Related papers: New Links between Pulsation and Stellar History
The Cepheid mass discrepancy, the difference between mass estimates from stellar pulsation and stellar evolution models, is a long standing challenge for the understanding of stellar astrophysics. We discuss the current state of the mass…
We have made {\it XMM-Newton\/} observations of 14 Galactic Cepheids that have candidate resolved ($\geq$5$\arcsec$) companion stars based on our earlier {\it HST\/} WFC3 imaging survey. Main-sequence stars that are young enough to be…
Pulsations and binarity are both common features of massive stars. The study of pulsating massive stars in eclipsing binary systems hold great potential for constraining stellar structure and evolution theory. However, prior to the all-sky…
Context. The Cepheid mass discrepancy, the difference between masses predicted from stellar evolution and stellar pulsation calculations, is a challenge for the understanding of stellar astrophysics. Recent models of the eclipsing binary…
We recently showed that rotation significantly affects most observable Cepheid quantities, and that rotation, in combination with the evolutionary status of the star, can resolve the long-standing Cepheid mass discrepancy problem. We…
Cepheids have been the cornerstone of the extragalactic distance scale for a century. With high-quality data, these luminous supergiants exhibit a small dispersion in their Leavitt (period-luminosity) relation, particularly at longer…
Context. Many efforts are being made to characterize extrasolar planetary systems and unveil the fundamental mechanisms of planet formation. An important aspect of the problem, which remains largely unknown, is to understand how the planet…
Pulsating variables play a significant role in shaping modern astronomy. Presently it is an exciting era in observational study of variable stars owing to surveys like OGLE and TESS. The vast number of sources being discovered by these…
Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiant - it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses…
The popularity of pulsating stars resides in their capacity of determining several crucial and relevant parameters such as heliocentric distances, ages, metallicity gradients and reddening. RR Lyrae stars are old stellar tracers and have…
The information on stellar parameters and on the stellar interior we can get by studying pulsating stars depends crucially on the available observational constraints: both seismic constraints precision and number of detected modes,…
The extragalactic distance scale is perhaps the most important application of stellar distance indicators. Among these, classical Cepheids are high-accuracy standard candles that support a $1.4\%$ measurement of Hubble's constant, $H_0$.…
Classical Cepheids provide valuable insights into the evolution of stellar multiplicity among intermediate-mass stars. Here, we present a systematic investigation of single-lined spectroscopic binaries (SB1) based on high-precision…
Cepheids are key distance indicators and benchmarks for stellar evolution, yet most of them are members of binary or multiple systems. While spectroscopic surveys and Gaia proper-motion anomalies reveal a high binary fraction, the…
Classical Cepheid variable stars have been important indicators of extragalactic distance and Galactic evolution for over a century. The Spitzer Space Telescope has opened the possibility of extending the study of Cepheids into the mid- and…
The Kepler spacecraft is providing photometric time series with micro-magnitude precision for thousands of variable stars. The continuous time-series of unprecedented time span open up opportunities to study the pulsational variability in…
Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities,…
We present the first results of a Kepler survey of 41 eclipsing binaries that we undertook to search for third star companions. Such tertiaries will periodically alter the eclipse timings through light travel time and dynamical effects. We…
We summarize here the results, most of which are preliminary, of a number of recent observations of the Crab nebula system with the Chandra X-Ray Observatory. We discuss four different topics: (1) The motion on long (> 1yr) time scales of…
Aims: We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, R_C, and I_C…