Related papers: Long Secondary Periods in Variable Red Giants

We perform a search for faint, common proper motion companions of Hipparcos stars using the recently published LSPM-north catalog of stars with proper motion mu>0.15 arcsec/yr. Our survey uncovers a total of 521 systems with angular…

Context. Fast rotating red giants in the upper part of the red giant branch have surface velocities that cannot be explained by single star evolution. Aims. We check whether tides between a star and a planet followed by planet engulfment…

Oscillation modes with a mixed character, as observed in evolved low-mass stars, are highly sensitive to the physical properties of the innermost regions. Measuring their properties is therefore extremely important to probe the core, but…

In this paper, we collect a sample of 81 ellipsoidal red giant binaries in the Large Magellanic Cloud (LMC), and we study their orbital natures individually and statistically. The sample contains 59 systems with circular orbits and 22…

We present period-luminosity relations for more than 23,000 red giants in the Large Magellanic Cloud observed by the OGLE-II microlensing project. The OGLE period values were combined with the 2MASS single-epoch JHK photometric data. For…

Observations show that luminous blue variables (LBVs) are far more dispersed than massive O-type stars, and Smith & Tombleson suggested that these large separations are inconsistent with a single-star evolution model of LBVs. Instead, they…

We review the recent impact of microlensing projects on our understanding of pulsating red giant stars. Discussed are red giant stars' pulsation properties (period--luminosity relations, period changes, mode switchings), Red Giant Branch…

We present the peculiar in-plane velocities derived from the LAMOST red clump stars. From the variations of the in-plane velocity with the Galactocentric radius for the young and old red clump stars, we are able to identify two types of…

Among 19 red-giant stars belonging to eclipsing binary systems that have been identified in Kepler data, 15 display solar-like oscillations. We study whether the absence of mode detection in the remaining 4 is an observational bias or…

Millisecond pulsars (MSPs) orbiting helium white dwarfs (WDs) in eccentric orbits challenge the established binary evolution paradigm that predicts efficient orbital circularization during the mass transfer episode that spins up the pulsar.…

Given the high incidence of binaries among mature field massive stars, it is clear that multiplicity is an inevitable outcome of high-mass star formation. Understanding how massive multiples form requires the study of the birth environments…

We provide an analysis of the mass ratio distribution as gathered from almost all of the 559 orbital solutions derived by Professor Roger Griffin in his long series in the Observatory Magazine about "Spectroscopic Binary Orbits from…

PSR J1903+0327 is a mili-second pulsar with a mass of 1.67 M_{\odot} in a highly eccentric orbit (e=0.44) around a main-sequence star. This unique system cannot be reconciled with current observations where milli-second pulsars are…

Pulsars are neutron stars that rotate rapidly. Most of the pulsars in binary systems tend to spin faster than those in isolation. According to binary evolution theory, radio pulsars in binary systems can have various types of companion…

We find that $\sim 15-20$ per cent of A-type stars or red giants are bound with a massive companion ($M_{\rm secondary} > 1M_{\odot}$) in an intermediate wide orbit ($0.5<P<5000\mbox{ yr}$). These massive binaries are expected to form…

Stars exhibit a bewildering variety of rapidly variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotation. The principal Rubin Observatory Legacy Survey of Space and…

Low-mass giants with large amounts of lithium (Li) have challenged stellar evolution for decades. One of the possibilities usually discussed to explain them involves the interaction with a close binary companion. This predicts that when…

Using extensive HST imaging, combined with Chandra X-ray and Parkes radio data, we have detected the optical binary companion to a second millisecond pulsar (MSP) in the globular cluster 47 Tucanae. This faint (V=22.3) blue (V-I=0.7) star…

Motivated by the existence of binary systems where a stellar-mass black hole is bound to a normal star, we selected four red giants with large radial velocity (RV) variation from the survey of SIM grid stars and monitored their RVs for…

We compile observations of early-type binaries identified via spectroscopy, eclipses, long-baseline interferometry, adaptive optics, common proper motion, etc. Each observational technique is sensitive to companions across a narrow…