Hosta ‘So Sweet’, a shade-tolerant Asparagaceae species, displays remarkable high-light tolerance in open-field full-sun cultivation without photoinhibition symptoms. To clarify its growing-season photosynthetic dynamics and adaptive strategies, this study measured diurnal photosynthetic variations from May to September, determined chlorophyll fluorescence parameters and pigment contents in May, July and September, and analyzed the data alongside the light and CO2 response curves for July. The results showed that the high temperatures combined with high-light conditions in July lowered Pn relative to May and September, but the light saturation point (LSP) reached 1508.99 μmol m−2 s−1, and the CO2 compensation point (CCP) was 75.46 μmol mol−1, highlighting the robust light energy utilization and carbon assimilation potential. Meanwhile, PSII maximum photochemical efficiency (Fv/Fm) remained stable under these conditions, indicating undamaged photosystems. Mechanistically, its photosynthetic limitation strategies showed seasonal plasticity: a tight coupling between Pn, stomatal conductance, and humidity in May shifted to a strong association between Pn and photoprotective dissipation (qN) in July, followed by an optimization of light capture linked to increased chlorophyll content and adjusted Chl a/b ratios in September. Taken together, H. ‘So Sweet’ synergistically adapts to growing-season light and temperature fluctuations by integrating light utilization potential, photosystem stability and pigment adjustment strategies. This study preliminarily delineated its photosynthetic physiological profile, revealed core light-adaptive strategies, and provided a theoretical basis for the ecological application of this excellent ornamental cultivar.

Abstract We present 1800 multiwavelength Type Ib/c supernovae light-curve models obtained by running the radiation transport code Sedona and varying the mass distribution, velocity profile, and abundance ejecta profiles of helium star progenitors. To create a flexible but physically informed grid, we use autoencoders to construct a representation of ejecta profiles derived from stellar evolution models. We present simulated nearest-neighbor multiband light-curve matches to SN 1994I, SN 2007gr, and iPTF13bvn to demonstrate that realistic light curves can be generated in our grid. We show that the ejecta velocity distribution, in particular, strongly influences the light curve, while variation in 56 Ni mixing alone has a limited impact on the bolometric light curve, even in extreme and unphysical mixing schemes; however, mixing can modestly impact color evolution. Finally, we show that the 56 Ni mass, ejecta mass, and both the magnitude and structure of ejecta velocity distribution can be inferred from the multiband light curves, enabling improved inference over widely used semianalytical models.

Context . The Javalambre VARiability survey (J-VAR) is a multi-filter photometric survey conducted at the Observatorio Astrofísico de Javalambre, covering selected regions of the northern sky, and providing time-domain information for the Javalambre Photometric Local Universe Survey (J-PLUS) fields. J-VAR primarily focuses on small bodies of the Solar System, variable stars, and optical transients. Aims . We aim to present and describe the data set of light curves contained in this first data release of J-VAR. Methods . J-VAR observations were conducted in seven filters observed quasi-simultaneously, three SDSS broad-bands (g, r, and i), and four narrow bands of the J-PLUS filter system (J0395, J0515, J0660, and J0861). As J-VAR is executed primarily in multi-epoch mode, with multiple visits to a given field spread over a period of a year, the data were collected under varying atmospheric and sky brightness conditions. We accounted for these variations by employing an ensemble differential-photometry technique to correct the light curves, which were subsequently calibrated using already available J-PLUS photometry. Additionally, we used a classification scheme based on Bayesian neural networks to select a high-confidence sample of point-like sources (stars and quasi-stellar objects (QSOs)). Results . J-VAR DR1 consists of 101 fields, covering about 200 square degrees on the sky and containing the light curves of more than 1.3 million point-like sources in the seven filters. The light curves span an effective magnitude range from 13 to 19, with a photometric root mean square (RMS) precision of 2% down to a magnitude of ∼16 and 5% to a magnitude of ∼18 in the broad-band filters. Furthermore, we calculated and provide a number of different variability indices for the light curves included in this data release.

Fine-grained space object classification with Convolution-Boosted LSTM using light curves: A new method and a large scale dataset

Hurst index of gamma-ray burst light curves and its statistical study

Multi-model framework for reconstructing gamma-Ray burst light curves

Abstract The Transiting Exoplanet Survey Satellite (TESS) mission has facilitated studies of asteroseismology, eclipsing binaries, and transits in many stars. However, the brightest stars saturate TESS, yet they are the most amenable to photon-hungry high-resolution studies and have long observational histories. In this work, we adapted the halo photometry used in K2 to extract light curves from the unsaturated halo pixels of the star’s point spread function. We used this method to extract light curves for 98 of the brightest stars observed by TESS in Sectors 1–93. These bright stars include 15 red giants, five δ Scuti variables, eight stochastic low-frequency variables, eight eclipsing binaries, and 46 other variables. We measured νmax for 13 red giants using pyMON and Δν for one of them, β Gem (Pollux). For five of them, this represents the first time that oscillations were detected. We derived their stellar masses using the measured νmax and previous interferometric and radiometric angular diameters. We also discovered δ Scuti and γ Doradus variability in α Cep, possible asteroseismic binary signatures in ε Car, and a new eclipsing binary, γ And. Furthermore, we identified 18 stars in our sample that will be observed by the future PLAnetary Transits and Oscillations of stars (PLATO) mission, and 69 stars that have Stellar Observations Network Group (SONG) observations, including some simultaneous with TESS. The light curves are publicly available on the Mikulski Archive for Space Telescopes.

Abstract The intrabinary shocks (IBSs) in spider pulsars emit nonthermal synchrotron X-rays from accelerated electrons and positrons in the shocked pulsar wind, likely energized by magnetic reconnection. The double-peaked X-ray light curves from these shocks have been well characterized in several spider systems. In this paper, we analyze Imaging X-ray Polarimetry Explorer observations of the redback pulsar J1723−2837 to examine the expected synchrotron polarization. Using advanced extraction methods that include spatial, temporal, and particle background weights, we constrain the polarization of the IBS. We compare different models for the magnetic field in the radiation zone and find that the best fit prefers a striped pulsar wind model over other polarized models, with maximum polarization degree of the IBS emission component Π IBS = 3 6 − 15 + 16 % , in addition to an unpolarized non-IBS component. Since this is only 2.4 σ , we cannot claim strong preference over an unpolarized model; we report a 99% confidence level upper limit on the total polarization of both IBS and non-IBS components Π 99 < 36%, which is improved over the 50% limit obtained in previous work. The best-fit polarization of the IBS component is consistent with numerical simulations. Detailed tests of such models are accessible to future measurements.

Transiting extrasolar planets are extraordinarily valuable for understanding the characteristics and formation of planets, because they are the only exoplanets whose physical and orbital properties can be measured to high precision. Thousands are now known, and it is important to maintain a database of them for use by the scientific community. TEPCat performs this task: it is a critical compilation of the physical and observable properties of the known transiting planetary systems. This work introduces the motivation for TEPCat, its scope, contents, and implementation. Example plots of interesting quantities are constructed. The classification of planets and of the eclipse features in their light curves is discussed. TEPCat is maintained and freely available online.

Abstract We present a detailed photometric and spectroscopic analysis of the Type IIP supernova (SN) SN 2023zcu, which exploded in the galaxy NGC 2139 (redshift z = 0.006). SN 2023zcu exhibits a well-sampled light curve covering the rise, plateau, and nebular phases. It has an optically thick phase of 100.6 ± 0.6 days with a magnitude drop of ∼1.7 mag in the V band during the transition between the plateau and nebular phases. Weak emission features in the early-time spectra indicate a low-level interaction between circumstellar material and the SN ejecta. The spectral evolution is well sampled and exhibits a prominent P Cygni profile of H α , a defining characteristic of Type IIP SNe. Signatures of metal-line formation (e.g., Fe ii , Ca ii near-infrared triplet) are also evident in the spectra as the SN evolves. Spectral modeling with the radiative transfer code TARDIS during the early photospheric phase (8.7–35.5 days since explosion) yields photospheric temperatures decreasing from ∼9000 to ∼6000 K and expansion velocities declining from ∼10,000 to ∼5400 km s −1 . A tailored expanding photosphere method fit based on the TARDIS models provides a distance estimate of 27.8 ± 2.0 Mpc. Nebular-phase spectra and bolometric light-curve modeling suggest a progenitor mass in the range 12–15 M ⊙ . This thorough analysis helps to constrain progenitor properties and explosion parameters, thereby strengthening our understanding of Type IIP SNe.

Abstract The TESS space mission has generated an extensive collection of light curves, providing a valuable opportunity to search for solar-like oscillations. Numerous studies have utilized TESS observations to search for solar-like oscillations and achieved excellent results. However, the number of oscillators found by the previous works may be incomplete and significantly below the predicted count. Therefore, we employed a novel method to search for solar-like oscillations. In this work, we utilized TESS 2 minute cadence data to identify solar-like oscillators in the southern ecliptic hemisphere, detecting the presence of oscillations by identifying an excess power hump in the spectrum and combining visual inspection. As a result, we identified 10,548 stars exhibiting solar-like oscillations including 2972 that had not been reported in previous studies. The ν max and Δ ν of oscillators were determined using the fitting and autocorrelation, and the reliability of the Δ ν measurements was further evaluated using the Fourier spectrum of the autocorrelation function. Based on this assessment, 4775 oscillators were classified as having reliable Δ ν , including 1920 that have Δ ν measured for the first time.

Abstract We report the discovery and characterization of a close subdwarf B (sdB) + white dwarf (WD) binary system ------ TYC 3135-86-1. By combining spectroscopy, spectral energy distribution (SED) fitting, and light curve modeling, we determine that the sdB component has an effective temperature of T eff = 22597.10 K, a surface gravity of log g = 4.97, and a mass of M 1 = 0.442 M ⊙ . The system has a short orbital period of P = 0.248895435 days, and the white dwarf companion has a mass of M 2 = 0.658 M ⊙ . The compact configuration of the system is consistent with the formation through common-envelope (CE) ejection. Within this framework, our MESA models suggest a possible scenario in which the sdB component retains a relatively thick hydrogen envelope at the onset of the post-CE phase, in contrast to the typically thinner envelopes of CE-formed sdB stars.

Observations of exoplanetary atmospheres provide critical insights into their chemical composition, formation, and evolution history. Ultra-hot Jupiters serve as excellent targets for atmospheric characterization; studies of these planets may yield key understanding of gas giants' formation and evolution history. We present a thermal emission study of WASP-33,b's dayside atmosphere, based on two secondary eclipse observations with CFHT/WIRCam in two specific narrow band filters, namely the CO and CH4_ ,ppm and 914.3^ _ on filters, and archival data with HST/WFC3 and Spitzer. Stellar pulsations of the host star induce some quasi-periodic photometric variations, particularly in the CH4_ _ on band, which are modeled and corrected in the high-precision differential light curves. An eclipse depth of 1565.2^ +228.6 -237.5 +56.1 -57.0 ,ppm is determined for the CO and CH4_ $= 1.52^ on bands, respectively. Combined with HST/WFC3 and Spitzer data, our joint retrieval of WASP-33 b's dayside atmosphere reveals a high metallicity ( Fe/H +0.35 _ -0.52 $), high C/O ratio (C/O $= 0.78^ +0.03 _ -0.04 $), and a thermal inversion layer, suggesting a formation history involving metal-rich gas accretion. We confirm the presence of the molecules H_2O, H - and CO, and report a tentative detection of TiO in the dayside atmosphere of WASP-33,b. Future higher precision observations with JWST may provide better understanding of constraints on the chemical abundances of oxygen and refractory element abundances to better constrain WASP-33,b's formation and evolutionary pathway.

Abstract 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 multi-color photometric observations, radial velocity measurements, and precise eclipse timings from TESS allow us to constrain the system parameters. The Rømer delay between primary and secondary minima yields a mass ratio of q = 0.299 ± 0.009, enabling robust simultaneous modeling of the light and radial velocity curves with phoebe 2.17. By fixing the albedo of the secondary to its maximum physically plausible value (A2 = 1.0), despite the degeneracy between albedo, surface temperature, and radius, we obtained a satisfactory fit, resulting in a significantly lower temperature (T2 ~ 2360 K) and a radius (R2 ~ 0.16 R⊙) in agreement with literature values. Using the total mass of the components and the orbital size derived from this modeling, we interpret the ETVs and find them best explained by a Jupiter-mass tertiary companion on a ~13-year orbit in all competing models, while the eccentric (e ~0.46) models perform better in terms of fit statistics.

Abstract We present multiwavelength observations of the first recorded low state of the intermediate polar BG CMi. Optical monitoring of the source by members of the American Association of Variable Star Observers reveals a decrease of ∼0.5 mag that lasted ∼50 days in early 2025. During the low state the optical timing properties imply that BG CMi underwent a change in accretion mode, as power at the spin frequency ω dramatically dropped. An XMM-Newton observation revealed a substantial decrease in intrinsic absorption and a slight increase in intrinsic X-ray luminosity, compared to archival Suzaku data. Timing analysis of the X-ray light curves shows that power shifted from the orbital frequency Ω (prominent in Suzaku data) to 2Ω in the low-state XMM-Newton data, along with strengthening of certain orbital sidebands. We suggest that BG CMi transitioned to disk-overflow accretion, where the white dwarf accreted matter via both a disk and a stream, the latter becoming more dominant during the low state due to a decrease in the mass and size of the disk.

Abstract We present a physical characterization of Tsinghua University-Ma Huateng Telescope for Survey (TMTS) J00063798+3104160 (J0006), a rapidly rotating, ultramassive white dwarf (WD) identified in high-cadence light curves from the TMTS. A coherent 23 minute periodicity is detected in TMTS, Transiting Exoplanet Survey Satellite, and Zwicky Transient Facility photometry. A time series of low-resolution spectra with the Keck-I 10 m telescope reveals broad, shallow hydrogen absorption features indicative of an extreme magnetic field and shows no evidence for radial-velocity variations. Atmospheric modeling yields a magnetic field strength of ∼250 MG, while Gaia astrometry and photometry imply a mass of 1.06 ± 0.01 M ⊙ . A significant infrared excess is detected in the Wide-field Infrared Survey Explorer W1 band and is well fitted by a 550 K blackbody, likely arising from residual material of a merger. We interpret the 23 minute photometric modulation as the rotation period of an isolated, massive WD formed likely through the merger of a double WD binary. With one of the shortest rotation periods known among candidate merger remnants and with constraints from a deep Einstein Probe X-ray nondetection, J0006 provides a rare and important observational window into the poorly explored intermediate stages of postmerger evolution.

Abstract Spectroscopic observations of the quasar J0950+5128 spanning 22 yr reveal monotonic radial velocity variations in its broad H β emission line. Moreover, the line profile becomes broader over time, necessitating careful measurements. We present robust H β velocity shift measurements obtained via cross correlation, applied to both the full spectra and to isolated broad H β components derived from spectral decomposition. We also examine the light curves for variability consistent with the spectroscopic trends. Using Lomb–Scargle periodogram analysis, we find no significant periodic signal. We consider several interpretations for the observed changes, including a binary supermassive black hole, dust-cloud obscuration, outflows, a recoiling black hole, and a single perturbed, disk-like broad-line region (BLR). We deem the binary and perturbed BLR scenarios to be physically plausible. The binary interpretation is the only one for which we can immediately compare a physical model to the available data. Thus, we incorporate radial velocity “jitter” to emulate typical quasar variability and fit the radial velocity curve with a Keplerian model to examine whether it can reproduce the observations. In this context, the available observations trace only a segment of the putative orbit. The fit yields a period of 33 yr (observed frame) and an eccentricity of 0.65, with lower limits on the semimajor axis and black hole mass of 10 −2 pc and 10 7 M ⊙ , respectively. Thus, J0950+5128 is a binary candidate deserving further study. The single, perturbed BLR interpretation remains viable but requires additional observations and modeling for further evaluation. Continued monitoring is, therefore, essential.

Abstract Massive red supergiants (RSGs) are known to become hydrodynamically unstable before they explode. Still, the vast majority of supernova (SN) models assume RSG progenitors in hydrostatic equilibrium. Here we follow the hydrodynamic evolution of RSGs with different masses and the development of radial envelope pulsations. Pulsations significantly alter the observable pre- and post-SN properties, and their importance increases substantially as a function of initial mass. We demonstrate that inferring core masses, let alone initial masses, from a single pre-SN luminosity and effective temperature of high-mass RSGs is inadvisable, as these can vary by an order of magnitude during the pulsation. We find that pulsations can naturally lead to “early-excess” emission in SN light curves and to variations in early photospheric velocities, which can help break degeneracies in Type II SNe. We compare to SN 2023ixf and SN 2024ggi, for which pulsating RSG progenitors were reported. We demonstrate that the pre- and post-SN characteristics of SN 2023ixf agree very well with our exploding pulsating RSG model and exhibit meaningful differences from hydrostatic models. The data coverage is insufficient to break all degeneracies. We find insufficient evidence for the claimed pulsation period of the SN 2024ggi progenitor, as it matches Spitzer’s orbital period. This study underscores the importance of hydrodynamical pre-SN stellar models, in particular for massive stars from ≳15 M ⊙ . It implies an important shift in our understanding of the last stages of massive star evolution, the interpretation of pre-SN properties, the connection between SNe and their progenitors, and the missing RSG problem.

Abstract Symbiotic stars are interacting binaries consisting of a red giant and typically a white dwarf, important as potential Type Ia supernova progenitors. Despite theoretical predictions that white dwarfs in symbiotic systems should often be magnetic, direct evidence has been elusive. We report the discovery of a 682.5 ± 7 s periodicity in the XMM-Newton X-ray light curve that we interpret as the spin period of the WD in CH Cygni. This detection provides strong evidence for a magnetic white dwarf in CH Cygni, making it only the second WD symbiotic star with confirmed X-ray pulsations after R Aquarii. Our discovery supports the magnetic propeller model previously proposed for CH Cygni’s jet activity and state transitions.

Abstract A long-lived central engine embedded in expanding supernova ejecta can alter the dynamics and observational signatures of the event, producing an unusually luminous, energetic, and/or rapidly-evolving transient. We use two-dimensional hydrodynamics simulations to study the effect of a central energy source, varying the amount, rate, and isotropy of the energy deposition. We post-process the results with a time-dependent Monte Carlo radiation transport code to extract observational signatures. The engine excavates a bubble at the centre of the ejecta, which becomes Rayleigh-Taylor unstable. Sufficiently powerful engines are able to break through the edge of the bubble and accelerate, shred, and compositionally mix the entire ejecta. The breakout of the engine-driven wind occurs at distinct rupture points, and the outflowing high-velocity gas may eventually give rise to radio emission. The dynamical impact of the engine leads to faster rising optical light curves, with photon escape facilitated by the faster expansion of the ejecta and the opening of low-density channels. For models with strong engines, the spectra are initially hot and featureless, but later evolve to resemble those of broad-line Ic supernovae. Under certain conditions, line emission from ionized, low-velocity material near the centre of the ejecta may be able to escape and produce narrow emission similar to that seen in interacting supernovae. We discuss how variability in the engine energy reservoir and injection rate could give rise to a heterogeneous set of events spanning multiple observational classes, including the fast blue optical transients, broad-line Ic supernovae, and superluminous supernovae.