Additional photometric and spectroscopic data collected at LNA indicate a probable value of 4.8 hours for its orbital period. The available data, including the historical photometric data of Reinmuth (1925), do not allow a description of the eruptive behaviour of this object, however the spectral signatures presented are common in dwarf novæ in quiescence (see, e.g., Warner 1995 and references therein).
|Figure 1: Spectra of CZ Aql a), OQ Car b,c), V342 Cen d,e,f), ST Cha g,h) and KQ Mon i,j). The fluxes are in units of 10-14 erg cm-2 s-1 Å-1|
Historical photometric data (Kruytbosch 1936) show that the brightness of V342 Cen varies in the range 14.6-16.6 mag with indication of abrupt transitions, as in eruptions. A variation of brightness of 1.7 mag in two consecutive days is seen in our UBVRI measurements, also suggesting an eruption. The same data show the occurrence of two eruptions in 15 days. The presence of a such behaviour indicate V342 Cen as a candidate to dwarf nova class, possibly of U Gem type.
An analysis of the published photometric data of Mauder & Sosna (1975) shows that ST Cha could be an eclipsing variable, with possible values of 6.8 or 9.6 hours for the orbital period. Time series CCD photometry with 7.5 hours of duration in two consecutive nights (March 11/12, 1997) failed to detect any evidence of eclipses with such periods. Our UBVRI photometry shows on the other hand an amplitude of variation of about 2.7 mag (Paper I) while the amplitude quoted in the GCVS4 is mag. Variations of brightness with such amplitudes seem to indicate an eruptive behaviour and suggest a dwarf nova classification for this object.
Our spectra (Figs. 1i and 1j) show a strong blue continuum with H, H and HeI 6678 in emission, contrary to the absorption Balmer lines seen previously (Sion & Guinan 1983, and references therein). H and HeI 6678 are also seen in emission in a spectrum obtained by Zwitter & Munari (1994). KQ Mon is also classified as UX UMa by Downes & Shara (1993) and Zwitter & Munari (1994).
|Figure 2: Spectra of V729 Sgr a), V730 Sgr b), AN Gru c), AY Oct d), V2323 Sgr e,f), SY Vol g), V617 Sgr h), V1082 Sgr in low state i) and in high state j). The fluxes are in units of 10-14 erg cm-2 s-1 Å-1|
The spectroscopic and photometric observations we made for AN Gru and AY Oct did not show the presence of characteristics usually found in cataclysmic variables, like emission lines and UV excess (Figs. 2c and 2d, Paper I). The data show brightness variations in AN Gru consistent with time scales of pulsation of RR Lyræ variables while CCD photometry of AY Oct on three consecutive times, with two days of separation, did not show brightness variation. A possible problem in the correct identification of AY Oct is pointed out by Downes & Shara (1993). Our observations refer to the object indicated in the Hoffmeister's chart (Hoffmeister 1963). Downes et al. (1997) in the 2nd ed. of their cataclysmic variables catalogue mention the presence of a RR Lyræ star 6 east and 6 north of the previous position of AY Oct. It is possible therefore that this RR Lyræ is the only variable in the field.
The star V2323 Sgr was observed spectroscopically on several occasions (see Table 1). Very prominent Balmer emission lines are seen in some spectra superposed on a continuum with very weak TiO absorption bands. In others, the continuum is fainter and of later spectral type, with the TiO bands clearly visible while the emission lines are weak or absent (Figs. 2e and 2f). These data do not confirm V2323 Sgr as cataclysmic since such variables do not display reddened optical continuum or TiO bands which such intensities. Additionally, the emission lines in cataclysmics are broader than the lines seen in this object. On the other hand, a classification as symbiotic star is also improbable since our observations do not reveal emission lines like [OIII] and HeII, whose presence associated with a late spectrum, is characteristic of this class of variables. The true classification of V2323 Sgr is not possible with our data, although the presence of a late spectrum with emission lines is seen in semiregular variables and Miras.
The variable SY Vol was observed spectroscopically on Feb. 12, 1992. The spectrum shows a blue continuum with H in emission (Fig. 2g). Our CCD photometry shows flickering as well as the presence of a brightness variation of 1.8 mag in data separated by 14 days. Such characteristics confirm SY Vol as a cataclysmic variable, probably a dwarf nova. We would like to call attention to a possible problem in the correct identification of this variable in the catalogue of Downes & Shara (1993). The star we observed is the one indicated in the Hoffmeister's chart (Hoffmeister 1963), which is 2.7 west and 19 south from the object marked in the Downes & Shara's chart (see Fig. 6).
Lundström & Stenholm (1984, 1989) have also observed this star. The incompatibility between the distance derived assuming standard intrinsic parameters of W-R stars and the small reddening seen in the direction of WR 109, led those authors to suggest a lower luminosity and indicate a classification of cataclysmic variable or low-mass X-ray binary for V617 Sgr. Our data show the presence of short time scale variability (flickering) and a short orbital period (Steiner et al. 1988). Few objects with spectra like V617 Sgr are known. Among them, V Sge (Herbig et al. 1965; Williams 1983; Echevarría et al. 1989), WX Cen (Diaz & Steiner 1995) and GQ Mus (Krautter & Williams 1989; Diaz & Steiner 1994). Figure 6 shows the finding chart for V617 Sgr.
Published photometric data (Uitterdijk 1949) show that the brightness of V1082 Sgr varies in the range 13.6-15.7 mag. These data also show the occurrence of light changes of 1 mag with time scales of 1-2 days. We propose V1082 Sgr to be a symbiotic star. A finding chart for this object is shown in Fig. 6.
|Figure 3: Spectra of NSV 07105 a,b,c,d), V1003 Oph e), DG CrA f), V499 Ori g), XX Sct h), BN CrA i) and V576 Aql j). The fluxes are in units of 10-14 erg cm-2 s-1 Å-1. The inserted box in Fig. 3d shows a Coudè spectrum of NSV 07105 in the H and HeI 6678 region (this spectrum is not calibrated in flux)|
The star V1003 Oph shows a weak red continuum with emission lines of the Balmer series, HeI (5876, 6678) and H (3968) and K (3934) of CaII (Fig. 3e). The LiI 6707 line in absorption is seen in observations carried out by Quast & Torres (private communication) with the Coudè Spectrograph of the LNA on April 24, 1988. The presence of lines of the Balmer series and CaII in emission and LiI in absorption is characteristic of T Tauri variables (Herbig 1962). Consequently, we classify V1003 Oph as new T Tauri star. This object is listed as IN: in the GCVS4 catalogue, i.e., a probable irregular variable associated with nebulosity.
The other two stars were observed spectroscopically by Gregorio-Hetem et al. (1992) and Torres et al. (1995) in a program aiming to discover new T Tauri stars. Those authors classified DW CMa as Herbig Ae/Be object and DM Ori as T Tauri.
A definitive classification for such objects is not possible with our data. The classification quoted in the GCVS4 for these variables is INS (i.e., a rapid irregular variable associated with nebulosity) for DG CrA, INS: for V499 Ori, IS (i.e., a rapid irregular with no apparent connection with nebulosities) for BN CrA and IS: for XX Sct.
The correct classification of these variables is not obvious since Mira variables as well as red semiregular variables can sometimes present phases in which emission lines are visibles in their spectra. Consequently, more photometric and/or spectroscopic information is necessary in order to better characterize such objects. Some of them showed, however, very late M spectral type and H and Hwith intensities normally found in Mira variables. They are V720 Ara, V814 Ara, V531 Cen, V1257 Sgr, NSV 07097 (see Fig. 4h) and NSV 13052.
|Figure 4: Spectra of KZ Ara a), V514 Ara b), OQ Nor c), OO Pav d), V432 Sco e), V651 CrA f,g), NSV 07097 h), NSV 05443 i) and VV Pav j). The fluxes are in units of 10-14 erg cm-2 s-1 Å-1|
Two of the stars, IK Pup and NSV 03482, show extreme red colours, similar to the NSV 05443 (Paper I). They are, consequently, candidates to carbon stars also. In fact, for IK Pup a C(N) spectral type has been assigned in the GCVS4 while for NSV 03482 we do not have spectroscopic information.
|Figure 5: Spectra of VV Pav a), FH Sct b,c), NSV 06627 d), NSV 06989 e), MU Nor f), HR Nor g), NSV 11826 h), TU Oct i) and V688 Ara j). The fluxes are in units of 10-14 erg cm-2 s-1 Å-1|
The correct classification for those objects is also not possible with our data since several classes of variables can display overlapping spectral types. For example in the range F-K one can find variables like Cephei (Population I Cepheids), W Virginis (Population II Cepheids), RR Liræ, semiregular variables of SRD type (Kholopov et al. 1985) or even the yellow semiregular variables of RV Tauri group. On the other hand, Scuti and RR Liræ objects may present spectral types earlier than F, while semiregular variables of types SRA, SRB and SRC show M spectral type (Kholopov et al. 1985).
As examples of objects better observed we mention BY Aps classified by us as a Mira variable (Cieslinski et al. 1997c), V529 CrA as a probable RV Tauri variable of RVb subgroup (Cieslinski et al. 1998) and NSV 06627 as a RR Lyræ variable of ab sub-type (more information on this star will be published elsewhere).
|Figure 6: Finding charts for CZ Aql, OQ Car, V342 Cen, ST Cha, KQ Mon, V617 Sgr, V729 Sgr, V730 Sgr, V1082 Sgr and SY Vol. The images cover 66 arcmin, with North up and East left|
We are grateful to the CTIO and LNA staffs for the observing assistance during the missions. We thank S.D. Kirhakos, G. Quast and C.A.O. Torres for sharing telescope time and the referee, U. Munari, for his valuable comments and suggestions. D. Cieslinski acknowledges the support of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo).
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