太阳与恒星天体物理

Planets orbiting young, solar-type stars are embedded in a more energetic environment than that of the solar neighbourhood. They experience harsher conditions due to enhanced stellar magnetic activity and wind shaping the secular evolution…

Moreton waves are widely regarded as the chromospheric counterpart of extreme ultraviolet (EUV) waves propagating in the corona. However, direct observational evidence confirming their simultaneous propagation across multiple atmospheric…

Much of the carbonaceous dust observed in the early universe may originate from colliding wind binaries (CWBs) hosting hot, luminous Wolf-Rayet (WR) stars. Downstream of the shock between the stellar winds there exists a suitable…

The Calcium-K line profiles as functions of solar latitude and time were obtained through our observations from the Kodaikanal Solar Observatory using the solar tunnel telescope and spectrograph with a CCD detector. Observations were…

We present the analysis of the extended Main Sequence Turn-Off (eMSTO) in the open cluster NGC\,6067. We derive the projected rotational velocity, \textit{v}sin\textit{i}, of the stars belonging to the eMSTO region of the main sequence (MS)…

Alfv\'en waves are known to be important carriers of magnetic energy that could play a role in coronal heating and/or solar wind acceleration. As these waves are efficient energy carriers, how they are dissipated still remains one of the…

The filamentary dark cloud complex in Norma reveals signs of active low-mass star formation including protostars, H-alpha emission line stars, Herbig Haro objects, and the eruptive FU Orionis-like star V346 Nor. We present results of the…

The star NGC 3603-A1 has long been known to be a very massive binary, consisting of a pair of O2-3If*/WN5-6 stars, which show Wolf-Rayet-like emission due to their luminosities being near the Eddington limit. The system has been poorly…

We present a radial velocity (RV) survey of the field OB and OBe stars of the SMC Wing. We use multi-epoch observations of 55 targets obtained with the Magellan IMACS and M2FS multi-object spectrographs to identify single- and double-lined…

Mass drainage is frequently observed in solar filaments. During filament eruptions, falling material most likely flows along magnetic field lines, which may provide important clues for the magnetic structures of filaments. Here we study…

We present an updated atlas of spectra from the Low-Resolution Spectrometer (LRS) on the Infrared Astronomical Satellite (IRAS), which took spectra from 7.67 to 22.73 um with a spectral resolving power (lambda / Delta lambda) of 20-60. The…

Double white dwarf binaries are an important remnant of binary evolution as they are possible type Ia supernova progenitors and strong sources of gravitational waves in the low-frequency regime. The double-lined double white dwarf (DBL)…

V960~Mon is an FU Orionis object that shows strong evidence of a gravitationally unstable spiral arm that is fragmenting into several dust clumps. We report the discovery of a new substellar companion candidate around this young star,…

We present `James Webb Space Telescope' observations of M4 -- the closest globular cluster -- that probe the lower Main Sequence down to the hydrogen-burning limit. The unveiled stellar sequence reaches much fainter luminosities than…

I measure and collect timings of phase markers (like eclipse times) for the orbits of 25 X-ray binaries (XRBs) so as to calculate the steady evolutionary period change ($\dot{P}$). I combine these with my observed $\dot{P}$ measures from 52…

We present new time-series CCD \emph{VR} photometry of the globular cluster NGC 5634. We aim to use the known RR Lyrae stars, members of the cluster, as indicators of mean metallicity and distance. Accurate coordinates, periods and an…

The Sun continuously expels a fraction of its own mass in the form of a steadily accelerating outflow of ionized gas called the "solar wind." The solar wind is the extension of the Sun's hot (million-degree Kelvin) outer atmosphere that is…

To elucidate the cascade direction of the solar wind turbulence, we analyzed magnetic helicity density spectra from the Parker Solar Probe data across more than 500 heliocentric distances. For the first time, we confirmed a persistent…

We present a spectral atlas of solar spectroheliograms covering the wavelength range from 3641 to 6600 \AA, with continuous coverage between 3711 and 5300 \AA, and sparser coverage beyond this range. The spectral resolution varies between R…

Context: HD 49798 is a bright ($m_{\rm V} = 8.287$), hot (effective temperature $T_{\rm eff} = 45000$ K) subdwarf star of the spectral type O (sdO). It is the only confirmed sdO-type mass-donor star of an X-ray binary that has a high-mass…