as a constant one.

We checked the HIPPARCOS photometric data for TY Her (HIP~81291)
and found that it was not
constant. Figure 1 indicates that the variability is real and there are
slow quasi--periodic light variations within the interval of 0.5 mag.

Both the photometric behavior of TY Her, described above, and its spectrum
show that, most likely, it is a semiregular variable of type SRB.

The research described here was supported in part by the Russian
Foundation of Basic Research and the State Science and Technology
Program ``Astronomy''.
\vskip -5mm

\IBVSfig{5cm}{4638-f1.ps}{}
\vskip -1.2cm
\references

B\"ohme, S., 1939, {\it Astron. Nachr.}, {\bf 268}, 71

Gaposchkin S., 1950, {\it Harv. Ann.}, {\bf 115}, 257

Pickering, E.C., 1909, {\it Astron. Nachr.}, {\bf 179}, 159

Zakharov T.P., 1953, {\it Peremennye Zvezdy}, {\bf 9}, 195

Zinner, E., 1952, {\it Astron. Nachr.}, {\bf 281}, 14

\end{document}


