No.35-36

Jan. 2000

ISSN 0917-2211

Variable Star Bulletin
Medium-term variability of FY Per
Tsutomu Watanabe
117 Shirao dormitory , 1414 Oonakazato , Shizuoka , 418-0044 Japan
E-mail: jcc00212@nifty.ne.jp
Hiroyuki Maehara
1-13-4 Namiki , Kawaguchi , Saitama , 332-0034 Japan
E-Mail: mira@cablenet.ne.jp
Received Oct. 23rd, 1999
The light variability of FY Per was discovered by Morgenroth (1936). This
star has been classi¯ed as a cataclysmic variable (Ritter 1990; Zwitter & Munari1994) or a Herbig Ae/Be star (Okazaki 1993). Richter (1964) suggested that
this star varies irregularly. Short-term variability was discussed by Sazonov &Shugarov (1992), who claimed the detection of the 0.064848 d period, howevera more extensive study by Okazaki (1993) could not con¯rm the evidence ofshort period variation. Sazonov & Shugarov (1992) reported that the durationof small outbursts is about 20 d, though more details were obscure.
The authors started intensive monitoring and obtained 140 data from 1996 July(JD 2450290) through 1999 August (JD 2451422). The original data are listed
in Table 1 and the light curve is shown in Figure 1. The smoothed light curve
between JD 2451000 and JD 2451300 which used 2-day means is shown in Figure 2. This light curve demonstrates following characteristics ;(1) The observed magnitude range is 11.0-12.2(2) Two distinct patterns of variability exist:(a) The star is mainly in the bright state, and short declines with 6-8 d duration
are shown; for example JD 2451170 - JD 2451250.
(b) The star is mainly in the faint state, and short outbursts are shown (faintstate duration is equal to or more than bright state duration); for example JD
2451050 - JD 2451150.
(3) Short declines and short outbursts mentioned above occurred quasiperiodically with 20-30 d.
These characteristics seem di®erent from the previously known characteristics
of cataclysmic variables. Further observations are strongly encouraged to get
more detail during the bright state and the faint state.

1

Acknowledgments
I would like to thank Dr.Taichi Kato (Kyoto University) for helpful suggestions
and reading the manuscript..
References
Morgenroth O., 1936, Astron. Nachr., 261, 261
Okazaki A., 1993, Ap & SS, 210, 227
Ritter H., 1990, A & AS, 85, 1179
Sazonov A.V., Shugarov S.YU., 1992, IBVS, 3744 ,1
Zwitter T., Munari U., 1994, A & AS, 107, 503

Figure 1: Light curve of FY Per

Figure 2: Smoothed light curve which used 2-day means

Eclipse period of FN SgrTsutomu Watanabe
117 Shirao dormitory , 1414 Oonakazato , Shizuoka , 418-0044 Japan
E-mail: jcc00212@nifty.ne.jp
Seiichiro Kiyota
1-401-810 Azuma, Tsukuba, 305-0031 Japan
E-mail: skiyota@abr.a®rc.go.jp
Noboru Hasegawa
714-5 Nomura, Hisai, Mie, 514-1113 Japan
Received Dec. 1th, 1999
FN Sgr is a symbiotic star discovered by Ross (1926). Some outbursts
were observed in 1924-26 and in 1936-41 (Beliavsky 1927; Payne 1928; Kenyon
2

Table 1: Observation data of FY Per
JD-2400000
50290.185
50339.210
50383.277
50413.082
50418.150
50425.212
50450.991
50455.927
50467.003
50467.050
50483.997
50492.045
50499.085
50721.202
50730.14250760.973
50761.194
50771.199
50771.217
50785.103
50810.093
50819.218
50832.065
50838.023
50838.968
50848.136
50855.090
50855.938
50879.945
50887.949
51017.247
51048.256
51050.281
51060.156
51061.139
51065.294
51073.132
51073.255
51075.158
51076.165
51082.226
51089.186
51089.208
51090.215
51096.189
51105.115
51109.169

Mag.
12.1
12.0
11.6
11.4
11.4
12.0
11.6
11.7
11.3
11.2
11.3
11.5
11.3
11.2
12.0
11.2
11.0
11.5
11.3
11.3
11.2
11.1
11.2
11.2
11.2
11.1
11.2
11.1
11.1
11.2
11.4
11.9
12.1
11.4
11.5
12.1
12.0
11.7
12.1
12.2
11.6
11.6
11.3
11.3
12.3
12.3
11.8

Obser.
Wnt
Wnt
Mhh
Mhh
Mhh
Wnt
Mhh
Mhh
Mhh
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Wnt
Mhh
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Mhh
Wnt
Mhh
Wnt
Mhh
Mhh
Mhh
Wnt
Wnt
Mhh
Mhh
Wnt

JD-2400000
51109.205
51111.194
51111.236
51119.127
51120.994
51125.096
51125.240
51125.969
51127.131
51128.131
51129.124
51129.216
51130.078
51131.220
51132.994
51135.178
51136.162
51137.106
51137.169
51141.015
51159.165
51165.103
51165.135
51166.162
51168.078
51169.153
51172.167
51173.117
51174.007
51176.269
51177.053
51179.094
51181.112
51184.094
51184.176
51186.141
51187.028
51188.008
51188.099
51189.073
51190.017
51190.158
51191.042
51192.192
51192.990
51194.065
51195.156

Mag.
12.5
11.2
12.0
11.3
11.5
11.8
11.9
11.9
11.9
11.9
12.0
11.9
12.1
11.8
11.9
11.3
11.1
11.2
11.5
11.3
11.8
12.0
11.7
11.6
11.9
11.3
11.5
11.1
11.2
11.1
11.2
12.1
12.2
11.7
11.1
11.2
11.2
11.1
11.3
11.0
11.0
11.4
11.0
11.1
11.4
11.1
11.1

Obser.
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Mhh
Wnt
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Mhh
Wnt
Wnt
Mhh
Wnt
Mhh
Wnt
Wnt
Wnt
Wnt
Mhh
Mhh
Mhh
Wnt
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Mhh
Wnt
Wnt
Mhh
Wnt
Wnt

JD-2400000
51196.101
51197.069
51199.089
51201.064
51205.040
51206.956
51208.113
51208.960
51209.912
51213.965
51216.041
51216.963
51218.041
51219.165
51220.097
51222.058
51222.901
51223.997
51224.074
51225.085
51227.024
51230.023
51230.125
51230.991
51232.024
51233.017
51233.057
51238.044
51241.010
51253.910
51265.976
51298.974
51369.228
51384.267
51390.242
51393.198
51398.290
51399.251
51400.235
51401.281
51402.226
51405.194
51408.158
51411.283
51412.274
51422.271

The magnitudes were estimated against these GSC stars: GSC3355.646(V=11.0), GSC3355.883 (V=11.1), GSC3355.741 (V=11.5), GSC3355.699(V=12.2). Observer code : Mhh (H. Maehara) , Wnt (T. Watanabe) Instrument: 20cm re°ector + visual (H. Maehara), 32cm re°ector + visual (T. Watanabe)
3

Mag.
11.1
11.2
11.1
11.1
11.7
11.2
11.1
11.0
11.1
11.1
11.1
11.3
11.2
11.3
11.1
11.3
11.3
11.5
11.4
11.4
11.3
12.0
11.4
12.2
12.0
12.2
11.8
11.2
11.3
11.4
11.5
11.3
11.4
11.7
11.8
12.0
12.1
12.3
12.3
12.1
12.3
12.3
12.2
12.1
12.1
12.2

Obser.
Wnt
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Mhh
Wnt
Mhh
Wnt
Mhh
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt

Table 1: Eclipse period of symbiotic stars
star
AX Per
CI CygV1329 Cyg
V1413 Aql
FG Serpeirod681.6d855.25d
950d
434d
658d

References
Kenyon 1982
Aller 1954
Grygar, et al. 1979
Wakuda 1988
Munari et al. 1995

1986). Some of symbiotic stars are known to show deep eclipses during outburst.
The period of these stars are listed in Table 1. However, no such obvious
declines were observed in FN Sgr. A new outburst has continued since 1995
(Makiguchi 1995). We VSOLJ members obtained 53 observations from 1995
September through 1999 October which are listed in Table 2. Figure 1 shows
the overall light curve of FN Sgr. Two declines were detected on JD 24450180- JD 24450340 and on JD 2451340 - JD 2451440. An another decline seems tohave occurred near in 1998 February, around the solar conjunction (VSNET light
curve). Therefore, the period of decline of FN Sgr is about 600 d, not about 1200
d. The data were analyzed using the PDMWIN program (Widjajae 1996) which
is based on Phase Dispersion Minimization (PDM) method (Stellingwerf 1978).
The resultant theta diagram is shown in Figure 2. The best determined period is571.5 d. The minimum date in 1999 is analyzed using AVE program (Barverae
1996), and JD 2451403.4 is obtained. As a result, we obtained following element:
Min = JD 2451403.4 + 571.5d * E
The phase-folded light curve using the above element is shown in Figure 3. This
light curve close resembles those of well-known eclipse light curves of symbiotic
stars. Thus, it is almost certain that the detected declines are caused by eclipse.
The duration of eclipse is 0.2 by phase (= 120 d), and the duration of totality
is 0.1 by phase (= 60 d). Multi-colore analysis of FN Sgr in decline is strongly
encouraged.

Figure 1: Overall right curve of FN Sgr
Acknowledgements
This work has been based on VSOLJ Database. We wish to thank the following observers for them valuable observation; M.Moriyama, K.Hirosawa andH.Maehara. We wish to express our sincere gratitude to Dr. Taich Kato, Kyoto
University, who kindly read the manuscript and suggested many improvements.
References
4Figure 2: Theta diagram by PDM analysis

Figure 3: Phase-folded light curve
Table 2: Magnitude estimates of FN Sgr
JD-2400000
49977.944
49979.075
49980.972
49993.939
50003.967
50176.310
50177.285
50177.285
50185.236
50240.155
50254.069
50255.103
50276.134
50286.10650326.996
50329.103
50334.024
50338.000

Mag.
11.6
11.6
11.85V
11.7
11.3
11.9
11.8
11.9
12.0
13.7
13.6
13.4
13.4
13.4
11.8
12.2
11.7
12.04V

Obser.
Hsk
Myy
Kis
Hsk
Has
Has
Has
Has
Has
Has
Kis
Has
Kis
Wnt
Wnt
Myy
Wnt
Kis

JD-2400000
50369.986
50597.188
50624.086
50932.262
50938.219
50981.111
51022.111
51049.046
51066.069
51104.935
51111.915
51132.887
51298.263
51313.199
51340.080
51341.200
51343.160
51367.234

Mag.
11.6
11.1
11.25V
11.2
11.3
10.85V
10.85V
11.2
11.18V
11.5
11.4
11.6
12.07V
11.8
12.11V
12.0
11.95V
12.72V

Obser.
Wnt
Kis
Kis
Wnt
Wnt
Kis
Kis
Wnt
Kis
Wnt
Wnt
Wnt
Kis
Wnt
Kis
Wnt
Kis
Kis

JD-2400000
51369.097
51369.157
51375.128
51383.075
51384.118
51398.983
51402.115
51408.080
51408.131
51421.973
51433.962
51444.990
51444.992
51448.986
51453.938
51460.952
51462.907

Observer code : Has (N.Hasegawa), Hsk (K.Hirosawa), Kis (S.Kiyota), Mhh(H.Maehara), Myy (M.Moriyama), Wnt (T.Watanabe) Magnitude: V:Johnson
V, others:visual
5Mag.
12.58V
12.6
12.92V
13.14V
13.4
13.6
13.6
13.23V
13.7
13.5
12.9
12.0
12.19V
12.17V
12.1
12.0
12.0

Obser.
Kis
Wnt
Kis
Kis
Wnt
Wnt
Wnt
Kis
Wnt
Wnt
Wnt
Mhh
Kis
Kis
Wnt
Wnt
Wnt

Aller,L.,H., 1954, Pub. DAO Victoria, 9, 321
Barverae, R., 1996: http://www.kusastro.kyoto-u.ac.jp/vsnet
Beliavsky,S., 1927, Astr. Nachr., 230, 153
Grygar,J.,H.,L., Chochol,D., and Mammano,A., 1979, Bull. Astr. Inst.
Czech., 30, 8
Kenyon,S.,J., 1982, PASP, 94, 165
Kenyon,s.,j., 1986, The Symbiotic Stars, Cambridge University Press
Makiguchi,N., 1995, in "CV Circular 1995.09 No.34":
ftp://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/VSOLJ/circulars/circ9509.cv
Munari,U., Yudin,B.,F., Kolotilov,E.,A.,and Gilmore,A.,C., 1995, AJ,109, 1740
Payne,C.,H., 1928, Bull. Harv. Coll. Obs., No 861
Ross,F.,E., 1926, AJ, 36, 122
Stellingwerf,R.,F., 1978, ApJ, 224, 953 VSNET light curve:
http://www.kusastro.kyoto-u.ac.jp/vsnet/LCs/index/sgrfn.html
Wakuda,M., 1988, VSOLJ Variable Star Bull., 5, 1
Widjajae,A., 1996: http://www.kusastro.kyoto-u.ac.jp/vsnet

Period revision of ES Del
Tsutomu Watanabe
117 Shirao dormitory , 1414 Oonakazato , Shizuoka , 418-0044 Japan
E-mail : jcc00212@nifty.ne.jp
Mitsutaka Hiraga
19-27 Higasikannonchou , Shimonoseki , Yamaguchi, 752-0906 Japan
Hiroshi Itoh
1001-105 Nishiterakata, Hachiohzi, Tokyo, 192-0153 Japan
Received Jan. 16th, 2000
ES Del (R.A. 20h 43m 58s.41 Dec. +19 ゜ 14' 17".4 (J2000)) is a Mira typevariable, whose period was proposed as 373.9 d (Huth 1956; 1957). However, thecontradiction between this period and the latter observed maximum dates (Halle1974) was pointed out (Kholopov 1986). We obtained 157 visual observations
from 1990 (JD 2448100) through 1999 (JD 24514700) and we observed ¯vemaxima. The light curve is shown in Figure 1. As a result of analysis, 509.6 dperiod was obtained. The best element which satisfying the observed maximum
dates is follows:
Max = JD 2450290 ＋ 509.6 d ｘ E
The observed maximum dates and O-C data calculated using the above newelement are listed in Table 1. The maximum date in 1990 and in 1995 wereobtained by ¯tting their light curves to the light curve in 1996 which closely
resembles them. Seeing the O-C values in Table 1, the period of ES Del issurely 509.6 d now, not 373.9 d. The contradiction between this 509.6 d period
and the former 373.9 d period can be explained by the period change. I willreport on this subject separately (Watanabe 2000).
Acknowledgments This work is based on the VSOLJ database. We wish
to thank Hiroyuki Maehara, Minoru Satoh, Masayuki Moriyama, and Kenji
Hirosawa for their valuable observations.
I would like to thank Dr.Taichi
Kato (Kyoto University) for helpful suggestions and reading the manuscript.
6

Table １：Maximum dates and O-C data
observed maximum
UT1990 December 26
1995 March 1
1996 July 27
1997 December 15
1999 May 11

E
JD
2448252244977824502922450798
2451310

O¡C
-4
-1
0
1
2

0
-2
2
-2
1

References
Halle,E.S., MVS, 1974, 6, H7, 167
Huth,H., MVS, 1956, No.232
Huth,H., VSS, 1957, Band 4, Heft 2, 133
Kholopov,P.N., et al, General Catalogue of Variable Stars 4th Ed., 1986
(Moscow, Nauka)
Watanabe T., 2000, in preparation

Figure 1: Light curve of ES Del from 1990 through 1999
Observer: T.Watanabe (61 obs.), M.Hiraga (45 obs.), H.Itoh (35 obs.),
H.Maehara (8 obs.), M.Satoh (4 obs.), M.Moriyama (3 obs.) and
K.Hirosawa (1 obs.)

Detection of the second historical standstill of HL CMa
Tsutomu Watanabe
117 Shirao dormitory , 1414 Oonakazato , Shizuoka , 418-0044 Japan
E-mail : jcc00212@nifty.ne.jp
Rod Stubbings
19 Greenland Drive, Drouin 3818, Victoria, Australia
E-Mail : stubbo@qedsystems.com.au
Hiroyuki Maehara
1-13-4 Namiki , Kawaguchi , Saitama , 332-0034 Japan
E-Mail : mira@cablenet.ne.jp
Received Jan. 22nd, 2000
7

HL CMa, discovered as the optical counterpart of the hard X-ray source
1E 0643.0-1648 (Chlebowski et al. 1981), is a cataclysmic variable with a mean
outburst cycle around 15 days (Meinunger 1981). This star had been classi¯ed
as a U Gem-type dwarf nova (Patterson 1984). However, with HL CMa's shortrecurrence time and 5 hr orbital period, the possibility that HL CMa may belong
to the Z Cam type of dwarf novae has been suggested (Cannizzo et al. 1988).
The ¯rst obvious standstill which continued for about 40 days, was observed in1982 (cf. Mauche 1987; Kato 1996).
Our observations have detected the second historical standstill beginning inAugust 1999 (JD 2451420). The light curve from January 1999 through January
2000 (JD 2451180 - 2451560), which contains observations from the VSOLJ
Database, is shown in Figure 1. This standstill has already continued for 140
days, showing a longer standstill than the one observed in 1982.
Acknowledgements
We wish to thank the following VSOLJ observers for their valuable observations; Hiroshi Itoh, Susumu Takahashi, Mitsutaka Hiraga, Yasunori Watanabe andTakanori Nishimura. We wish to express our sincere gratitude to Dr. TaichKato, Kyoto University, for helpful suggestions and reading the manuscript.
References
Cannizzo,J.K., Shafter,A.W. and Wheeler,J.C., 1988, ApJ, 333, 227
Chlebowski,T., Halpern,J.P. and Steiner,J.E., 1981, ApJ 247, L35
Kato,T., 1996, vsnet-obs 4216:
http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/obs4000/msg00216.html
Mauche,C.W., Raymond,J.C., 1987, ApJ, 323, 690
Meinunger,L., 1981, IBVS, 2001, 1
Patterson,J., 1984, ApJ Supple., 54, 443

Figure 1: Figure 1 : Light curve of HL CMa
Observer's Observations:R.Stubbings(102 obs.), T.Watanabe(60 obs.),
H.Maehara(38 obs.), H.Itoh(16 obs.), S.Takahashi(6 obs.), M.Hiraga(6 obs.),
Y.Watanabe(1 obs.) and T.Nishimura(1 obs.)

8

EditorSta®

Keiichi
MakotoMasahiko
Seiichiro

Saijo
Watanabe
MomoseKiyotaVSOLJ
c/o Keiichi Saijo
National Science Museum, Ueno-Park, Tokyo Japane-mail:skiyota@abr.a®rc.go.jp (Seiichiro Kiyota)

9