star | R.A. | Dec. |
(1998.0) | (1998.0) | |
V 781 Tau |
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comparison 1 | 05 50 15 | 26 59 47 |
comparison 2 | 05 50 18 | 26 56 42 |
check | 05 50 13 | 26 56 34 |
The photometric program of the IRAF software is
used to reduce the images. The results of the
reductions show that the difference between the magnitudes of
the check star and the comparison star 1 is
constant within probable errors of
mag for
the V band and
mag for the B band. However, the
difference between the magnitudes of the check star and the
comparison star 2 is
mag for the V band and
mag for the B band. So the star 1 is used as a
comparison star to reduce our observations of V 781
Tau. Extinction corrections are not made because the
comparison star 1 is very close to the variable.
From the observation made during the primary and the secondary eclipses, a mean epoch of the primary minimum light in the B and V bands and that of the secondary minimum light in the B and V bands are derived by means of the parabola fitting. The present times of minima together with those collected from the references are listed in Table 2, where the second column entry denotes the observation method: PG refers to the photographic observations and PHE to the photoelectric one.
JD(hel.) | Meth. | E | (O-C)1 | (O-C)2 | Ref. |
2400000+ | |||||
32881.460 | PG | -31812.5 | -0.0193 | 0.001 | Berthold (1983) |
33950.515 | PG | -28713.0 | -0.0110 | 0.005 | ditto |
34775.368 | PG | -26321.5 | -0.0088 | 0.004 | ditto |
35540.371 | PG | -24103.5 | -0.0149 | -0.004 | ditto |
36610.285 | PG | -21001.5 | -0.0098 | -0.003 | ditto |
36957.442 | PG | -19995.0 | -0.0041 | 0.002 | ditto |
38088.397 | PG | -16716.0 | -0.0071 | -0.003 | ditto |
38440.378 | PG | -15695.5 | -0.0061 | -0.003 | ditto |
39536.327 | PG | -12518.0 | -0.0067 | -0.006 | ditto |
40981.332 | PG | -8328.5 | 0.0003 | -0.000 | ditto |
41329.345 | PG | -7319.5 | -0.0002 | -0.001 | ditto |
41330.381 | PG | -7316.5 | 0.0010 | 0.000 | ditto |
41337.279 | PG | -7296.5 | 0.0008 | -0.000 | ditto |
42839.363 | PG | -2941.5 | 0.0044 | 0.003 | ditto |
43853.9088 | PHE | 0 | -0.0008 | -0.0022 | Cereda et al. (1988) |
43874.9482 | PHE | 61.0 | -0.0009 | -0.0023 | ditto |
44636.339 | PHE | 2268.5 | 0.0024 | 0.0014 | ditto |
44637.371 | PHE | 2271.5 | -0.0003 | -0.0013 | ditto |
46113.4117 | PHE | 6551. | 0.0006 | 0.0010 | Pohl et al. (1987) |
46115.309 | PHE | 6556.5 | 0.0009 | 0.0013 | ditto |
46775.4651 | PHE | 8470.5 | 0.0004 | 0.0018 | Cereda et al. (1988) |
46788.3981 | PHE | 8508.0 | -0.0007 | 0.0007 | ditto |
46798.4005 | PHE | 8537.0 | -0.0006 | 0.0007 | ditto |
46802.3682 | PHE | 8548.5 | 0.0006 | 0.0020 | ditto |
46802.5396 | PHE | 8549.0 | -0.0005 | 0.0009 | ditto |
48268.2285 | PHE | 12798.5 | -0.0041 | 0.0000 | Keskin et al. (1989) |
48268.4014 | PHE | 12799.0 | -0.0036 | 0.0005 | ditto |
48607.2728 | PHE | 13781.5 | -0.0057 | -0.0008 | ditto |
48607.4454 | PHE | 13782.0 | -0.0056 | -0.0007 | ditto |
50814.1688 | PHE | 20180.0 | -0.0125 | -0.0015 | this paper |
50818.1359 | PHE | 20191.5 | -0.0119 | -0.0008 | this paper |
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