太阳与恒星天体物理

We present a projection method for controlling numerical \(\nabla\cdot\B\) errors in smoothed particle magnetohydrodynamics (SPMHD). The method corrects the magnetic field after an MHD update by solving an elliptic projection problem…

While massive stars are frequently found in triple architectures, the lack of observed parameter distributions has long remained a bottleneck for statistical models of their evolution. We compile the first representative set of physical and…

This study explores multiple aspects of W Ursae Majoris (W UMa) contact binary systems with low mass ratios, providing empirical insights into their definition, structure, rotational stability, and parameter relationships. We first examined…

Stellar radio emission is highly variable with stellar flares lasting from milliseconds to hours. For some stars, their flares or bursts can repeat once every couple of hours, while other stars may flare only once in hundreds of hours of…

Flare ribbons form as a result of energy deposition associated with particles accelerated in low layers of the solar atmosphere. The fine-scale structures of flare ribbons, also called ribbon kernels, offer a potentially powerful diagnostic…

Context: Westerlund 1 (Wd1), the most massive young star cluster in the Milky Way, is an excellent laboratory for studying star formation and early stellar evolution in a starburst-like environment. However, high extinction restricts…

For sixty years, stellar evolutionary models have predicted that intermediate-mass stars slightly contract on the terminal-age main-sequence (TAMS) as they exhaust hydrogen in their convective cores, producing the main-sequence (MS) hook on…

delta Scuti stars are pulsating stars constituting the delta Scuti instability strip in the HR diagram, which consists of A and F stars of various evolutionary stages. They are in the transition region between high-mass hot stars and…

The outer rings (ORs) of Supernova (SN) 1987A were ejected ~20000 years before the explosion. Their characterisation is crucial for constraining the properties of the progenitor of this famous SN. While numerous studies investigated in…

Molecular emission is observed in a wide variety of astrophysical environments, yet a substantial fraction of spectral features detected at mm wavelengths remains unidentified. Identifying these features is essential for constraining the…

Full-disk observations of the Sun in the Ca II K line have been carried out since the late 19th century at various observatories worldwide. These long-term records of solar activity are crucial for reducing discrepancies among solar…

Stars form in molecular clouds under the influence of their local environments, yet the role of massive stellar feedback in either triggering or suppressing star formation remains a fundamental question in astrophysics. The Pillars of…

Aims. Our main aim with this work was to enlarge the pool of open clusters with determined carbon, nitrogen, and oxygen abundances in evolved giants to further advance chemical clocks in stellar age determinations. Methods. High-resolution…

We use Sun-as-a-star helioseismology data, collected by the Birmingham Solar-Oscillations Network (BiSON), to examine the relationship between the solar-cycle-induced frequency shifts of whole-Sun, low-angular degree solar p modes and…

Multiple stellar populations (MPs), characterized by star-to-star light-element abundance variations, are ubiquitous in globular clusters (GCs). Spectroscopy directly reveals these anomalies, while photometric studies, especially with the…

Shadows cast in the cosmic ray (CR) muon sky by the Sun were located using muon data from the MINOS far detector in Northern Minnesota. The shadows were observed independently across three time periods; near solar minimum, near solar…

Metal-poor solar-type stars display a significant reduction in metal-line blanketing at short wavelengths, leading to an excess of near-ultraviolet (NUV) flux compared to their metal-rich counterparts. We utilize GALEX NUV and $\it{Gaia}$…

Massive stars continuously enrich the surrounding interstellar medium by supplying it with stellar material driven by their powerful winds. B supergiant stars (BSGs) in particular are a type of massive star characterized by strong winds and…

The [Ba/Eu] abundance ratio is commonly adopted as a tracer of the relative contributions of the slow (s) and rapid (r) neutron-capture processes. However, at [Fe/H] < -2 dex, Ba can be produced efficiently by both processes, rendering…

We used very long baseline interferometry to constrain the orbit of the binary system 2MASS J05082729-2101444. We observed the system with the VLBA in three epochs at a frequency of 4.85 GHz, which provides an angular resolution of about 3…