Binary Properties from Cepheid Radial Velocities (CRaV)

Abstract

We have examined high accuracy radial velocities of Cepheids to determine the binary frequency. The data are largely from the CORAVEL spectrophotometer and the Moscow version, with a typical uncertainty of $\le 1$~km~s${}^{-1}$, and a time span from 1 to 20 years. A systemic velocity was obtained by removing the pulsation component using a high order Fourier series. From this data we have developed a list of stars showing no orbital velocity larger than $\pm 1$~km~s${}^{-1}$. The binary fraction was analyzed as a function of magnitude, and yields an apparent decrease in this fraction for fainter stars. We interpret this as incompleteness at fainter magnitudes, and derive the preferred binary fraction of $29\pm 8$\% ( $20\pm 6$\% per decade of orbital period) from the brightest 40 stars. Comparison of this fraction in this period range (1-20 years) implies a large fraction for the full period range. This is reasonable in that the high accuracy velocities are sensitive to the longer periods and smaller orbital velocity amplitudes in the period range sampled here. Thus the Cepheid velocity sample provides a sensitive detection in the period range between short period spectroscopic binaries and resolved companions. The recent identification of $\delta$ Cep as a binary with very low amplitude and high eccentricity underscores the fact that the binary fractions we derive are lower limits, to which other low amplitude systems will probably be added. The mass ratio (q) distribution derived from ultraviolet observations of the secondary is consistent with a flat distribution for the applicable period range (1 to 20 years).

accepted for publication in AJ

References in corpus (35)

• Binary interaction dominates the evolution of massive stars
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• Stellar Multiplicity
• The High Angular Resolution Multiplicity of Massive Stars
• The VLT-FLAMES Tarantula Survey VIII. Multiplicity properties of the O-type star population
• Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations
• A spectroscopic survey on the multiplicity of high-mass stars
• The VAST Survey - III. The multiplicity of A-type stars within 75 pc
• From binaries to multiples II: hierarchical multiplicity of F and G dwarfs
• Toward Complete Statistics of Massive Binary Stars: Penultimate Results from the Cygnus OB2 Radial Velocity Survey
• Direct Detection of the Close Companion of Polaris with the Hubble Space Telescope
• Revealing δ Cephei's Secret Companion and Intriguing Past
• Fragmentation of Massive Protostellar Disks
• Calibrating the Cepheid Period-Luminosity relation from the infrared surface brightness technique I. The p-factor, the Milky Way relations, and a universal K-band relation
• The mass ratio distribution of B-type visual binaries in the Sco OB2 association
• The effect of metallicity on the Cepheid Period-Luminosity relation from a Baade-Wesselink analysis of Cepheids in the Galaxy and in the Small Magellanic Cloud
• The MACHO Project Large Magellanic Cloud variable star inventory. XI. Frequency analysis of the fundamental mode RR Lyrae stars
• The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor
• Observational studies of Cepheid amplitudes. I - Period-amplitude relationships for Galactic Cepheids and interrelation of amplitudes
• Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity
• On the evolutionary and pulsation mass of Classical Cepheids: III. the case of the eclipsing binary Cepheid CEP0227 in the Large Magellanic Cloud
• Fundamental parameters of Cepheids. V. Additional photometry and radial velocity for southern Cepheids
• Binary Cepheids: Separations and Mass Ratios in $5M_{\odot }$ Binaries
• Tuning in on Cepheids: Radial velocity amplitude modulations. A source of systematic uncertainty for Baade-Wesselink distances
• Observations of Cepheids with the MOST satellite: Contrast between Pulsation Modes
• The Search for Low-mass Companions of B Stars in the Carina Nebula Cluster Trumpler 16
• Classical Cepheids Require Enhanced Mass Loss
• A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors
• A photometric and spectroscopic study of the brightest northern Cepheids. III. A high-resolution view of Cepheid atmospheres
• Massive Star Multiplicity: The Cepheid W Sgr
• Magnetized neutron star atmospheres: beyond cold plasma approximation
• The occurrence of classical Cepheids in binary systems
• Long-Period Variability in o Ceti
• Discovery of the spectroscopic binary nature of the classical Cepheids FN Aql and V1344 Aql
• Discovery of the spectroscopic binary nature of the Cepheids X Puppis and XX Sagittarii

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