COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1754

                                 Konkoly Observatory
                                 Budapest
                                 1980 March 5


         SPECTROPHOTOMETRIC OBSERVATIONS OF MIRA CETI


Following an announcement in the IAU Circular No. 3407 by S. McLean, we have
observed the long period variable Mira (o Ceti) on two nights (6 and 18
October 1979) with the help of a scanner attached to the 104-cm reflector of
the Uttar Pradesh State Observatory as a spectral resolution of 50 A. The
monochromatic magnitudes of the star have been corrected for atmospheric
extinction and have been put on an absolute scale corresponding to Hayes and
Latham (1975) calibration of Vega. Table 1 gives these data.

From a plot of these data against wavelength (lambda), classification indices
alpha, beta and gamma (Rautela and Joshi, 1979) were formed. These indices
reveal spectral types of M5.5 III and M4.5 III of the star on the 6th and on
the 18th October 1979, respectively. From a correlation of beat index with
effective temperature, the effective temperatures on the above two nights were
found to be 2470 deg K and 2760 deg K.


S.C. JOSHI,
B.S. RAUTELA
B.B. SANWAL
Uttar Pradesh State Observatory, Naini Tal
263129 India

References:

Hayes, D.S. and Latham, D.W.: 1975, Astrophys.J. 197, 593 [BIBCODE 1975ApJ...197..593H ]
Rautela, B.S. and Joshi, S.C.: 1979, Bull. Astron. Soc. India, 7, 43 [BIBCODE 1979BASI....7...43R ]

Table 1

Monochromatic fluxes of the star Mira Ceti normalized to lambda 555.0 nm

lambda(nm)   6/7 Oct.    18/19 Oct.
             1979        1979
400         +0.63        -
405         +0.50        -
410         +0.49        -
415         +0.50        -
420         +0.57        -
425         +0.63        -
430         +0.66        -
435         +0.67        -
440         +0.71        -
445         +0.79        -
450         +0.83        -
455         +0.84        -
460         +0.81        -
465         +0.83        +1.02
470         +0.79        +1.07
475         +0.68        +0.88
480         +0.64        +0.81
485         +0.63        +0.77
490         +0.44        +0.47
495         +0.24        +0.17
500         +0.31        -0.03
505         +0.45        -0.20
510         +0.17        -0.06
515         +0.00        +0.13
520         -0.06        -0.03
525         +0.02        -0.13
530         -0.07        -0.14
535         -0.08        -0.09
540         -0.18        +0.00
545         -0.17        -0.01
550         -0.09        +0.00
555         +0.00        -0.08
560         +0.01        -0.18
565         +0.05        -0.30
570         -0.05        -0.30
575         -0.16        -0.10
580         -0.26        -0.12
585         -0.28        -0.17
590         -0.07        -0.30
595         -0.02        -0.42
600         -0.14        -0.47
605         -0.37        -0.28
610         -0.51        -0.20
615         -0.60        -0.34
620         -0.54        -0.62
625         -0.33        -0.63
630         -0.46        -0.94
635         -0.75        -1.04
640         -0.96        -1.12
645         -1.13        -1.13
650         -1.37        -0.99
655         -1.32        -0.89
660         -1.32        -0.88
665         -1.27        -0.96
670         -1.13        -1.14
675         -1.02        -1.30
680         -1.10        -1.54
685         -1.32        -1.73
690         -1.51        -1.79
695         -1.82        -1.65
700         -1.92        -1.29
705         -2.10        -1.26
710         -1.96        -1.41
715         -1.70        -1.66
720         -1.49        -1.93
725         -1.66        -2.11
730         -2.01        -2.39
735         -2.47        -2.46
740         -2.73        -2.48
745         -2.81        -2.48
750         -2.83        -2.09