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The recent detection of a convective core in a main-sequence solar-type star is used here to test particular models of dark matter (DM) particles, those with masses and scattering cross sections in the range of interest for the DM…

Solar and Stellar Astrophysics · Physics 2015-06-15 Jordi Casanellas , Isa M. Brandão , Yveline Lebreton

We investigate the pulsation properties of stellar models representative of $\delta$ Scuti and $\gamma$ Doradus variables. We have calculated a grid of stellar models from 1.2 to 2.2 M$_{\odot}$, including the effects of both rotation and…

Solar and Stellar Astrophysics · Physics 2017-11-08 C. C. Lovekin , J. A. Guzik

We have explored a sample of suspected A-type binaries in a systematic way, both spectroscopically and photometrically. Due to their location in the H-R diagram, indications of pulsation and/or chemical peculiarities among these suspected…

We study the emergence and coherence of stochastic oscillations in star networks of excitable elements in which peripheral nodes receive independent random inputs. A biophysical model of a distal branch of sensory neuron in which peripheral…

Biological Physics · Physics 2016-04-21 Justus A. Kromer , Lutz Schimansky-Geier , Alexander B. Neiman

Gravity waves (or their signatures) are detected in stars thanks to helio- and asteroseismology and they may play an important role in the evolution of stellar angular momentum. Moreover, the observational study of the CoRoT target HD51452…

Solar and Stellar Astrophysics · Physics 2014-05-08 Stéphane Mathis , Coralie Neiner , Nguyet Tran Minh

We find that the convective motion in the envelopes of red supergiant (RSG) stars supplies a non-negligible stochastic angular momentum to the mass that a secondary star accretes in a common envelope evolution (CEE), such that jets that the…

Solar and Stellar Astrophysics · Physics 2023-08-08 Noam Dori , Ealeal Bear , Noam Soker

We examine the effect of dynamical tides raised by a companion on a solar-type star. In these binaries, gravity or g mode oscillations are excited by the companion in the radiative region beneath the convective envelope of the star. They…

Astrophysics · Physics 2007-05-23 C. Terquem , J. C. B. Papaloizou , R. P. Nelson , D. N. C. Lin

We estimate the amount of angular momentum transferred by the low-frequency oscillations detected in the rapidly rotating hot Be star HD 51452. Here, we assume that the oscillations detected are stochastically excited by convective motions…

Solar and Stellar Astrophysics · Physics 2015-06-19 Umin Lee , Coralie Neiner , Stéphane Mathis

We calculate overstable convective modes of uniformly rotating hot Jupiters, which have a convective core and a thin radiative envelope. Convective modes in rotating planets have complex frequency $\omega$ and are stabilized by rapid…

Earth and Planetary Astrophysics · Physics 2019-02-20 Umin Lee

We briefly review progress in developing a pathway to nonlinear astereoseismology, both from theoretical and observational aspects. As predicted by the theory of weak nonlinear interactions between resonant modes, their amplitude and…

Solar and Stellar Astrophysics · Physics 2023-02-07 Weikai Zong , Stéphane Charpinet , Gérard Vauclair , Jian-Ning Fu , Xiao-Yu Ma

We calculate overstable convective (OsC) modes of $2M_\odot$, $4M_\odot$, and $20M_\odot$ main sequence stars. To compute non-adiabatic OsC modes in the core, we assume $(\nabla\cdot\vec{F}_C)^\prime=0$ as a prescription for the…

Solar and Stellar Astrophysics · Physics 2021-06-09 Umin Lee

Context. This research paper contains light curve modelling, spectroscopy and detailed asteroseismic studies for four out of five in total semidetached eclipsing binaries with a delta Scuti component, that have been detected to date through…

Solar and Stellar Astrophysics · Physics 2017-11-22 Alexios Liakos

In the present work, we study correlations between stellar fundamental parameters and the oscillation amplitude for delta Scuti stars. We present this study for a sample of 17 selected delta Scuti stars belonging to 5 young open clusters.…

Astrophysics · Physics 2009-11-07 J. C. Suarez , E. Michel , F. Perez Hernandez , Y. Lebreton , Z. P. Li , L. Fox Machado

RCB stars are $L\approx10^4\,L_{\odot}$ solar-mass objects that can exhibit large periods of extinction from dust ejection episodes. Many exhibit semiregular pulsations in the range of $30-50$ days with semi-amplitudes of $0.05-0.3$…

Solar and Stellar Astrophysics · Physics 2023-11-20 Tin Long Sunny Wong , Lars Bildsten

The excitation of pulsation modes in beta Cephei and Slowly Pulsating B stars is known to be very sensitive to opacity changes in the stellar interior where T~2 10^5 K. In this region differences in opacity up to ~50% can be induced by the…

Astrophysics · Physics 2009-11-13 Andrea Miglio , Josefina Montalban , Marc-Antoine Dupret

We identify delta Scuti pulsators amongst members of the recently-discovered Cep--Her Complex using light curves from the Transiting Exoplanet Survey Satellite (TESS). We use Gaia colours and magnitudes to isolate a subsample of provisional…

Solar and Stellar Astrophysics · Physics 2024-10-10 Simon J. Murphy , Timothy R. Bedding , Anuj Gautam , Ronan P. Kerr , Prasad Mani

Analyses of a 3D simulation of the upper layers of a solar convective envelope provide constraints on the physical quantities which enter the theoretical formulation of a stochastic excitation model of solar p modes, for instance the…

Astrophysics · Physics 2009-11-07 R. Samadi , A. Nordlund , R. F. Stein , M. J. Goupil , I. Roxburgh

In this paper we describe a new class of pulsating stars, the prototype of which is the bright, early, F-type dwarf, Gamma Doradus. These stars typically have between 1 and 5 periods ranging from 0.4 to 3 days with photometric amplitudes up…

Astrophysics · Physics 2009-10-31 A. B. Kaye , G. Handler , K. Krisciunas , E. Poretti , F. M. Zerbi

This work concerns the study of the properties of convective cores in main-sequence models of solar-like pulsators and what information they may hold about stellar ages. We verified that the maximum absolute frequency derivative of…

Solar and Stellar Astrophysics · Physics 2014-01-10 I. M. Brandão , M. S. Cunha , J Christensen-Dalsgaard

We identify stars in the $\delta$ Sct instability strip that do not pulsate in p modes at the 50-$\mu$mag limit, using Kepler data. Spectral classification and abundance analyses from high-resolution spectroscopy allow us to identify…

Solar and Stellar Astrophysics · Physics 2015-06-23 Simon J. Murphy , Timothy R. Bedding , Ewa Niemczura , Donald W. Kurtz , Barry Smalley