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\IBVShead{6116}{10 October 2014}

\IBVStitle{New Galactic Double Periodic Variables}

\IBVSauth{Mennickent, R.E.; Rosales, J.}

\IBVSinsto{Astronomy Department, University of Concepci\'on, Concepci\'on, Chile. e-mail: rmennick@udec.cl} %email


\SIMBADobj{V495 Cen}
\SIMBADobj{V4142 Sgr}
\SIMBADobj{TYC 8638-2548-1}
\SIMBADobj{UX Cnc}
\SIMBADobj{TYC 6083-192-1}



\IBVSabs{We discovered two new Double Periodic Variables in the ASAS catalogue of variable stars,}
\IBVSabs{viz., V495~Cen and V4142~Sgr. Other 3 candidates for Double Periodic Variables were found.}
\IBVSabs{All systems have relatively long orbital periods. We present improved ephemerides}
\IBVSabs{ and disentangled light curves.}



\begintext

We have searched the ASAS\footnote{http://www.astrouw.edu.pl/asas/}  catalogue  of semi-detached eclipsing binaries (Pojma\'nski 1997) 
for interacting binaries of the type Double Periodic Variable (DPV). These are intermediate-mass binaries characterized by a long photometric period lasting about 33 times the orbital period (Mennickent et al.\ 2003, 2012a, 2013, Poleski et al.\ 2010). This long periodicity has been interpreted as evidence of mass loss cycles (Mennickent et al.\ 2008, 2012b).  
We performed a visual inspection  of the light curves provided by ASAS, and selected DPV candidates characterized by long-term tendencies in the upper and lower boundaries of the forest of data points.  We determined the orbital and long periods by using the PDM IRAF\footnote{IRAF is distributed by the National Optical Astronomy Observatories,  which are operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.} program (Stellingwerf 1978). Errors for the orbital periods were estimated by visually inspecting the light curves phased with trial periods near the minimum of the periodogram. Then we disentangled the two main photometric frequencies by using a code specially designed for this purpose by Zbigniew Ko{\l}aczkowski. The code adjusts the orbital signal with a Fourier series consisting of the fundamental frequency plus their harmonics. Then it removes this signal from the original time series letting the long periodicity present in a residual light curve. The program fits this remaining signal with another Fourier series consisting of a fundamental frequency and harmonics and removes it. As result we obtain the cleaned light curve with no additional frequencies and two light curves for the isolated orbital and long frequencies. Following this procedure we found two new DPVs and 3 DPV candidates. In the second group the long cycle is observed almost once and it is of low amplitude, so the classification is uncertain. The result of this search is summarized in Tables~1 and 2. The disentangled light curves are shown in Figures~1 and 2.


The two confirmed new DPVs are V495~Cen and V4142~Sgr. They show
a total primary eclipse and have relatively long orbital periods. They are ideal targets for follow-up spectroscopic studies and light curve modeling. All stars in Table\,1 show longer orbital period than those 11 Galactic DPVs reported by Mennickent et al.\ (2012a). For the 
suspected DPVs half of the orbital period was also a possible solution; we followed the ASAS choice, giving a period ratio around 33. 
We checked the WISE image survey\footnote{http://irsa.ipac.caltech.edu/applications/wise/} (Wright et al.\ 2010), especially in the band W4, and find that none of  these targets  show evidence of close nebulosity, which could be relevant when discussing systemic mass loss and evolutionary stage.




\footnotesize
\begin{table}[ht]
\caption{New confirmed Double Periodic Variables and their orbital ($P_{\rm o}$) and long ($P_{\rm l}$) periods. Epochs
for the minimum brightness of the orbital light curve and the maximum brightness of the long-cycle light curve are also given.} 
\vskip 0.2cm
\begin{tabular}{lcrrrrrrr}
\hline 
ASAS-ID &	Other ID&	RA&		DEC& 		$P_{\rm o}$&		$P_{\rm l}$&	T$_{0}$(min$_{\rm o}$)&T$_{0}$(max$_{\rm l}$)&	V (ASAS)\\	
			&		&(2000)&		(2000)&		(days)	&	(days)&	$-$2450000		&$-$2450000 &	(mag)\\	
\hline																
130135$-$5605.5&	V0495 Cen	&	13:01:35 	&$-$56:05:30&	 33.490(18)	&	1283	&	4609.8460   &4894.6	&	9.9	\\
180745$-$2824.1&	V4142 Sgr	&	18:07:45 &	$-$28:24:06&	30.633(27)&		1206	&4726.5550	&3546.7 &		10.95\\	
\hline
\end{tabular}
\label{table1}
\end{table}


\begin{table}[ht]
\caption{New  candidates Double Periodic Variables and their orbital ($P_{\rm o}$) and long ($P_{\rm l}$) periods. Epochs
for the minimum brightness of the orbital light curve and the maximum brightness of the long-cycle light curve are also given. Brightness values are from the ASAS database.} 
\vskip 0.2cm 

\begin{tabular}{lcrrrrrrr}
\hline 

ASAS-ID &	Other ID&	RA&		DEC& 		$P_{\rm o}$&		$P_{\rm l}$&	T$_{0}$(min$_{\rm o}$)&T$_{0}$(max$_{\rm l}$)&	V\\	
			&		&(2000)&		(2000)&		(days)	&	(days)&	$-$2450000		&$-$2450000 &	(mag)\\	
\hline																
090329+0735.7&	UX Cnc		&	09:03:29& 	 07:35:42 &84.761(10) 	&2158: &2715.5975	& 2703.4&		11.75 	\\	
111014$-$2007.1&	TYC 6083-192-1		&11:10:14& 	$-$20:07:06& 	90.386(60) &	3497: &3125.4230	 & 	3799.8	&9.37 		\\
114033$-$5641.8&	TYC 8638-2548-1&		11:40:33& 	$-$56:41:48& 	101.295(22) &	3400:&3423.3300	&2471.0& 		10.51 \\	
\hline
\end{tabular}
\label{table2}
\end{table}
\normalsize
\large

\IBVSfig{7.5cm}{6116-f1.eps}{Disentangled ASAS $V$-band light curves of the new confirmed Double Periodic Variables.}
\IBVSfigKey{6116-f1.eps}{V495 Cen ; V4142 Sgr}{light curve}

\IBVSfig{10cm}{6116-f2.eps}{Disentangled ASAS $V$-band light curves of the new candidate Double Periodic Variables.}
\IBVSfigKey{6116-f2.eps}{TYC 8638-2548-1 ; UX Cnc ; TYC 6083-192-1}{light curve}


\noindent {\bf Acknowledgements:} We acknowledge support by VRID-Enlace 214.016.001-1.0 and the BASAL Centro de Astrof{\'{i}}sica y Tecnolog{\'{i}}as Afines (CATA) PFB--06/2007.\\

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\endreferences 

\IBVSCorrectedVersion{Wed Oct 29 13:24:24 CET 2014}

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