Related papers: Bisectors of the HARPS Cross-Correlation-Function.…
Surveys of exoplanet host stars are valuable tools for assessing population level trends in exoplanets, and their outputs can include stellar ages, activity, and rotation periods. We extracted chromospheric activity measurements from the…
Gliese 667C is an M1.5V star with a multi-planet system, including planet candidates in the habitable zone (HZ). The exact number of planets in the system is unclear, because the existing radial velocity (RV) measurements are known to…
Context. In order to understand galaxy evolution, it is essential to measure star formation rates (SFRs) across Cosmic times. Aims. The use of radio continuum emission as an extinction-free star formation tracer necessitates a good…
We present a comparative spectral analysis to explore the ability of a cooler Sun model to accurately capture the spectral line shape changes caused by Sunspots. In the search for small Earth-like planets, the effects of stellar surface…
We introduce the notion of a Bayesian analysis motivated `reliability' that gives a truer distinction of cusp-core and other halo-parameters (like mass-concentration) in an ensemble of observed galaxies. Our approach goes beyond the…
Cross-correlations between biased tracers and the dark matter field encode information about the physical variables which characterize these tracers. However, if the physical variables of interest are correlated with one another, then…
The extreme contrast ratios between stars and their planets at optical wavelengths make it challenging to isolate the light reflected by exoplanet atmospheres. Yet, these reflective properties reveal key processes occurring in the…
Dwarf galaxies, due to their shallow gravitational potentials, provide critical environments for studying feedback mechanisms from star formation and its impacts on dwarf galaxy evolution. In particular, radio continuum (RC) observations…
Stellar spectra with a high resolution of 115000 obtained with the HARPS spectrograph provide an opportunity to examine turbulence velocities and their depth distributions in the photosphere of stars. Fourier analysis was performed for 17…
Context: Studies based on high-precision abundance determinations revealed that chemical patterns of solar twins are characterised by the correlation between the differential abundances relative to the Sun and the condensation temperatures…
Classical T Tauri Stars (CTTSs) are highly variable stars that possess gas- and dust-rich disks from which planets form. Much of their variability is driven by mass accretion from the surrounding disk, a process that is still not entirely…
Understanding the physics of star formation is one of the key problems facing modern astrophysics. The Cosmic Infrared Background (CIB), sourced by the emission from all dusty star-forming galaxies since the epoch of reionisation, is a…
Due to stellar rotation, the observed radial velocity of a star varies during the transit of a planet across its surface, a phenomenon known as the Rossiter-McLaughlin (RM) effect. The amplitude of the RM effect is related to the radius of…
The physical interpretation of spectro-interferometric data is strongly model-dependent. On one hand, models involving elaborate radiative transfer solvers are too time consuming in general to perform an automatic fitting procedure and…
Using a full analytical computation of the bispectrum based on the halo model together with the halo occupation number, we derive the bispectrum of the cos- mic infrared background (CIB) anisotropies that trace the clustering of dusty-star-…
We conducted high dispersion spectroscopic observations of 50 superflare stars with Subaru/HDS, and measured the stellar parameters of them. These 50 targets were selected from the solar-type (G-type main sequence) superflare stars that we…
Convective line asymmetries in the optical spectrum of two metal-poor stars, Gmb1830 and HD140283, are compared to those observed for solar metallicity stars. The line bisectors of the most metal-poor star, the subgiant HD140283, show a…
We summarize some of the compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-milliarcsec (sub-mas) angular resolution, UV-Optical spectral imaging observations, which can reveal the…
Electron capture (EC) isotopes are known to provide constraints on the low energy behavior of cosmic rays (CRs), such as re-acceleration. Here we study the EC isotopes within the framework of the dynamic spiral-arms CR propagation model in…
(Abridged) Understanding stellar activity in M dwarfs is crucial for the physics of stellar atmospheres as well as for ongoing radial velocity exoplanet programmes. Despite the increasing interest in M dwarfs, our knowledge of the…