Ghostly Stellar Halos in Dwarf Galaxies Hoyoung Kang Department of Physics, University of Maryland Our study aims at probing the typical masses of the smallest and faintest galaxies that have ever formed in the universe. We carry out numerical simulations to characterize the size, stellar mass, and stellar mass surface density of stellar halos as a function of dark matter halo mass and a parame...

The Kepler mission provides a wealth of multiple transiting planet systems (MTPSs). The formation and evolution of multi-planet systems are likely to be influenced by companion stars given the abundance of multiple stellar systems. We study the influence of stellar companions by measuring the stellar multiplicity rate of MTPSs. We select 138 bright (KP < 13.5) Kepler MTPSs and search for stella...

We derive detailed theoretical models for 1074 nearby stars from the SPOCS (Spectroscopic Properties of Cool Stars) Catalog. The California and Carnegie Planet Search has obtained high-quality (R ≃ 70000− 90000, S/N ≃ 3− 500) echelle spectra of over 1000 nearby stars taken with the Hamilton spectrograph at Lick Observatory, the HIRES spectrograph at Keck, and UCLES at the Anglo Australian Obser...

We study the mass-radius relation and second Love number of compact objects made ordinary matter non-self-annihilating fermionic dark for a wide range particle masses, cases weakly strongly interacting matter. obtain stable configurations with radii smaller than 10 km masses similar to Earth- or Jupiter-like stellar objects. In certain parameter ranges, we find numbers which are markedly differ...

Abstract In this paper we examine the stability of stellar configurations in which interior solution is described by a closed Friedmann-Lemaître-Robertson-Walker (FLRW) geometry sourced with charged pressureless fluid and radiation. An interacting vacuum component conformally coupled massive scalar field are also included. Given simple factor for energy transfer between obtain bounded oscillato...

Abstract If the surface tension of dense matter is high enough, a hybrid star composed quark core and hadronic mantle may display sharp interface. Perturbations such lead to conversion reactions occurring in vicinity quark-hadron splitting surface. timescale much larger than perturbation one (slow reactions), changes stellar stability do occur at critical points M(R) curve. As consequence, new ...

Context. Tow important stellar-population parameters (age and metallicity) of the dominant stellar populations (DSPs) of galaxies are usually estimated by comparing the observed absorption line indices or colors to predictions of some simple stellar population models. However, some studies show that there is actually recent star formation in galaxies, including early type ones. This suggests th...