COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                        Number 3313

                                            Konkoly Observatory
                                            Budapest
                                            31 March 1989

                                            HU ISSN 0374 - 0676


                    THREE NEW RED VARIABLES


A continuing nova patrol by Kaiser (MacRobert 1988) has resulted in the
discovery of five variables with maxima brighter than 10.0 m_v,. For
convenient reference, information on all five stars is summarized in Table I.
Observations of DHK 4 have already been reported by Kaiser et al. (1988) and
by Kaiser (1988). DHK 3 will be discussed separately (Williams 1989). This
report presents charts (Figure 1) and information for the remaining three.

                             TABLE I.

Var. Designation    RA (1950)     Dec (1950)   Range         Type    Period
                     h  m  s        o  '  "
DHK 1 = LD 103      01 57 58      +58 03 40    10.0-13.8 v    M       360d
DHK 2               00 36 53      +37 55 32    10.7-11.4 b    SR      375d
DHK 3               05 24 17.0    +23 03 55    10.5-13.0 b    Insb    Irr.
DHK 4= NSV 03005    06 28 47.7    +17 07 08     8.2-10.0 v    EA/GS   1258.56d
DHK 5               03 44 56.8    +50 41 32     9.8-10.7 b    SR      60d

DHK 1 = LD 103

DHK 1 is an independent discovery of a variable reported by Dahlmark (1986).
The star is extremely red. In visual light the maxima are as bright as 10.0m,
but the star is invisible on blue plates reaching to 13.5m. The amplitude
indicates Mira type. Photographic and visual observations by Kaiser and
Baldwin, 1987-1989, and inspection of 23 Harvard red plates, 1967-1980, by
Williams result in the preliminary elements:

                  JD_max=2447220+360d E


                              [FIGURE 1]

 Figure 1. Finding charts for DHK 1, 2, 5, based on yellow-light photos. 
 Faintest stars are ~14m. Labelled stars are: A = BD +57d 456, SAO 022850
 B = BD +57d 451, SAO 022841


The variable is faint on the Palomar Observatory Sky Survey blue print, which
shows a close companion of similar brightness. Observations are needed to
determine which of these two stars is the variable. The finding chart in
Figure 1 is less compressed and more legible than the chart in Dahlmark (1986).


                               [FIGURE 2]

 Figure 2. The semiregular variation of DHK 2, mean cycle length 375 days.

                               [FIGURE 3]

 Figure 3. A compressed light curve of the same data, showing variation 
 of the mean magnitude.


DHK 2=BD +37d112

Observations by Kaiser on 120 Harvard blue plates, 1898-1915, indicate that DHK
2 is a variable of type SR with an amplitude of 0.7m. This variable appears to
be multi-periodic. Recent visual observations by Baldwin suggest that
variations may occur in cycles as short as 70 - 100 days. The plates are not
frequent enough to define individual cycles of this period, but do show a
variation with a mean cycle length of 375 days (Figure 2). A compressed plot
of the same data (Figure 3) shows variation of the mean magnitude with a
possible 3300-day period and 0.3m amplitude.

DHK 5 = BD +50d829 = SAO 024237 = HD 232842 = IRC +50..106

The HD spectral type is M4, while Nassau and Blanco (1954) give M6 and Lahulla
(1987) gives M5. Lahulla also measured the star at +8.51 V. New photoelectric
measures by Williams from JD 2447447 - 569 (Figure 4) show the star varying
from 8.82 - 9.01 V with a cycle length of 60 days.

Observations by Kaiser on 108 Harvard blue plates, 1969-1988, show that the
variable can reach a full amplitude in blue of 0.9m. The plates are not
frequent enough to define individual 60-day cycles but do suggest that
especially bright maxima recur at intervals of about 700 days.

                                [FIGURE 4]

 Figure 4. Photoelectric V measures of DHK 5, showing two cycles of 
 60-day length.


We wish to thank curator Martha Hazen for permission to use the Harvard College
Observatory photographic plate collection and Martin Burkhead, Indiana
University Astronomy Department, for assistance in searching the literature and
examining the Palomar Observatory Sky Survey.


DANIEL H. KAISER         DAVID B. WILLIAMS        MARVIN E. BALDWIN
2631 Washington Street   9270-A Racquetball Way   Route 1
Columbus, IN 47201       Indianapolis, IN 46260   Butlerville, IN 47223
USA                      USA                      USA


REFERENCES

Dahlmark, L., 1986, Inform. Bull. Var. Stars No. 2878.
Kaiser, D.H., Baldwin, M.E., and Williams, D.B., 1988, Inform. Bull. Var. Stars No. 3196.
Kaiser, D.H., 1988, Inform. Bull. Var. Stars No. 3233.
Lahulla, J.F., 1987, Publ. Astron. Soc. Pacific 99, 998. [BIBCODE 1987PASP...99..998L ]
MacRobert, A.M., 1988, Sky and Telescope, 76, 662.
Nassau, J.J., and Blanco, V.M., 1954, Astrophys. J. 120, 118. [BIBCODE 1954ApJ...120..118N ]
Williams, D.B., 1989, Inform. Bull. Var. Stars No. 3314.