We present an in-depth analysis of the eclipsing binary DD CrB, composed of a B-type subdwarf primary and an M-type main-sequence secondary, with the main goal of investigating its eclipse timing variations (ETVs). Our new multicolour photometric observations, radial velocity measurements, and precise eclipse timings from Transiting Exoplanet Survey Satellite allow us to constrain the system parameters. The R empty set mer delay between primary and secondary minima yields a mass ratio of q = 0 . 299 +/- 0 . 009 , enabling robust simultaneous modelling of the light and radial velocity curves with PHOEBE 2.17. By fixing the albedo of the secondary to its maximum physically plausible value ( A(2) = 1 . 0 ), despite the degeneracy between albedo, surface temperature, and radius, we obtained a satisfactory fit, resulting in a significantly lower temperature ( T-2 similar to 2360 K) and a radius ( R-2 similar to 0 . 16 R-circle dot) in agreement with literature values. Using the total mass of the components and the orbital size derived from this modelling, we interpret the ETVs and find them best explained by a Jupiter-mass tertiary companion on a similar to 13-yr orbit in all competing models, while the eccentric ( e similar to 0 . 46 ) models perform better in terms of fit statistics.

The accretion of matter on a massive white dwarf (WD) can lead to repeated nuclear explosions on its surface over a timescale of years to decades. The seventh explosion of the recurrent symbiotic nova RS Ophiuchi (RS Oph) was recorded on August 8, 2021. In this paper, we examine its early evolution, from 9 hours before its optical maximum until day 42. We achieved our goal by modeling the spectral energy distribution (SED) using optical spectroscopy and simultaneous BVR_ CI_ C photometry, supplemented by JHKL photometry and ultraviolet spectroscopy from previous explosions in 2006 and 1985. Our SED models revealed an early stage of development of the ejecta bipolar structure, consisting of a flared, density-enhanced equatorial disk and low-density regions in bipolar directions. The comparability of the internal shocks' luminosity in the equatorial outflow, inferred from our model parameters, with the luminosity of the warm WD pseudophotosphere during its presence in the spectrum (until ∼day 42) confirmed that a significant part of its radiation originates from reprocessed shock emission. We explain the formation and evolution of the bipolar ejecta structure during RS Oph explosions by the rotation of the accreting WD. Such an ejecta structure provides a natural framework for the generation of strong internal shocks and thus γ-ray emission inside the ejecta.

We present the New Online Database of Symbiotic Variables (NODSV), a comprehensive and publicly accessible catalog of known and candidate symbiotic stars in the Milky Way and nearby galaxies. The database provides an up-to-date census of confirmed symbiotic binaries and systematically compiles information previously scattered across the literature, including photometric and spectroscopic properties, orbital parameters, and characteristics of both their cool and hot stellar components. It further records auxiliary diagnostics such as detected emission lines, flickering, X-ray emission, jets, or information about outburst activity. In its current release, NODSV contains nearly 1 400 objects, classified into confirmed symbiotic stars, three categories of candidates, and misidentified sources. Based on the collected data, though originating from heterogeneous studies, we present a statistical overview of the confirmed symbiotic population, highlighting the distributions of orbital parameters and the properties of the cool giants and their hot companions. Designed as a dynamic and evolving resource, NODSV provides a foundation for future observational campaigns and theoretical investigations of symbiotic binaries.

The VRIC light curves were regularly measured for two eclipsing binaries, NSVS 01031772 and 2MASS J04100497+2931023 as part of our long-term observational project to study low-mass eclipsing binaries with a short orbital period and surface activity. The solution of the Tess light curves in Phoebe results in a detached configuration. Absolute parameters of all components were improved: for N103: M1=0.5475±0.0035 M⊙, R1=0.5297±0.0035 R⊙, M2=0.5038±0.0040 M⊙, R2=0.5217±0.0035 R⊙, for 2M0410: M1=0.639±0.045 M⊙, R1=0.655±0.035 R⊙, M2=0.609±0.045 M⊙, R2=0.631±0.035 R⊙, where the temperatures of the primary components were adopted according to previous studies. The spectral type of the primary components was confirmed to be M4 and K5, and the mass ratio was derived as q=0.920±0.003 or 0.952±0.010, respectively. We propose the presence of a third body in these systems: in the case of N103, a companion with a minimal mass of 50 MJup, orbiting the eclipsing pair with a period of about 19 years, and in 2M0410 a third body with a minimal mass of about 0.1 M⊙ and a short orbital period of about 2.1 years. For N103, the hierarchical structure (2+1)+1 of a possible quadruple system was tested, but its stability was not proven. The characteristics and statistics of the flare events and dark regions on the surface of the components were estimated on the basis of the Tess and our own data. For N103, a mean frequency of flares of one per 40 h was determined. In the case of 2M0410, practically no flares were detected.

Context. Emission-line stars classified as Be exhibit light and colour variability on various timescales, ranging from days to decades. Their evolution must be constrained by long-term observations that are accurately calibrated and stable. Aims. Here, we provide a new reduction of photoelectric UBV observations obtained at the Hvar observatory, spanning more than 50 years (1972–2025). This unique dataset is highly complementary to the Transiting Exoplanet Survey Satellite, which has been conducting observations since 2018, not only in terms of the time baseline, but also in providing fundamental constraints in the U and B bands. Methods. We used new, non-linear reduction equations, with temporally variable extinction over the course of the night, which allowed us to achieve long-term accuracy of 0.008–0.016 mag (1- σ uncertainty), as verified by the Johnson standards. We then classified 59 Be stars into five classes, based on their variability patterns; namely, long-term envelope (LTE), long-term cyclic (LTC), binarity (BIN), rapid low-amplitude (RLA), and long-term quiescence (LTQ). Results. According to our observations, the percentages of stars in the individual classes are 44%, 24%, 25%, 66%, and 19%, respectively. We note that stars in the sample often exhibited more than one pattern. At certain times, changes in the U and B bands were markedly different from those in V (e.g. for BU Tau, V744 Her, V923 Aql, and V1294 Aql). We confirm that the LTE-positive variability is more common than the inverse (20 vs 6); in addition, two stars exhibited both types ( ζ Tau and V1294 Aql). According to our observations, the LTC variability and the LTE-positive variability are almost mutually exclusive. Among 26 binary systems with previously known orbital solutions, circular orbits are more common than eccentric ones (18 vs 8). As for the brightness variations between different quiescent phases, an increasing trend is less common than a decreasing one (4 vs 7); spanning from −6.5 to +6.0 mmag yr −1 . Conclusions. Our observations provide well-calibrated UBV light curves spanning several decades, offering a valuable dataset for investigations of Be-star variability and tests of various models, including the viscous decretion disc model. Continuous monitoring is important for the most interesting objects, namely, β Lyr, EW Lac, δ Sco, γ Cas, and V1294 Aql.

The study of apsidal motion rates in eccentric eclipsing binaries provides an important observational test of theoretical models of stellar structure and evolution. Precise physical parameters of the stellar components together with systematic measurements of the periastron advance are needed. We present new results of our long-term observational project to analyze the apsidal motion in early-type eccentric eclipsing binaries. New ground- and space-based photometric data were obtained, and archival spectroscopic measurements were used in this study of two detached southern hemisphere eclipsing binaries: V1647 Sgr (P = 3(.)(d),e = 0.41), and V2283 Sgr (3(.)(d),47, 0.49). Their TESS observations in four sectors were also included, and the corresponding light curves were solved using the code PHOEBE. The newly completed O - C diagrams were analyzed using all reliable timings found in the literature and calculated using the TESS light curves. New or improved values were obtained for the elements of apsidal motion. Using archival spectroscopy for V1647 Sgr, we improved the precise absolute parameters to M-1 = 2.184(0.035) M-circle dot, M-2 = 1.957(0.035) M-circle dot, and R-1 = 1.839(0.015) R-circle dot, R-2 = 1.716(0.015) R-circle dot. For V2283 Sgr, the absolute dimensions were newly estimated to M-1 = 2.178(0.10) M-circle dot, M-2 = 1.547(0.10) M-circle dot, and R-1 = 1.796(0.01) R-circle dot, R-2 = 1.544(0.01) R-circle dot. We improved relatively long periods of apsidal motion of about 580 and 530 years, together with the corresponding internal structure constants, log k(2), -2.394, and -2.418, for V1647 Sgr and V2283 Sgr, respectively. The relativistic contribution to apsidal motion is not negligible. It is about 12 and 14% of the total rate of apsidal motion for V1647 Sgr and V2283 Sgr, respectively. No signs of an additional body were revealed in the light curves or in the O - C diagrams of the two eccentric systems.

We present an apsidal motion and light curve analysis of the eccentric eclipsing binary V871 Aql, which contains two early-type stars in an eccentric orbit with a short orbital period of 2.95 d. We used the light curve from the Transiting Exoplanet Survey Satellite (Tess), which observed V871 Aql in one sector, to determine its photometric properties and precise orbital ephemeris. The solution of the Tess light curve in PHOEBE results in a detached configuration of two nearly identical components. The temperature of the primary component was fixed to T1 = 14000 +/- 1000 K according to VOSA 7.5, which gives us T2 = 13800 +/- 1000 K for the secondary. The spectral type of the primary component was estimated to be B7, and the photometric mass ratio was derived q similar or equal to 0.99. The preliminary physical parameters of both similar components are M1 = 3.91 +/- 0.40 M ae and M2 = 3.87 +/- 0.40 M ae and R1 = 3.076 +/- 0.03 R ae and R2 = 3.067 +/- 0.03 R ae. The current O-C diagram that spans almost the past 80 years indicates the clear presence of an apsidal motion with a period of about 250 years. No signs of a third body were found in the O-C diagram or in the light-curve solution.

K 1-6 has long been classified as a planetary nebula (PN) hosting a binary central star, yet it has remained poorly studied due to its faintness. The central star exhibits pronounced photometric variability whose origin has so far been unclear. We aim to present a comprehensive characterisation of the K 1-6 system, including the physical properties of its stellar components and the nature of the surrounding nebulosity. We conducted a multi-wavelength analysis combining optical and UV spectroscopy obtained with the Gran Telescopio Canarias, the Telescopio Nazionale Galileo, the Nordic Optical Telescope, and the Hubble Space Telescope. We also present long-term multi-band ground- and space-based photometry, including high-cadence data from the Transiting Exoplanet Survey Satellite, narrow-band imaging, and the latest astrometric constraints from Gaia. Our results show that the nebula is not a remnant PN, but instead consists of interstellar medium photoionised by a hot white dwarf, which is relatively evolved. It has a cooling age of 1-2 Myr, implying that any original PN has long since dissipated. We further find that the central object is a hierarchical triple system, comprising an inner binary with an orbital period likely of the order of thousands of days and a distant tertiary companion on a timescale of tens of thousands of years. The optically dominant cool component of the inner binary is an inflated K-type star displaying extreme magnetic activity, including large-amplitude variability and flaring. Its properties resemble those of BY Dra-type binaries and Abell 35-type systems, and are difficult to reconcile with single-star evolution, pointing instead to a history of binary interaction.

We present a detailed analysis of the low-mass detached eclipsing binary system BB Persei, which contains two K-type stars in a circular orbit with a short period of 0.4856 d. We used light curves from the Transiting Exoplanet Survey Satellite (Tess), which observed BB Per in five sectors, to determine its photometric properties and a precise orbital ephemeris. The solution of the Tess light curve in PHOEBE results in a detached configuration, where the temperature of the primary component was fixed to T1 = 5 300 K according to LAMOsT, which gives us T2 = 5050 +/- 50 K for the secondary. The spectral type of the primary component was derived as K0 and the photometric mass ratio was estimated q = 0.90. Slow period changes on the current O-C diagram spanning the past 25 years indicate the presence of a third body orbiting the eclipsing pair with an orbital period of about 22 years. The companion could be a red dwarf of spectral type M6-M7 with a minimal mass of about 0.1 M ae. The characteristics and temporal variation of the dark region on the surface of the secondary component were estimated.

The results of a two decade long R-band photometric survey of novae in M31 are presented. From these data, R-band light curves have been determined for 180 novae with data sufficient for estimating peak brightness and subsequent rate of decline. The data show a weak correlation of peak brightness with fade rate consistent with the well-known Maximum Magnitude versus Rate of Decline (MMRD) relation. As generally appreciated for Galactic novae, the large scatter in the MMRD relation precludes its use in determining distances to individual novae. The novae at maximum light are distributed with standard deviation σ=0.89 mag about a mean R-band absolute magnitude given by ⟨ M_R ⟩=-7.57±0.07. The overall M31 luminosity distribution is in excellent agreement with that found for Galactic novae suggesting that the nova populations in M31 and the Galaxy are quite similar. The notion that all novae can be characterized by a standard luminosity 15 d after maximum light (M_15) is also explored. Surprisingly, the distribution of M_15 values is characterized by a standard deviation only slightly smaller than that for novae at maximum light and thus offers little promise for precise extragalactic distance determinations. A dozen faint and fast novae that are likely to be previously unidentified recurrent novae have been identified from their position in the MMRD plot and in the M_15 distribution.

The study of apsidal motion in eccentric eclipsing binaries provides an important observational test of theoretical models of stellar structure and evolution. New ground-based and space-based photometric data have been obtained and archival spectroscopic measurements were used in this study of three detached early-type and southern-hemisphere eccentric eclipsing binaries GM Nor (P = 1(d).88, e = 0.05), V397 Pup (3(d).00, 0.30), and PT Vel (1(d).80, 0.12). Their TESS observations in several sectors have also been included and the corresponding light curves were solved using the PHOEBE code. As a result, new accurate photoelectric times of minimum light have been obtained. The newly completed O - C diagrams were analyzed using all reliable timings found in the literature and calculated using the TESS light curves. New or improved values for the elements of apsidal motion were obtained. Using ESO archive spectroscopy, for V397 Pup, the precise absolute parameters were newly derived: M-1 = 3.076(35) M-circle dot, M-2 = 2.306(35) M-circle dot, and R-1 = 2.711(55) R-circle dot, R-2 = 1.680(55) R-circle dot. For PT Vel the absolute dimensions were improved: M-1 = 2.204(25) M-circle dot, M-2 = 1.638(25) M-circle dot, and R-1 = 2.108(30) R-circle dot, R-2 = 1.605(30) R-circle dot. For GM Nor, the less accurate absolute parameters based on the light curve analysis were evaluated: M-1 = 1.94(15) M-circle dot, M-2 = 1.84(14) M-circle dot, and R-1 = 2.27(20) R-circle dot, R-2 = 2.25(20) R-circle dot. We found more precise and relatively short periods of apsidal motion of about 80, 335, and 160 years, along with the corresponding internal structure constants, log k(2), -2.524, -2.361, and -2.563, for GM Nor, V397 Pup, and PT Vel, respectively. Relativistic effects are small but not negligible, making up to 10% of the total apsidal motion rate in all systems. No marks of the presence of the third body were revealed in the light curves, on the O - C diagrams, or in the reduced spectra of the eccentric systems studied here.

We present the discovery of six new triple stellar system candidates composed of an inner eccentric-orbit eclipsing binary with an apsidal motion. These stars were studied using new, precise TESS light curves and a long-term collection of older photometric ground-based data. These data were used for the monitoring of ETVs (eclipse timing variations) and to detect the slow apsidal movements along with additional periodic signals. The systems analysed were ASASSN-V J012214.37+643943.3 (orbital period 2.01156 d, eccentricity 0.15, third body with 3.3 yr period); ASASSN-V J052227.78+345257.6 (2.42673 d, 0.35, 3.2 yr); ASASSN-V J203158.98+410731.4 (2.53109 d, 0.20, 2.7 yr); ASASSN-V J230945.10+605349.3 (2.08957 d, 0.18, 2.3 yr); ASASSN-V J231028.27+590841.8 (2.41767 d, 0.43, 4.9 yr); and NSV 14698 (3.30047 d, 0.147, 0.5 yr). In the system ASASSN-V J230945.10+605349.3, we detected a second eclipsing pair (per 2.99252 d) and found adequate ETV for the pair B, proving its 2+2 bound quadruple nature. All of these detected systems deserve special attention from long-term studies for their three-body dynamics since their outer orbital periods are not too long and because some dynamical effects should be detectable during the next decades. The system NSV 14698 especially seems to be the most interesting from the dynamical point of view due to it having the shortest outer period of the systems we studied, its fast apsidal motion, and its possible orbital changes during the whole 20th century.

Very Large Telescope/UVES spectroscopic and Transiting Exoplanet Survey Satellite (TESS) photometric observations for WASP 0346-21 allow the direct determination of its physical properties, along with the detection of a circumbinary object and oscillating signals. The high-resolution spectra yielded the radial velocities of all three stars and the atmospheric parameters of T eff,A = 7225 +/- 42 K, [M/H] = 0.30 +/- 0.03 dex, and v A sini = 78 +/- 5 km s-1 of the primary component. The combined analysis of these observations resulted in the fundamental parameters of the eclipsing components and the third light of l 3 = 0.043 +/- 0.004, which is consistent with the light contribution of the tertiary star observed in the echelle spectra. WASP 0346-21 A resides within the overlapping main-sequence domain of delta Sct and gamma Dor variables, while the secondary component of M B = 0.185 +/- 0.013 M circle dot, R B = 0.308 +/- 0.023 R circle dot, T eff,B = 10,655 +/- 146 K, and L B = 1.09 +/- 0.17 L circle dot matches well with the low-mass white dwarf (WD) model for Z = 0.01, corresponding to the thick disk population classified by the Galactic kinematics. Multifrequency analyses were performed on the residual TESS data after removing the binarity effects. The low frequencies around 26.348 day-1 and 17.683 day-1 are delta Sct pulsations originating from WASP 0346-21 A, and the high frequencies of 97.996 day-1 and 90.460 day-1 are considered to be extremely low-mass WD oscillations. These results demonstrate that WASP 0346-21 is a hierarchical triple system, consisting of an EL CVn binary with multiperiodic pulsations in each component and a distant outer tertiary.

The results of a two-decade-long R -band photometric survey of novae in M31 are presented. From these data, R -band light curves have been determined for 180 novae with data sufficient for estimating the peak brightness and subsequent rate of decline. The data show a weak correlation of peak brightness with fade rate consistent with the well-known maximum magnitude versus rate of decline (MMRD) relation. As generally appreciated for Galactic novae, the large scatter in the MMRD relation precludes its use in determining distances to individual novae. The novae at maximum light are distributed with standard deviation σ = 0.89 mag about a mean R -band absolute magnitude given by 〈 M _R 〉 = −7.57 ± 0.07. The overall M31 luminosity distribution is in excellent agreement with that found for Galactic novae suggesting that the nova populations in M31 and the Galaxy are quite similar. The notion that all novae can be characterized by a standard luminosity 15 days after maximum light ( M _15 ) is also explored. Surprisingly, the distribution of M _15 values is characterized by a standard deviation only slightly smaller than that for novae at maximum light and thus offers little promise for precise extragalactic distance determinations. A dozen faint and fast novae that are likely to be previously unidentified recurrent novae have been identified from their position in the MMRD plot and in the M _15 distribution.

It is known from archival TESS data that the semi-detached Algol system XZ Ursae Majoris (UMa) is one of the candidate binary stars exhibiting short-period oscillations. We secured new high-resolution spectroscopic observations for the program target to better understand its binary and pulsation properties. From the echelle spectra, the radial velocities (RVs) of the eclipsing pair were derived, and the atmosphere parameters of the primary component were measured to be v(A)sin i = 80 +/- 7 km s(-1), T-eff,T- A = 7940 +/- 120 K, and [M/H] = -0.15 +/- 0.20. The combined solution of our double-lined RVs and the TESS data provides robust physical parameters for XZ UMa with mass and radius measurement precision of better than 2%. The outside-eclipse residuals from a mean light curve in the 0.002 phase bin were used for multifrequency analyses, and we extracted 32 significant frequencies (22 in <5.0 d(-1) and 10 in 39-52 d(-1)). The low frequencies may be mostly aliasing sidelobes, while six of the high frequencies may be pulsation signals arising from the detached primary located inside the delta Sct domain. Their periods, pulsation constants, and pulsational-orbital-period ratios indicate that the mass-accreting primary star is a delta Sct pulsator and, hence, XZ UMa is an oscillating eclipsing Algol.

We report results from the TESS photometric data and new high-resolution spectra of the Algol system X Tri showing short-period pulsations. From the echelle spectra, the radial velocities of the eclipsing pair were measured, and the rotational rate and effective temperature of the primary star were obtained to be v 1 sin i = 84 ± 6 km s −1 and T eff,1 = 7900 ± 110 K, respectively. The synthetic modeling of these observations implies that X Tri is in synchronous rotation and is physically linked to a visual companion TIC 28391715 at a separation of about 6.″5. The absolute parameters of our target star were accurately and directly determined to be M 1 = 2.137 ± 0.018 M ⊙ , M 2 = 1.101 ± 0.010 M ⊙ , R 1 = 1.664 ± 0.010 R ⊙ , R 2 = 1.972 ± 0.010 R ⊙ , L 1 = 9.67 ± 0.55 L ⊙ , and L 2 = 2.16 ± 0.09 L ⊙ . The phase-binned mean light curve was used to remove the binary effect from the observed TESS data. Multifrequency analysis of the residuals revealed 16 significant frequencies, of which the high-frequency signals between 37 day −1 and 48 day −1 can be considered probable pulsation modes. Their oscillation periods of 0.021−0.027 days and pulsation constants of 0.014−0.018 days are typical values of δ Sct variables. The overall results demonstrate that X Tri is an oEA star system consisting of a δ Sct primary and its lobe-filling companion in the semidetached configuration.

ABSTRACT We present a new study of the eclipsing cataclysmic variable SDSS J154453.60+255348.8 to determine the object’s nature and its system parameters together with the probe of the accretion flow structure in the system. Based on analyses of new simultaneous time-resolved photometric and spectroscopic observations of SDSS J154453.60+255348.8 and using our light-curve modelling techniques and the Doppler tomography method, we found that the system contains a white dwarf with the mass of MWD = 0.62(7) M⊙ and an evolved red dwarf as a secondary. The system inclination is close to 90° and the mass ratio is q = 0.49(2). The secondary has an effective temperature T2 = 3400(40) K and a radius about 1.35(15) times larger than a zero-age main-sequence star with similar mass. From observation of the system in high- and low-brightness states, we conclude that SDSS J154453.60+255348.8 is a long-orbital period VY Scl-type system. The accretion disc in the high state is about two times less than the truncation radius, and is completely missing during the low state of the system.

V503 Her was previously proposed as an eclipsing symbiotic candidate based on photometric behavior and spectroscopic appearance indicating the composite optical spectrum. To investigate its nature, we analyzed long-term photometric observations covering 100 yr of its photometric history and new low-resolution optical spectroscopic data, supplemented with the multifrequency measurements collected from several surveys and satellites. Based on the analysis presented in this paper, we claim that V503 Her is not an eclipsing binary star. The optical and infrared wavelengths are dominated by a K-type bright giant with an effective temperature of 4500 K, luminosity of 1900 L _⊙ , and subsolar metallicity on the asymptotic giant branch showing semiregular complex multiperiodic pulsation behavior. V503 Her does not show the characteristics of strongly interacting symbiotic variables, but some pieces of evidence suggest that it could still be one of the “hidden” accreting-only symbiotic systems. However, the currently available data do not allow us to fully confirm or constrain the parameters of a possible companion.

ABSTRACTThe VRC light curves were regularly measured for the eclipsing binary NSVS 7453183 as a part of our long-term observational project for studying of low-mass eclipsing binaries with a short orbital period and surface activity. The TESS light curve solution in phoebe results to the detached configuration, where the temperature of primary component was adopted to T1 = 4300 K according to the SED approximation. It gives us T2 = 4080 ± 100 K for the secondary component. The spectral type of the primary component was estimated to be K6, and the photometric mass ratio was derived q = 0.86. We confirm presence of the third body in this system, a stellar companion with a minimal mass 0.33 M⊙ orbiting the eclipsing pair with a short period about 425 days, and propose the next, fourth body with a longer orbiting period of about 12 years, probably a brown dwarf with the minimal mass of 50 MJup. The hierarchical structure ((1+1)+1) + 1 of this quadruple system is assumed. Characteristics and temporal variations of the dark region on the surface of the primary component were estimated. The average migration speed of about 10° per month was found during years 2020–2022.

We present a new study of the Z~Cam-type eclipsing cataclysmic variable AY~Piscium with the aim of determining the fundamental parameters of the system and the structure of the accretion flow therein. We use time-resolved photometric observations supplemented by spectroscopy in the standstill, to which we applied our light-curve modeling techniques and the Doppler tomography method, to update system parameters. We found that the system has a massive white dwarf $M_{\rm WD}=0.90(4)$ \ms, a mass ratio $q=0.50(3)$, and the effective temperature of a secondary $T_2 = 4100(50)$~K. The system inclination is $i=74.^{\circ}8(7)$. The orbital period of the system $P_{\mathrm{orb}}=0.217320523(8)\;\mathrm{d}$ is continuously increasing with the rate of $\dot{P}_{\mathrm{orb}} = +7.6(5)\times10^{-9}$ d year$^{-1}$. The mass transfer rate varies between 2.4$\times$10$^{-10}$ M$_\odot$ year$^{-1}$ in quiescence up to 1.36$\times$10$^{-8}$ M$_\odot$ year$^{-1}$ in outburst. The accretion disk transitions from the cooler, flared, steady-state disk to a warmer state with a practically constant and relatively high disk height. The mass transfer rate is about 1.6$\times$10$^{-9}$ M$_\odot$ year$^{-1}$ in the standstill. The Balmer emission lines show a multi-component structure similar to that observed in long-orbital-period nova-like systems. Out of standstill, the system exhibits outburst bimodality, with long outbursts being more prominent. We conclude that the Balmer emission lines in AY~Psc are formed by the combination of radiation from the irradiated surface of the secondary, from the outflow zone, and from winds originating in the bright spot and the disk's inner part.