Related papers: Long Secondary Periods in Variable Red Giants

Existing upper limits on variations in the photospheric radius of the Sun during the solar magnetic activity cycle are at a fractional amplitude of 2x10^{-4}. At that level, the transit duration of a close-in planet around a Sun-like star…

We have used many decades of visual observations from the AAVSO International Database, and the AAVSO time-series analysis package VSTAR, to study the long-term changes in period, amplitude, and mean magnitude in about 30 normal pulsating…

We present two epochs of radial velocities of the first imaged T dwarf Gliese 229B obtained with Keck/NIRSPEC. The two radial velocities are discrepant with one another, and with the radial velocity of the host star, at $\approx$$11\sigma$…

Up to now, most planet search projects have concentrated on F to K stars. In order to considerably widen the view, we have stated a survey for planets of old, nearby brown dwarfs and very low mass stars. Using UVES, we have observed 26…

Using the Hamilton Echelle Spectrograph at Lick Observatory, we have obtained precise radial velocities (RVs) of a sample of 373 G- and K-giant stars over more than 12 years, leading to the discovery of several single and multiple planetary…

Barium (Ba), CH, and extrinsic or Tc-poor S-type stars are evolved low- and intermediate-mass stars that show enhancement of slow-neutron-capture-process elements on their surface, an indication of mass accretion from a former asymptotic…

Typical radio pulsars are magnetized neutron stars that are born rapidly rotating and slow down as they age on time scales of 10 to 100 million years. However, millisecond radio pulsars spin very rapidly even though many are billions of…

We discuss mm/submm spectra of a sample of symbiotic binary systems, and compare them with popular models proposed to account for their radio emission. We find that radio emission from quiescent S-type systems originates from a conical…

This project began as a search for triple-mode pulsating red giants (PRGs) among known double-mode PRGs,, using AAVSO visual data. It then expanded to include a check on the reality and significance of some double-mode PRGs. We identified…

We have completed a Monte-Carlo simulation to estimate the effect of binary star orbits on the measured velocity dispersion in dwarf spheroidal galaxies. This paper analyses previous attempts at this calculation, and explains the…

Period-luminosity (PL) sequences of long period variables (LPVs) are commonly interpreted as different pulsation modes, but there is disagreement on the modal assignment. Here, we re-examine the observed PL sequences in the Large Magellanic…

We present timing and orbital phase-resolved polarimetry of the millisecond pulsar (MSP) J2101$-$4802, having a spin period of 9.48~ms and dispersion measure (DM) $25.05\ \mathrm{pc\ cm^{-3}}$ discovered with the Giant Meter Radio Telescope…

Turbulent motions in the convective envelope of red giants excite a rich spectrum of solar-like oscillation modes. Observations by CoRoT and Kepler have shown that the mode amplitudes increase dramatically as the stars ascend the red giant…

RV surveys of evolved stars allow us to probe a higher stellar mass range compared to main-sequence samples. Differences between the planet populations can be caused by either the differing stellar mass or stellar evolution. To properly…

We investigate the pulsational properties of RSG models --- which we evolve from ZAMS masses in the range 10 to $20 \Msun$ --- by means of linear and non-linear calculations. We find period and growth rate of the dominant fundamental mode…

Random changes in pulsation period are well established in cool pulsating stars, in particular the red giant variables: Miras, semi-regulars of types A and B, and RV Tau variables. Such effects are also observed in a handful of Cepheids,…

Binary millisecond pulsars (MSPs) are detached binary systems consisting of a MSP and a He white dwarf. If the initial orbital periods of binary MSPs are less than 0.3 day, they would evolve toward ultra-compact binary pulsars due to the…

Low mass white dwarfs are the remnants of disrupted red giant stars in binary millisecond pulsars and other exotic binary star systems. Some low mass white dwarfs cool rapidly, while others stay bright for millions of years due to stable…

We examine high-cadence space photometry taken by the Transiting Exoplanet Survey Satellite (TESS) of a sample of evolved massive stars (26 Wolf-Rayet stars and 8 Luminous Blue Variables or candidate LBVs). To avoid confusion problems, only…

We present a systematic study of the evolution of intermediate- and low-mass X-ray binaries consisting of an accreting neutron star of mass $1.0-1.8 M_{\odot}$ and a donor star of mass $1.0-6.0 M_{\odot}$. In our calculations we take into…