Search Publications
A 2.4% Determination of the Local Value of the Hubble Constant
Casertano, Stefano; Filippenko, Alexei V.; Foley, Ryan J. +12 more
We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample o…
Determining Ages of APOGEE Giants with Known Distances
Bovy, Jo; Majewski, Steven R.; Feuillet, Diane K. +4 more
We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R ∼ 22,500), near infrared …
Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin I and P/sin I for a Large Sample of Late-K and M Dwarfs
Mullan, D. J.; Gebran, M.; Houdebine, E. R. +1 more
The reliable determination of rotation-activity correlations (RACs) depends on precise measurements of the following stellar parameters: T eff, parallax, radius, metallicity, and rotational speed v sin I. In this paper, our goal is to focus on the determination of these parameters for a sample of K and M dwarfs. In a future paper (Paper…
Pulsation-triggered Mass Loss from AGB Stars: The 60 Day Critical Period
Zijlstra, A. A.; McDonald, I.
Low- and intermediate-mass stars eject much of their mass during the late, red giant branch (RGB) phase of evolution. The physics of their strong stellar winds is still poorly understood. In the standard model, stellar pulsations extend the atmosphere, allowing a wind to be driven through radiation pressure on condensing dust particles. Here, we i…
Evidence for Reflected Light from the Most Eccentric Exoplanet Known
Butler, R. Paul; Mahadevan, Suvrath; Henry, Gregory W. +16 more
Planets in highly eccentric orbits form a class of objects not seen within our solar system. The most extreme case known among these objects is the planet orbiting HD 20782, with an orbital period of 597 days and an eccentricity of 0.96. Here we present new data and analysis for this system as part of the Transit Ephemeris Refinement and Monitorin…
SEEDS Direct Imaging of the RV-detected Companion to V450 Andromedae, and Characterization of the System
Kuzuhara, M.; Tamura, M.; Ishii, M. +49 more
We report the direct imaging detection of a low-mass companion to a young, moderately active star V450 And, that was previously identified with the radial velocity (RV) method. The companion was found in high-contrast images obtained with the Subaru Telescope equipped with the HiCIAO camera and AO188 adaptive optics system. From the public ELODIE …
Tomographic Separation of Composite Spectra. XII. The Physical Properties and Spectral Phase Variability of the Massive Close Binary HD 159176
Penny, Laura R.; Epps, Jacob G.; Snyder, Joseph D.
We present our analysis of the double-lined, O-binary HD 159176 based on observations made with the International Ultraviolet Explorer (IUE). We use cross-correlation methods to obtain radial velocities, confirm the orbital elements, and estimate the UV flux ratio. In addition, we cross-correlate specific regions of the IUE spectra corresponding t…