COMMUNICATIONS MITTEILUNGEN
FROM THE DER
KONKOLY OBSERVATORY STERNWARTE
OF THE DER UNGARISCHEN AKADEMIE
HUNGARIAN ACADEMY OF SCIENCES DER WISSENSCHAFTEN
BUDAPEST-SVÁBHEGY

No. 98.

(Vol. 11, Part 5)

UBVRI PHOTOMETRY OF AE URSAE MAIORIS
AT KONKOLY OBSERVATORY (1974-1998)
B. Szeidl, G. Virághalmy

Konkoly Observatory of the Hungarian Academy of Sciences,

1525 Budapest, P.O. Box 67, Hungary

BUDAPEST, 2000

ISBN 963 8361 387
HU ISSN 0238-2091
Felelos kiadó: Balázs Lajos

 

UBVRI PHOTOMETRY OF AE URSAE MAIORIS
AT KONKOLY OBSERVATORY (1974-1998)

 During the years 1974-1998 UBVRI differential photoelectric photometry of the large amplitude Delta Scuti star AE UMa was carried out at Konkoly Observatory and a total of 6575 observations were collected, 1198 in the U, 1947 in the B, 1935 in the V, 784 in the R and 711 in the I colours. The observations are given in Tables 3-7. From the Konkoly photometry 69 new epochs of maximum light were determined. These are listed in Table 2 together with the 59 times of maximum light found in the literature.

INTRODUCTION

The variability of AE Ursae Maioris (=BV92=GC 02998-01063, {alpha}2000=9h36m53s.2, {delta}2000=44o04'00'') was discovered by Geyer et al. (1955). Götz and Wenzel (1961) classified the star's spectral type as A9. Tsesevich (1956) and Filatov (1960) observed the star visually and photographically, but neither of them was able to determine the type and correct value of the period of the variability. Later Tsesevich (1973) observed the star again visually and pointed out that the star belonged to the class of dwarf cepheids and had a period of 0.086017055 day. Tsesevich (1973) reported strong cycle-to-cycle variation of the light curve. He also investigated the star's light variation on old Moscow (Sternberg Institute) archive plates and determined the earliest known epoch of maximum light for the year 1937.

During the past 25 years the star was extensively observed by Broglia and Conconi (1975) and Rodríguez et al. (1992). Several times of maximum light were reported by the BAV group (Braune et al. 1979, 1982; Huebscher et al. 1985, 1992 and Agerer et al. 1999). The results of a new series of CCD measurements were summarized and ten accurate times of maximum light were listed by Hintz et al. (1997). The star was also observed by the Hipparcos (AE UMa=HIP 47181).

In order to investigate the star's light curve variation and its period changes we commenced the observations of AE UMa in 1974 and the first results were published in a short note (Szeidl 1974).

THE OBSERVATIONS

On the whole, 6575 observations have been collected at Konkoly Observatory during 41 nights from 1974 until 1998.

In the years 1974-1977 all the observations were obtained with the 60 cm telescope at Svábhegy near Budapest with the exception of the observations of two nights: 1974 Jan. 14/15=JD. 2442062 and 1974 March 21/22=JD. 2442128. (These observations were made with the 50 cm telescope at Piszkésteto mountain station.) An uncooled UBV photometer was used at the Newtonian focus of the 60 cm telescope. The photometer employed an EMI 9052 B multiplier with Schott filters BG12+GG13 in B and GG11 in V.

Since the night sky near Budapest was too bright, the observations were limited only for the B and V bands.

The observations between 1981-1986 were carried out with the 50 cm Cassegrain telescope at Konkoly Observatory's Piszkésteto mountain station. At this telescope we used an integrating photometer equipped with an unrefrigerated EMI 9058 QB photomultiplier and the following Schott filters: UG2 in U, BG12+GG13 in B and GG11 in V.

In 1996-1998 the observations were made with the 1 m Ritchey-Chrétien telescope of the mountain station. A new photon-counting photometer was used, drawn up and constructed by G. Virághalmy. The EMI 9203 QB type multiplier was electronically cooled to -20±0.1oC. The realized photometric system was close to the Cousins system. The type of filters and their thickness were: 1.5 mm UG1 + 0.8 mm UG5 + 1.5 mm BG38 for the U, 1.8 mm BG13 + 5 mm BG38 + 0.6 mm BG24 for the B, 1.8 mm GG14 + 3 mm BG38 for the V, 4 mm OG1 + 1 mm GG20 + 0.3 mm BG26 for the R and 0.5 mm UG3 + 3.2 mm RG8 + 1.5 mm RG9 for the I band. A detailed description of the photometer is given by Virághalmy (2000).

The star BD+44o1882 was used as comparison, and BD+44o1884 as check star. The brightness (V) and colour (B-V) of these stars are given in Broglia and Conconi (1975).

Several differential photometric observations were carried out between the comparison and the check stars. These runs indicated that the errors of the single observations were less than 0.m01 in B, V and R, and around 0.m02 in U and I on average nights.

The observations of the variable were reduced in the usual way. The UT times have been converted to heliocentric JD. The correction for atmospheric extinction was neglected since the comparison star was very close to the variable. (The distance between them is less then 15'.) The UBV observations have been transformed into the Johnson system in the traditional way. The R and I measurements are in the instrumental system. The journal of the observations is given in Tables 1. The individual observations of AE UMa are listed in Table 3-7 in the sense variable minus comparison.

THE OBSERVED MAXIMA

The light curves have the typical asymmetrical shape of the large amplitude {delta} Scuti stars. The large variation in the amplitude and shape of the light curves makes the determination of the times of light maximum difficult. The observations near the top of the light curves were fitted with third order polinomials and a least squares calculation provided the times of maximum. The results of course, depended on how many data points were involved in the calculation close to maximum light. Therefore several trials were made at each observed maximum. The most reliable results could be achieved when only 5-6 data points were taken into account. This procedure also gave an estimate of the error of the determination of the instant of maximum light: about ± 0.0004 day.

The epochs of maximum light reported here are the mean values obtained from the V and B light curves. (Although a phase lag between the times of maximum light in different colours may exist, this is less than the error of the determination of the epoch of maximum light.)

69 new times of maximum are listed in Table 2, together with those 59 reported in the literature. In Table 2 the O-C values and the epoch numbers are also given calculated by the following ephemeris:

C=2442062.5824+0d.08601707×E

The detector used by the observers (vis=visual, pg=photographic, pe=photoelectric, CCD=CCD photometry) and the source of the data are also indicated in Table 2.

ACKNOWLEDGEMENTS

The authors are indepted to J. Bartus and M.D. Pócs for their help in the preparation of this paper. They are also grateful to Katalin Oláh for making some of the observations. Part of this work was supported by the Hungarian Research Grant OTKA No. T 030955.

REFERENCES

Agerer, F., Dahm, M. and Huebscher, J. 1999, IBVS 4712 (IBVS N°.4712)

Braune, W., Huebscher, J. and Mundry, E. 1979, ANac 300, 165

Braune, W. and Mundry, E. 1982, BAV Mitteilungen Nr. 34

Broglia, P. and Conconi, P. 1975, A&AS 22, 243 (1975A&AS...22..243B)

Filatov, G. S. 1960, Astron. Tsirk. No. 215

Geyer, E., Kippenhahn, R. and Strohmeier, W. 1955, Kleine Veröff. Bamber No. 11

Götz, W. and Wenzel, W. 1961, Mitt. Veränd. Sterne No. 571

Hintz, E. G., Hintz, M. L. and Joner, M. D. 1997, PASP 109, 1073 (1997PASP..109.1073H)

Huebscher, J., Agerer, F. and Wunder, E. 1992, BAV Mitteilungen, Nr. 60

Huebscher, J. Lichtenknecker, D. and Mundry, E. 1985, BAV Mitteilungen Nr. 39

Rodriguez, E., Rolland, A., Lopez de Coca, P., Carcia-Lobo, E. and Sedano, J. L. 1992, A&AS 93, 189 (1992A&AS...93..189R)

Szeidl, B. 1974, IBVS 903 (IBVS N°.903)

Tsesevich, V. P. 1956, Astron. Tsirk. No. 170

Tsesevich, V. P. 1973, Astron. Tsirk. No. 775

Virághalmy, G. 2000, Konkoly Observatory Occasional Technical Notes (to be published)

 

Table 1. Journal of observations

Year Filter No. of nights No. of obs. Length of obs. in hours
1974 V 12 425 24.48

B 12 432 24.50
1975 V 2 53 3.25

B 2 54 3.24
1976 V 5 93 6.55

B 5 97 6.60
1977 V 1 20 1.09

B 1 21 1.09
1981 V 4 264 14.66

B 4 264 14.66

U 3 212 11.89
1982 V 1 15 0.76

B 1 15 0.76

U 1 15 0.76
1983 V 3 203 11.80

B 3 202 11.80

U 3 190 11.48
1986 V 1 67 4.47

B 1 67 4.47

U 1 64 4.47
1996 I 1 48 6.83

R 2 90 10.92

V 2 93 11.21

B 2 93 11.21

U 1 59 7.42
1997 I 3 58 3.94

R 3 60 4.11

V 3 61 4.11

B 3 61 4.11

U 3 42 2.46
1998 I 7 605 47.32

R 7 634 48.57

V 7 641 48.77

B 7 641 48.75

U 7 616 47.74

Table 1. Journal of observations (cont.)

Year Filter No. of nights No. of obs. Length of obs. in hours
All: I 11 711 58.09

R 12 784 63.60

V 41 1935 131.15

B 41 1947 131.16

U 19 1198 86.22

Table 2. Times of maximum of AE UMa

Year Max.time Det. Cycle O-C Source

2400000+



1937 28632.398 pg -156134 +.0048 Tsesevich (1973)
1946 31875.122 pg -118435 -.0287 Filatov (1960)
1950 33379.256 pg -100949 +.0108
1956 35601.188 pg - 75118 +.0359

35604.337 vis - 75081 +.0022 Tesevich (1973)

35607.173 pg - 75048 -.0003 Filatov (1960)
1957 35981.202 pg - 70700 +.0264
1963 38106.402 vis - 45993 +.0027 Tsesevich (1973)
1971 41059.368 vis - 11663 +.0027
1973 41773.223 vis - 3364 +.0020
1974 42062.5832 pe 0 +.0008 Present paper

42065.5959 pe 35 +.0029 Broglia et al. (1975)

42065.6778 pe 36 -.0012

42068.3432 pe 67 -.0023

42068.4302 pe 68 -.0014

42068.5203 pe 69 +.0027

42068.6029 pe 70 -.0007

42068.6871 pe 71 -.0025

Table 2. Times of maximum of AE UMa (cont.)

Year Max.time Det. Cycle O-C Source

2400000+



1974 42069.3808 pe 79 +.0031

42069.4651 pe 80 +.0013

42069.5473 pe 81 -.0025

42069.6363 pe 82 +.0005

42086.4965 pe 278 +.0014

42086.5787 pe 279 -.0025

42069.5473 pe 81 -.0025

42069.6363 pe 82 +.0005

42086.4965 pe 278 +.0014

42086.5787 pe 279 -.0025

42087.4390 pe 289 -.0023

42087.5263 pe 290 -.0011

42087.6155 pe 291 +.0021

42095.5298 pe 383 +.0029 Present paper

42095.6123 pe 384 -.0007

42103.3513 pe 474 -.0032 Broglia et al. (1975)

42106.4523 pe 510 +.0012 Present paper

42119.5252 pe 662 -.0005

42121.5025 pe 685 -.0016

42122.3628 pe 695 -.0015 Broglia et al. (1975)

42122.4484 pe 696 -.0019

42128.2968 pe 764 -.0026 Present paper

42128.3872 pe 765 +.0017

42128.4727 pe 766 +.0012

42128.5557 pe 767 -.0018

42133.4627 pe 824 +.0022

42133.5442 pe 825 -.0023

42134.4055 pe 835 -.0012

42147.3933 pe 986 -.0019

42148.4295 pe 998 +.0021

42148.5117 pe 999 -.0018

42159.4365 pe 1126 -.0011

42161.4145 pe 1149 -.0015

Table 2. Times of maximum of AE UMa (cont.)

Year Max.time Det. Cycle O-C Source

2400000+



1975 42453.5306 pe 4545 +.0006

42453.6137 pe 4546 -.0023

42460.4989 pe 4626 +.0015

42532.407 vis 5462 -.0006 Braune et al. (1979)
1976 42830.6280 pe 8929 -.0008 Present paper

42837.5120 pe 9009 +.0018

42838.4591 pe 9020 +.0027

42866.496 vis 9346 -.0019 Braune et al. (1979)

42869.3377 pe 9379 +.0012 Present paper

42869.4205 pe 9380 -.0020
1977 43162.5708 pe 12788 +.0021
1981 44633.4626 pe 29888 +.0020

44633.5440 pe 29889 -.0026

44633.6309 pe 29890 -.0017

44634.4046 pe 29899 -.0022

44634.4902 pe 29900 -.0026

44634.5810 pe 29901 +.0022

44692.4709 pe 30574 +.0026

44696.343 vis 30619 +.0039 Braune et al. (1982)

44696.426 vis 30620 +.0009

44696.520 vis 30621 +.0089
1983 45355.4902 pe 38282 +.0023 Present paper

45355.5727 pe 38283 -.0012

45382.3228 pe 38594 -.0024

45382.4104 pe 38595 -.0008

45382.4997 pe 38596 +.0025

45382.5807 pe 38597 -.0026
1985 46114.332 vis 47104 +.0015 Huebscher et al. (1985)
1986 46468.4601 pe 51221 -.0026 Present paper

46468.5468 pe 51222 -.0020
1987 46855.6279 pe 55722 +.0023 Rodriguez et al. (1992)

46856.5729 pe 55733 +.0011

46856.6561 pe 55734 -.0017

46857.6017 pe 55745 -.0023

Table 2. Times of maximum of AE UMa (cont.)

Year Max.time Det. Cycle O-C Source

2400000+



1987 46857.6925 pe 55746 +.0025

46858.6382 pe 55757 +.0020

46859.6666 pe 55769 -.0018

46878.4181 pe 55987 -.0020

46878.5064 pe 55988 +.0003

46878.5946 pe 55989 +.0025

46884.5262 pe 56058 -.0011

46884.6117 pe 56059 -.0016

46886.5907 pe 56082 -.0010
1992 48683.317 vis 76970 +.0007 Huebscher et al. (1992)
1996 50151.4564 pe 94038 +.0008 Present paper

50151.5384 pe 94039 -.0032

50152.3170 pe 94048 +.0012

50152.4862 pe 94050 -.0016

50152.5756 pe 94051 +.0017
1997 50458.8815 CCD 97612 +.0009 Hintz et al. (1997)

50458.9636 CCD 97613 -.0031

50459.8240 CCD 97623 -.0028

50459.9113 CCD 97624 -.0015

50467.7388 CCD 97715 -.0016

50467.8236 CCD 97716 -.0028

50490.3607 pe 97978 -.0022 Present paper

50505.6697 CCD 98156 -.0042 Hintz et al. (1997)

50505.7595 CCD 98157 -.0004

50505.8461 CCD 98158 +.0001

50516.7676 CCD 98285 -.0025

50554.4432 pe 98723 -.0024 Present paper
1998 50813.3550 pe 101733 -.0020

50813.4408 pe 101734 -.0022

50813.6151 pe 101736 +.0001

50813.6985 pe 101737 -.0026

50848.4540 pe 102141 +.0021

50848.5391 pe 102142 +.0011

50848.6212 pe 102143 -.0028

Table 2. Times of maximum of AE UMa (cont.)

Year Max.time Det. Cycle O-C Source

2400000+



1998 50849.4815 pe 102153 -.0026

50849.5688 pe 102154 -.0014

50862.3840 pe 102303 -.0027 Agerer et al. (1999)

50872.2809 pe 102418 +.0022 Present paper

50872.3634 pe 102419 -.0013

50872.4481 pe 102420 -.0026

50872.5394 pe 102421 +.0027

50899.3729 pe 102733 -.0012

50899.4570 pe 102734 -.0031

50902.2976 pe 102767 -.0010

50902.3819 pe 102768 -.0028

50903.3321 pe 102779 +.0013

50903.4192 pe 102780 +.0023

50903.5009 pe 102781 -.0020

Table 2. [ASCII text]

Table 3. Differential U observations of AE UMa [ASCII text]

Table 4. Differential B observations of AE UMa [ASCII text]

Table 5. Differential V observations of AE UMa [ASCII text]

Table 6. Differential R observations of AE UMa [ASCII text]

Table 7. Differential I observations of AE UMa [ASCII text]