COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1995

                                   Konkoly Observatory
                                   Budapest
                                   1981 July 20

                                   HU ISSN 0374-0676


             INFRARED PHOTOMETRY OF BETA LYRAE


   As part of our on-going program of infrared observations of close-contact
and peculiar binary systems, we have been making photometric observations of
Beta Lyrae since 1977. We are using the 1.3-meter with the "Otto" InSb detector 
at Kitt Peak National Observatory; most of the observations were made
during the day. The beam size was 32"; chopping of 60" was done in declination. 
The standard star for all observations was Alpha Lyrae, whose magnitudes
on the Kitt Peak scale are: J (1.2 microns) = +0.013, H (1.6 microns) = 0.005,
K (2.2 microns) = 0.015, L (3.5 microns) = -0.019, and M (4.6 microns) = -0.045.
Extinction corrections were usually small (<0.01 mag) at all wavelengths. One
observation cycle (standard-source-standard) took about 5 minutes to achieve a
signal-to-noise ratio >=100
   Figures 1-5 summarize the results to date. Statistical errors for each
datum are smaller than the sizes of the symbols, which indicate the year of
observation. Phases were calculated from JD = 2439935.86 + 12.9327 E (Rocznik
Astronomiczny, 1976). Beta Lyrae is known to go though large changes of period
(Kreiner, 1978; Bahyl, 1979); we have not corrected for these changes in our
figures. Despite this, the infrared light curves are remarkably consistent
from year to year.
   Previous infrared observations of Beta Lyrae have been reported by Jameson
and Longmore (1976) and Viotti et al. (1978). Jameson and Longmore's data are
from 1973-1974 and include observations at 8.6 microns. Our observations have
many more data points to more clearly define the shape of the infrared light
curves. Viotti et al. (1978) do not present any light curves but do report
J = 3.28, K = 2.99, L= 2.82, and M = 2.78 at phase 0.14; our values at the same
phase are: J = 3.26, K = 3.06, L = 2.84, and M = 2.68.

  Note that the depth of the primary eclipse decreases relative to the secondary 
eclipse at longer wavelengths. Our data give primary eclipse magnitudes

                             [FIGURE 1]
                             [FIGURE 2]
                             [FIGURE 3]
                             [FIGURE 4]
                             [FIGURE 5]


as: J = 3.84 +- 0.06, H = 3.69 +- 0.07, K = 3.54 +- 0.07, L = 3.23 +- 0.6, and M =
2.90 +- 0.08; and secondary eclipse magnitudes as: J = 3.57 +- 0.09, H = 3.49 +-
0.09, K = 3.36 +- 0.10, L = 3.16 +- 0.08, and M = 2.83 +- 0.09.
   We plan to continue this program in 1981-82 to fill in gaps in the light
curve.



        MICHAEL ZEILIK, PAUL HECKERT, GARY HENSON, PAUL SMITH
                Department of Physics and Astronomy
                   The University of New Mexico
                       Albuquerque, NM 87131
                              U.S.A.



References:
1.Bahyl', V., Pikler, J., and Kreiner, J. M., Acta Astronomica, vol. 29, p.
  393, 1979. [BIBCODE 1979AcA....29..393B ]
2.Jameson, R. F. and Longmore, A. J., Mon. Not. Roy. Astro. Soc., vol. 174,
  p. 217, 1976. [BIBCODE 1976MNRAS.174..217J ]
3.Kreiner, J. M., in Nonstationary Evolution of Close Binaries, A. N. Zytkow
  (editor), p. 133, 1978.
4.Viotti, R., Ferrar-Toniolo, M., Marcocci, M., Natali, G., Persi, P., Spada,
  G., and Saracemo, P., Astronomy and Astrophysics, vol. 62, p. 287, 1978.
  [BIBCODE 1978A&A....62..287V ]