Search Publications

On the Nature of Stars with Planets

Reid, I. Neill

We consider the metallicities and kinematics of nearby stars known to have planetary-mass companions in the general context of the overall properties of the local Galactic disk. We have used Strömgren photometry to determine abundances both for the extrasolar planet host stars and for a volume-limited sample of 486 F, G, and K stars selected from …

The 7.5 Magnitude Limit Sample of Bright Short-Period Binary Stars. I. How Many Contact Binaries Are There?

Rucinski, Slavek M.

A sample of bright contact binary stars (W UMa type or EW, and related: with β Lyr light curves, EB, and ellipsoidal, ELL-in effect, all but the detached, EA) to the limit of V^max=7.5 mag is deemed to include all discoverable short-period (P<1 day) binaries with photometric variation larger than about 0.05 mag. Of the 32 systems in t…

Autocorrelation Analysis of Hipparcos Photometry of Short-Period Be Stars

Percy, John R.; Hosick, JoAnne; Kincaide, Heather +1 more

We have used Hipparcos epoch photometry and a form of autocorrelation analysis to investigate the amplitude and timescale of the short-period variability of 82 Be stars, including 46 Be stars that were analyzed by Hubert & Floquet using Fourier and CLEAN analysis and 36 other Be stars that were suspected of short-period variability. Our method…

Narrow-Angle Astrometry with the Space Interferometry Mission: The Search for Extrasolar Planets. I. Detection and Characterization of Single Planets

Sozzetti, A.; Lattanzi, M. G.; Casertano, S. +1 more

A decade after the publication of the Hipparcos Catalogue, the Space Interferometry Mission (SIM) will be capable of making selected high-precision astrometric measurements about 3 orders of magnitude more accurate than the Hipparcos survey. We present results from a detailed set of end-to-end numerical simulations of SIM narrow-angle astrometric …

A Precise Orbit Determination of χ¹ Orionis from Astrometric and Radial Velocity Data

Han, Inwoo; Gatewood, George

We have derived an accurate orbit of χ¹ Orionis (HD 39587, HIP 27913, HR 2047) by combining precise astrometric and radial velocity data. The combined orbital analysis yields P=5156.7+/-2.5 days, K₁=1.885+/-0.004 km s^-1, α₁=94.8+/-1.6 mas, e=0.451+/-0.003, and mass ratio (M₂/M₁) q=0…

Solving Olin Wilson's Mystery

Abt, Helmut A.

Wilson showed that G8-M1 dwarfs have a range of 0.30 mag in P-V color whereas the color range for earlier stars is 0.12 mag. He attributed the increased range for the later stars to differing hydrogen-to-metal ratios in the temperature region where most of the electrons come from the metals. I explored those stars using Hipparcos parallaxes and ph…