太阳与恒星天体物理

Convectively driven motions in the solar photosphere can generate broadband Doppler variability across the chromosphere, transition region and corona. Here we investigate this variability using "Sun-as-a-Star" observations from the Extreme…

We present a collection of eclipse timings of eclipsing binary stars obtained over the extended time interval 2014-2024. In all observations, a DSLR camera was used as the detector. The presented dataset contains 250 previously unpublished…

Observations show that stellar coronal mass ejection (CME) candidates display relatively lower kinetic energies compared to expectations from solar flare-CME relations extrapolated to the stellar regime. This behaviour was predicted by…

Context: Thanks to helioseismology, the rotation profile of the Sun has been measured with great precision down to 20% of its total radius. This rotation profile is used as a calibration to infer the rotation of other stars as well as a…

To date, magnetic fields have been asteroseismically measured in nearly one hundred red giant cores. However, most analyses assume weak magnetic fields and slow rotation so that perturbation theory can be applied. The "traditional…

In this study, we present a catalog of 138 interplanetary coronal mass ejections (ICMEs) identified using multiple distance-normalized ICME criteria within sliding time windows applied to \textit{Solar Orbiter} in-situ measurements. We…

In this work, we investigate eruptive phenomena associated with X-ray flares on AB Doradus using observations from XMM-Newton. Our aim is to detect such events with the help of continuous X-ray absorption. The variation in the hydrogen…

Young open clusters commonly exhibit extended or split upper main sequences, which are widely interpreted as signatures of broad, and in some cases bimodal, stellar rotation distributions. The physical origin of the component commonly…

We present Aditya-L1/VELC spectroscopic observations of 5303{\AA} coronal emission line widths before and after coronal mass ejections (CMEs) which showed coronal dimming. The sit \& stare mode of observations enabled us to study the…

Star-planet interactions (SPIs) describe the continuous exchange of energy, momentum, and mass between exoplanets and their host stars through radiative, tidal, magnetic, and particle-driven processes. Together, these interactions shape the…

Supra-arcade downflows (SADs) are sunward-traveling features routinely observed in hot fan structures above magnetic loop arcades during eruptive solar flares. We manually compiled a catalog (SADCat) of 178 SAD-productive flares imaged by…

The solar coronal magnetic field drives nearly every aspect of solar phenomena and activity -- from flares, coronal mass ejections, and solar wind that governs space weather to the much weaker nanoflares. These magnetic fields are routinely…

We report on the diagnostic inspection of nine Project Hephaistos Dyson Sphere candidate M-dwarfs based on archival data. By comparing the Gaia positions, propagated to the AllWISE epoch, with the mid-infrared centroids measured from the…

The ongoing solar cycle 25 has progressed past its peak of sunspot numbers, being stronger than the previous cycle 24. However, the present polar field is rather weak compared to previous cycles at the same evolution phase, particularly in…

Solar extreme ultraviolet (EUV) irradiance predominantly originates from the chromosphere and corona, and variations in EUV irradiance are a significant driver of space weather at Earth, causing increased satellite drag, radio communication…

The Stellar Observations Network Group (SONG) network has operated for more than a decade, providing long-baseline, high-cadence spectroscopic observations of bright stars and the Sun. The observations, from 2014 through 2025, constitute a…

Recent space-based photometry, particularly from TESS, has opened new possibilities for probing the internal structure of low-mass (LM) helium (He)-core white dwarfs (WDs). We present a homogeneous asteroseismological analysis of six…

Previous studies of $\beta$ Piscis Austrinus (PsA) have speculated that the narrow and saddle-like shapes of some of its weak metallic lines are a consequence of it being a rapidly rotating star viewed nearly pole-on. Here we use the…

Radiative opacity is one of the central microphysical inputs controlling the thermal response of Cepheid envelopes and the driving or damping of radial pulsations. We present a controlled opacity-sensitivity experiment for a fixed delta…

Variations in solar radius (hereafter R_Sun) is a key reference for solar magnetic activity in time. The sunlight amount may have varied with R_Sun and had an effect on the Earth's climate in the past. Eclipse observations offer a unique…