Related papers: Dynamical masses for the Pleiades binary system HI…
Pulsating stars in binary systems are ideal laboratories to test stellar evolution and pulsation theory, since a direct, model-independent determination of component masses is possible. The high-precision CoRoT photometry allows a detailed…
The precision of stellar models is higher than the precision at which we are able to measure the masses of most stars, with the notable exception of binaries where we can determine dynamical masses of the component stars. In addition to…
Reliable determination of the basic physical properties of hot emission-line binaries with Roche-lobe filling secondaries is important for developing the theory of mass exchange in binaries. It is not easy, however, due to the presence of…
EK Dra (HD 129333) is a young, active, nearby star that is orbited by a low mass companion. By combining new speckle observations with old and new radial velocity measurements we find that the orbit is highly eccentric with e=0.82\pm0.03,…
In this work, we report the discovery and characterization of PSR J1411+2551, a new binary pulsar discovered in the Arecibo 327 MHz Drift Pulsar Survey. Our timing observations of the radio pulsar in the system span a period of about 2.5…
We present results from a radial velocity study of two runaway O-type stars, HD 14633 (ON8.5 V) and HD 15137 (O9.5 III(n)). We find that HD 14633 is a single-lined spectroscopic binary with an orbital period of 15.4083 days. The second…
Direct-imaging exoplanet surveys have discovered a class of 5-20 \Mjup\space substellar companions at separations >100 AU from their host stars, which present a challenge to planet and star formation models. Detailed analysis of the orbital…
We present the discovery in Kepler's $K2$ mission observations and our follow-up radial velocity observations from Keck/HIRES for four eclipsing binary (EB) star systems in the young benchmark Pleiades cluster. Based on our modeling…
We present the results of a spectroscopic and photometric analysis of HD314884, a slowly pulsating B star (SPB) in a binary system with detected soft X-ray emission. We spectrally classify the B star as a B5V-B6V star with T$_{eff}$ =…
Certain lines in spectra of the Galactic microquasar SS 433, in particular the brilliant H alpha line, have been interpreted as emission from a circumbinary disk. In this interpretation the orbital speed of the glowing material is in excess…
We present two Very Large Array observations of the pre-main-sequence star PV Cephei, taken with a separation of 10.5 years. These data show that the proper motions of this star are $\mu_\alpha \cos \delta = +10.9 \pm 3.0$ mas yr$^{-1}$;…
We present recent measurements of the orbital motion in the binaries, DF Tau and ZZ Tau, and in the triples, Elias 12, T Tau, and V853 Oph. We observed these systems with the Fine Guidance Sensors on the Hubble Space Telescope and with…
In this work we present the results of our analysis of medium-resolution LAMOST spectra of late-type candidate members of the Pleiades. We have used the code ROTFIT to determine the atmospheric parameters (Teff, logg, and [Fe/H]), radial…
We present spatially-resolved spectroscopic observations of 10 isolated Galactic HII regions using data from the LAMOST Medium-Resolution Spectroscopic Survey of Nebulae (LAMOST MRS-N). The high spatial resolution of the data allows us to…
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 present new results of a spectroscopic survey of circumstellar HI in the direction of evolved stars made with the Nancay Radiotelescope. The HI line at 21 cm has been detected in the circumstellar shells of a variety of evolved stars:…
Radial velocities from the 2.1 m telescope at McDonald Observatory supplemented with radial velocities from the coude' feed telescope at KPNO provide new precise orbits for the double-lined spectroscopic binaries RR Lyn (A3/A8/A6), 12 Boo…
The binary star delta Sco (HD143275) underwent remarkable brightening in the visible in 2000, and continues to be irregularly variable. The system was observed with the Sydney University Stellar Interferometer (SUSI) in 1999, 2000, 2001,…
We present high resolution spectroscopic observations of the massive X-ray binary system LS I+65 010=2S 0114+650 in the optical wavelength region. A correlation between equivalent width and radial velocity of photospheric absorption lines…
Photographic spectra of Plaskett's Star (PS; HR2420, HD47129, V640 Mon) that were recorded at the Dominion Astrophysical Observatory (DAO) have been digitized with a flatbed scanner. Many of the spectra were recorded during campaigns in…