太阳与恒星天体物理

We present a comprehensive physical model explaining the origin of Periodic Density Structures (PDS) observed in white-light coronagraphs with characteristic periods of approximately 45, 80, and 120 minutes. Through systematic investigation…

One prominent feature of solar cycle is its irregular variation in its cycle strength, making it challenging to predict the amplitude of the next cycle. Studies show that fluctuations and nonlinearity in generating poloidal field throughout…

The process of the Sun's polar field cancellation reversal commences with the emergence of new cycle Hale's polarity active regions. Once the Sun undergoes polarity reversal, typically occurring near the peak of solar activity, it begins…

Very Long Baseline Interferometry (VLBI) provides high angular resolution images and has been used for stellar astrometry for decades. The DYNAMO-VLBA project utilizes the Very Long Baseline Array (VLBA) to study tight binary and multiple…

The coexistence of PAHs and the C$_{60}$ fullerene in different astrophysical environments can give rise to the formation of new complex species denoted as PAH-C$_{60}$ adducts, which may contribute to the infrared (IR) emission observed.…

FU Ori outbursts are thought to play an important role in stellar assembly and the evolution of protoplanetary disks. However, the progenitor young stellar objects are largely uncharacterized. We obtained a low-resolution optical spectrum…

The atmospheres of massive O-type stars (O stars) are dynamic, turbulent environments resulting from radiatively driven instabilities over the iron bump, located slightly beneath the stellar surface. Here, complex radiation hydrodynamic…

We investigated a volume-limited sample of LAMOST main-sequence stars with masses from 0.25 to 1 $M_{\odot}$ and distances of 150-350 pc to explore how the stellar initial mass function (IMF) varies with metallicity. We corrected the…

Solar filaments are cool and dense plasma structures suspended in the solar corona against gravity. We present observations of a quiescent filament eruption that occurs on 13 July 2015. The eruption is associated with a two-ribbon GOES B8.9…

Dwarf nova (DN) superoutbursts are accompanied by superhumps, which change their periods and profiles over a superoutburst. We present the TESS and ground-based observations of nine WZ Sge-type DNe and candidates in superoutburst. In TCP…

Transport coefficients are calculated for a partially ionized plasma consisting of approximately 90% hydrogen and 10\% helium, representative of a model solar atmosphere with an assumed magnetic field profile. The ion Hall parameter,…

Solar activity is a process driven by many independent but interconnected phenomena. Although the 11-year cycle is the result of operation of the dynamo mechanism, the cause of longer secular variations is not clear. In search of such a…

White Dwarfs (WDs), the final evolutionary stage of most stars, are frequently modeled considering only a dense plasma matter. However, their potential interaction with dark matter (DM), especially in galactic halos where DM is expected to…

In this work, we investigate the structure and gravitational wave (GW) signatures of strongly magnetized, oblate spheroidal quark stars by employing an anisotropic equation of state (EoS) derived from the MIT Bag model, extended to include…

Once per 10,000-100,000 years, an unlucky star may experience a close encounter with a supermassive black hole (SMBH), partially or fully tearing apart the star in an exceedingly brief, bright interaction called a tidal disruption event…

Solar wind, classified by its bulk speed and the Alfv\'enic nature of its fluctuations, generates the heliosphere. The elusive physical processes responsible for the generation of the different types of this wind are a topic of active…

A remarkable span of frontier astrophysics, from gravitational-wave archaeology to the origin of the elements to interpreting snapshots of the earliest galaxies, depends sensitively on our understanding of massive star formation and…

Understanding and predicting solar-cycle variability requires accounting for nonlinear feedbacks that regulate the buildup of the Sun's polar magnetic field. We present a simplified but physically grounded algebraic approach that models the…

We present deep images of the faint nebulosity StDr 90, which we have discovered surrounds the cataclysmic variable (CV) star FY Vulpeculae. Archival photometric and spectroscopic observations, and a new optical spectrum, confirm that FY…

Shocks driven by coronal mass ejections (CMEs) are the most powerful accelerators of gradual solar energetic particles (SEPs) in the inner heliosphere. On 2023 March 13, a halo CME, as seen from the Solar Heliospheric Observatory (SoHO) and…