ISSN 0917-2211

Variable Star Bulletin
No.41

Oct. 2003

First Period Determination of V1899 SgrTaichi Kato
Department of Astronomy, Faculty of Science, Kyoto University
Sakyou-ku, Kyoto 606-8502, Japane-mail: tkato@kusastro.kyoto-u.ac.jp
Received 2003 May. 09
Abstract
We studied the ASAS-3 V -band observations of the supposed RV Tau
star V1899 Sgr. We obtained the likely period of 105.2 d. The observed
characteristics are not inconsistent with the RV Tau-type classi¯cation.

V1899 Sgr (=CoD ¡26± 13240) is registered in General Catalogue of Variable Stars (Kholopov et al. 1985) as an RV Tau star with a photographic rangeof 12.1{14.5. Neither period information was given in the catalogue, nor subsequent study has been published in spite of its brightness. The object is one of
the brightest objects in V band suspected of RV Tau-type variability.
We studied the variability of this object using the ASAS-3 survey data(Pojmanski 2002), and con¯rmed its variability. The V -band light curve constructed from the ASAS-3 public data is presented in Figure 1. The recordedrange of variability in V was 11.6{13.6.
The light curve indicates the presence of »50 d quasi-periodicity. This period is a typical one for an RV Tau-type variable star. Figure 2 shows the Phase
Dispersion Minimization (PDM: Stellingwerf 1978) analysis of the data. Thereare clear periodicity around P » 50 d. There are indications of a double periodicity (2P ), which is consistent with the RV Tau-type variation. By adopting
two strongest period candidates (P = 48:4 d and P = 52:6 d) and folding withthe double period, we obtained the folded light curves in Figure 3.

1

Fig.1 V -band light curve of V1899 Sgr drawn from the ASAS-3 public data.

Fig.2 Period analysis of V1899 Sgr. The strongest signal P = 52:6 d is marked.

2Fig.3 Folded light curves of V1899 Sgr.
Neither of the candidate periods strictly represented the light variation,
which indicates that the variation of V1899 Sgr intrinsically contains some degree of irregularity. While the assumed period 2P = 96:8 d yielded a scattered low-brightness points over a wide range of phases, the assumed period of2P = 105:2 d gives a better and reasonable concentration of these low-brightness
points. This trend re°ects that the ¯rst recorded pulsation (Figure 1) had alarger amplitude than in the later ones. Since some RV Tau stars are known toshow occasional deep primary minima,1 this deep minimum in conjunction withthe minimum phase is in reasonable agreement with the RV Tau-type behavior.
Since the star is recorded conspicuously bright neither in IRAS PSC nor
2MASS public images. This absence of strong infrared excess likely rules out
the possibility of a very cool pulsator or an post-AGB object experiencing aheavy mass-loss.
We are grateful to G. Pojmanski for making the ASAS-3 survey data pub1 See e.g. R Sct: http://www.kusastro.kyoto-u.ac.jp/vsnet/gcvs/SCTR.html

3licly available, and generously allowing us for unlimited usage. This work is
partly supported by a grant-in-aid (13640239, 15037205) from the Japanese
Ministry of Education, Culture, Sports, Science and Technology.

References[1] Kholopov, P. N., Samus', N. N., Frolov, M. S., Goranskij, V. P., Gorynya,N. A., Kireeva, N. N., Kukarkina, N. P., Kurochkin, N. E. et al., 1985, General Catalogue of Variable Stars, fourth edition (Moscow: Nauka PublishingHouse)[2] Pojmanski, G. 2002, Acta Astronomica, 52, 397[3] Stellingwerf, R. F., 1978, ApJ, 224, 953

UW Aqr is a Variable StarTaichi Kato
Department of Astronomy, Faculty of Science, Kyoto University
Sakyou-ku, Kyoto 606-8502, Japane-mail: tkato@kusastro.kyoto-u.ac.jp
Received 2003 May. 10Abstract
We studied the ASAS-3 V -band observations of the CST star UW
Aqr. The object is con¯rmed to be a variable star, likely a semiregularvariable with a period about 220 d.

UW Aqr was reported to be L? type variable star (SVS 2633, 12.0{13.6p)
by Kurochkin (1986). Although Kurochkin (1986) presented a ¯nding chart,
no detailed observations nor description of its variability was reported. Theobject has been registered as \constant" (CST) in the General Catalogue ofVariable Stars (Kholopov et al. 1985).
However, we noticed that the object is identi¯ed with a very red star DO
7714 = IRAS 22040¡0040 = TMSS 00514 = RAFGL 5666S. The IRAS
colors places the object a location where variable stars with young oxygenrich circumstellar shells are populous. We studied variability of this object
using the ASAS-3 survey data (Pojmanski 2002), and con¯rmed that theobject is indeed variable (Figure 1).
The extreme range of variability was V = 10.8{11.8. From the continuously
observed segment of the data, we can put a safer variability range of V =11.3{11.7. In any case, the variability of the object is con¯rmed. From theobserved light curve, the object is more likely a semiregular variable with aperiod about 220 d, rather than an irregular variable as originally proposedby Kurochkin (1986).

4

Fig.1 V -band light curve of UW Aqr drawn fromthe ASAS-3 public data.

We are grateful to G. Pojmanski for making the ASAS-3 survey data publicly available, and generously allowing us for unlimited usage. This work ispartly supported by a grant-in-aid (13640239, 15037205) from the Japanese
Ministry of Education, Culture, Sports, Science and Technology.

References[1] Kholopov, P. N., Samus', N. N., Frolov, M. S., Goranskij, V. P., Gorynya,N. A., Kireeva, N. N., Kukarkina, N. P., Kurochkin, N. E. et al., 1985,
General Catalogue of Variable Stars, fourth edition (Moscow: Nauka
Publishing House)[2] Kurochkin, N. E., 1986, Perem. Zvezdy, 22, 327[3] Pojmanski, G. 2002, Acta Astronomica, 52, 397

ZZ Aqr is a Semiregular Variable Resembling Z UMa
Taichi Kato
Department of Astronomy, Faculty of Science, Kyoto University
Sakyou-ku, Kyoto 606-8502, Japane-mail: tkato@kusastro.kyoto-u.ac.jp
Received 2003 May. 10Abstract
We studied the ASAS-3 V -band observations of the poorly knownvariable star ZZ Aqr. We report that ZZ Aqr is likely an SRB-type variable
resembling Z UMa.

5ZZ Aqr was originally discovered as a variable star by Beljawsky (1928).
The object was rediscovered by Kurochkin (1986); the reported elements were:
L? type, range 12.8{14.1p. Kurochkin (1986) reported that the maxima could
be explained by a period of 168 d, although the period analysis yieled period
candidates of 177 and 72 d. The object has been registered as unclassi¯ed in
the General Catalogue of Variable Stars (Kholopov et al. 1985).
We studied variability of this object using the ASAS-3 survey data (Pojmanski 2002), and con¯rmed that the object is indeed variable (Figure 1).
The range of variability was V = 11.2{12.3. We could con¯rm the 170d periodicity, which corresponds to the longer period reported by Kurochkin(1986). From the observed light curve, the object probably showed alternating
deep and shallow minima (or bright and faint maxima), which was probably
the cause of double periodicity inferred by Kurochkin (1986). Among pulsating
variables with alternating minima, the SRD and RV types would be safely excluded based on the red color of ZZ Aqr (Tycho-2 B ¡ V = +1.7). The lightbehavior resembles that of a rather regular SRB-type variable Z UMa2 with amean period of 195.5 d.

Fig.1 V -band light curve of ZZ Aqr drawn from the ASAS-3 public data.

We are grateful to G. Pojmanski for making the ASAS-3 survey data publicly available, and generously allowing us for unlimited usage. This work ispartly supported by a grant-in-aid (13640239, 15037205) from the Japanese
Ministry of Education, Culture, Sports, Science and Technology.

References[1] Beljawski, S., Astron. Nachr., 294, 41[2] Kholopov, P. N., Samus', N. N., Frolov, M. S., Goranskij, V. P., Gorynya,N. A., Kireeva, N. N., Kukarkina, N. P., Kurochkin, N. E. et al., 1985, General Catalogue of Variable Stars, fourth edition (Moscow: Nauka Publishing
House)
2 e.g. http://www.kusastro.kyoto-u.ac.jp/vsnet/gcvs/UMAZ.html

6

[3] Kurochkin, N. E., 1986, Perem. Zvezdy, 22, 327[4] Pojmanski, G. 2002, Acta Astronomica, 52, 397

VSOLJ
c/o Keiichi Saijo National Science Museum, Ueno-Park, Tokyo Japan
Editor Seiichiro Kiyota
e-mail:skiyota@nias.a®rc.go.jp
Publishing Masahiko Momose

7