Related papers: iSTARMOD: A Python Code to Quantify Chromospheric …
Asteroseismic methods offer a means to investigate stellar activity and activity cycles as well as to identify those properties of stars which are crucial for the operation of stellar dynamos. With data from CoRoT and \textit{Kepler},…
We present SPIDERMAN, a fast code for calculating exoplanet phase curves and secondary eclipses with arbitrary surface brightness distributions in two dimensions. Using a geometrical algorithm, the code solves exactly the area of sections…
Intensity interferometry (II) exploits the second-order correlation to acquire the spatial frequency information of an object, which has been used to observe distant stars since 1950s. However, due to unreliability of employed imaging…
Accurate atomic models for astrophysical plasma can be very complex, requiring thousands of states. However, for a variety of applications such as large-scale forward models of the Stokes parameters of a spectral line in the solar corona,…
Low-energy cosmic-rays (CRs) control the thermo-chemical state and the coupling between gas and magnetic fields in dense molecular clouds, the sites of star-formation. However, current estimates of the low-energy CR spectrum ($E \lesssim 1$…
Starspots, plages, and activity cycles cause radial velocity variations that can either mimic planets or hide their existence. To verify the authenticity of newly discovered planets, observers may search for periodicity in spectroscopic…
We report on two distinct computational approaches to self-consistently measure photospheric properties of large samples of stars. Both procedures consist of a set of several semi-integrated tasks based on shell and Python scripts, which…
Based on the conventional Mach-Zehnder interferometer, we propose a metrological scheme to improve phase sensitivity. In this scheme, we use a coherent state and a squeezed vacuum state as input states, employ multi-photon-subtraction…
We present new 14 high-resolution echelle spectra to discuss the level of chromospheric activity of DM UMa in {He I} D3, {Na I} D1, D2, Halpha, and {Ca II} infrared triplet lines (IRT). It is the first time to discover the emissions above…
Analysing extended emission in photometric observations of star-forming regions requires maps free from compact foreground, embedded, and background sources, which can interfere with various techniques used to characterise the interstellar…
A new, improved version of a cosmic crystallography method for constraining cosmic topology is introduced. Like the circles-in-the-sky method using CMB data, we work in a thin, shell-like region containing plenty of objects. Two pairs of…
Hyperspectral anomaly detection (HAD), a crucial approach for many civilian and military applications, seeks to identify pixels with spectral signatures that are anomalous relative to a preponderance of background signatures. Significant…
Based on the near-IR spectra of 33 late-type stars in the wide metallicity range (mainly dwarfs and partly giants) obtained with IRCS+AO188 of the Subaru Telescope, we confirmed that He I 10830A line is seen in absorption in almost all…
From stellar spectra, a variety of physical properties of stars can be derived. In particular, the chemical composition of stellar atmospheres can be inferred from absorption line analyses. These provide key information on large scales,…
Aims: Accretion rates in low-mass protostars can be highly variable in time. Each accretion burst is accompanied by a temporary increase in luminosity, heating up the circumstellar envelope and altering the chemical composition of the gas…
Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase…
We investigate the potential of multi-colour photometry for partial mode identification in both long- and short-period variable subdwarf B stars. The technique presented is based on the fact that the frequency dependence of an oscillation's…
Kjeldsen et al. (1995, AJ 109, 1313; astro-ph/9411016) have developed a new technique for measuring stellar oscillations and claimed a detection in the G subgiant eta Boo. The technique involves monitoring temperature fluctuations in a star…
Employing a new machine learning method, named hierarchical extreme learning machine (HELM) algorithm, we identified 56 hot subdwarf stars in the first data release (DR1) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope…
Transmission spectroscopy can be used to constrain the properties of exoplanetary atmospheres. During a transit, the light blocked from the atmosphere of the planet leaves an imprint in the light coming from the star. This has been shown…