Related papers: Irradiated stars with convective envelopes
We present evolutionary models for cool brown dwarfs and extra-solar giant planets. The models reproduce the main trends of observed methane dwarfs in near-IR color-magnitude diagrams. We also present evolutionary models for irradiated…
The origin of hot subdwarf B stars (sdBs) is still unclear. About half of the known sdBs are in close binary systems for which common envelope ejection is the most likely formation channel. Little is known about this dynamic phase of binary…
Periodic increases in luminosity arising from variable accretion rates have been predicted for some close pre-main sequence binary stars as they grow from circumbinary disks. The phenomenon is known as "pulsed accretion" and can affect the…
Measuring fundamental stellar parameters is key to fully comprehending the evolution of stars. However, current theoretical models over-predict effective temperatures, and under-predict radii, compared to observations of K and M dwarfs…
Low-mass M dwarfs represent the most common outcome of star formation, but their complex emergent spectra hinder detailed studies of their composition and initial formation. The measurement of isotopic ratios is a key tool that has been…
The radial profiles of gas, stars, and far ultraviolet radiation in 20 dwarf Irregular galaxies are converted to stability parameters and scale heights for a test of the importance of two-dimensional (2D) instabilities in promoting star…
In this paper we present the discovery of a highly unequal-mass eclipsing M-dwarf binary, providing a unique constraint on binary star formation theory and on evolutionary models for low-mass binary stars. The binary is discovered using…
In recent years, analyses of eclipsing binary systems have unveiled differences between the observed fundamental properties of low-mass stars and those predicted by stellar structure models. Particularly, radius and effective temperatures…
Observations made using TESS revealed a sample of low mass stars which show a periodic modulation on a period $<0.2$~d. Surprisingly many of these Ultra Fast Rotating (UFR) stars showed no evidence of flare activity which would be expected…
Tidal heating is often used to interpret "radius anomaly" of hot Jupiters (i.e. radii of a large fraction of hot Jupiters are in excess of 1.2 Jupiter radius which cannot be interpreted by the standard theory of planetary evolution). In…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
We study a warping instability of a geometrically thin, non-self-gravitating, circumbinary disk around young binary stars on an eccentric orbit. Such a disk is subject to both the tidal torques due to a time-dependent binary potential and…
The precise measurement of the masses and radii of stars in eclipsing binary systems provides a window into uncertain processes in stellar evolution, especially mixing at convective boundaries. Recently, these data have been used to…
Stars stripped of their envelope through interaction in a binary are generally not considered when accounting for ionizing radiation from stellar populations, despite the expectation that stripped stars emit hard ionizing radiation, form…
In radiative layers of rotating stars the luminosity carried by circulation currents through a surface of constant entropy (circulation luminosity) is shown to be positive. The corresponding decrease in the temperature gradient is important…
Active, low-mass stars are widely observed to have radii that are larger than predicted by standard stellar models. Proposed mechanisms for this radius inflation generally involve stellar magnetism, either in the form of added pressure…
Radio observations of neutron star binary pulsar systems have constrained strongly the masses of eight neutron stars. Assuming neutron star masses are uniformly distributed between lower and upper bounds $m_l$ and $m_u$, the observations…
While stellar expansion after core-hydrogen exhaustion related to thermal imbalance has been documented for decades, the physical phenomenon of stellar inflation that occurs close to the Eddington limit has only come to the fore in recent…
Accretion of interstellar material by an isolated neutron star is discussed. The point I address here is the interaction between the accretion flow and the stellar magnetosphere. I show that the interchange instabilities of the…
We discuss the internal structure of stars in the mass range 1.5 to 4 M_sun from the PMS to the subgiant phase with a particular emphasis on the convective core and the convective superficial layers. Different physical aspects are…