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Description
We present a a detailed study of the Double Periodic Variable V4142 Sgr based on photometric and spectroscopic analysis. We re-analized and improved an orbital period of $30.633 \pm 0.002 ~\mathrm{days}$ and a long cycle of $1201 \pm 14 ~\mathrm{days}$. Our spectral analysis reveals H$\alpha$ absorption with a persistent $V \leq R$ asymmetry emission which is considered evidence of a possible wind in the hotspot region. In addition, we find an cold and evolved donor star of $M_\mathrm{d}=1.11 \pm 0.2 ~\mathrm{M_{\odot}}$, $T_\mathrm{d}= 4500 \pm 125 ~\mathrm{K}$ and a $R_\mathrm{d}=19.4 \pm 0.2 ~\mathrm{M_{\odot}}$ and a rejuvenated B-dwarf companion of $M_\mathrm{g}=3.86 \pm 0.3 ~\mathrm{M_{\odot}}$, $T_\mathrm{g}=14380 \pm 700 ~\mathrm{K}$ and $R_\mathrm{g}=6.35 \pm 0.2 ~\mathrm{R_{\odot}}$. The gainer is surrounded by concave and geometrically thick disk creating its own atmosphere around of main component of a radial extension $R_\mathrm{d}= 22.8 \pm 0.3 ~\mathrm{R_{\odot}}$, contributing ~ xx percent of the total luminosity of the system at the $V$-band.The disk is characterized by a hot-spot roughly placed where the stream hits the disk and an additional bright-spot separated $102.\!\!^{\circ}5 \pm 0.\!\!^{\circ}04$ degree apart along the disk edge rim in the direction of the orbital motion. The system is seen under inclination $81.\!\!^{\circ}5 \pm 0.\!\!^{\circ}3$ and to a distance $d=xx \pm xx ~\mathrm{pc}$. Doppler maps of the emission lines reveals sites of enhanced line emission in the 2th and 3th velocity quadrants, the first one corresponds to the hot-spot ad the second to the bright spot detected by the light curve analysis. In addition, the Balner line emission shown a disk with horseshoe-shaped.
