The Orbit and Parallax of Procyon.

Abstract. Complementing the Proper Motions of Fundamental Stars catalogue by Gontcharov et al. (CDS,) the photocentric orbits of some FK5/Hipparcos stars are calculated in a direct combination of the Hipparcos data with astrometric ground-based observational catalogues having epochs later than 1939. Some capabilities and limitations of this method are discussed in a comparison of our results with known orbits of Sirius, Procyon, Rasalhague, µ Cas and others. We conclude that this direct combination is an acceptable tool to discover and investigate photocentric orbits with periods from 10 to 55 years and the semi-major axis of apparent ellipses >0.08 arcsec. It is particularly suitable for pairs with large magnitude difference as well as for calculation of the preliminary orbits of new astrometric binaries which will be considered in forthcoming papers. In this paper new photocentric orbits and component masses are calculated for 4 pairs: α UMa, β LMi, δ And and ξ Aqr.

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“…Photocentric orbits by Strand (1951), Irwin et al (1992) and Girard et al (2000) are shown in Fig. 2 as dashed, • 3 104.…”

Section: α CMI (Procyon)mentioning

confidence: 99%

Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos

Gontcharov

Kiyaeva

2002

A&A

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“…The binary nature of the system is a great opportunity to determine the mass of both companions. The first attempt was made by Strand (1951), who determined the masses of Procyon A and B by determining the parallax and orbital elements of the system. He found that 1.76 ± 0.1 and 0.65 ± 0.05 M , respectively.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional interferometric, spectrometric, and planetary views of Procyon

Chiavassa

Bigot

Kervella

et al. 2012

A&A

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Context. Procyon is one of the brightest stars in the sky and one of our nearest neighbours. It is therefore an ideal benchmark object for stellar astrophysics studies using interferometric, spectroscopic, and asteroseismic techniques. Aims. We use a new realistic three-dimensional (3D) radiative-hydrodynamical (RHD) model atmosphere of Procyon generated with the Stagger Code and synthetic spectra computed with the radiative transfer code Optim3D to re-analyze interferometric and spectroscopic data from the optical to the infrared. We provide synthetic interferometric observables that can be validated using observations. Methods. We computed intensity maps from a RHD simulation in two optical filters centered on 500 and 800 nm (Mark III) and one infrared filter centered on 2.2 μm (Vinci). We constructed stellar disk images accounting for the center-to-limb variations and used them to derive visibility amplitudes and closure phases. We also computed the spatially and temporally averaged synthetic spectrum from the ultraviolet to the infrared. We compare these observables to Procyon data. Results. We study the impact of the granulation pattern on center-to-limb intensity profiles and provide limb-darkening coefficients in the optical as well as in the infrared. We show how the convection-related surface structures affect the visibility curves and closure phases with clear deviations from circular symmetry, from the 3rd lobe on. These deviations are detectable with current interferometers using closure phases. We derive new angular diameters at different wavelengths with two independent methods based on 3D simulations. We find that θ Vinci = 5.390 ± 0.03 mas, which we confirm by comparison with an independent asteroseismic estimation (θ seismic = 5.360 ± 0.07 mas. The resulting T eff is 6591 K (or 6556 K depending on the bolometric flux used), which is consistent with the value of T eff,IR = 6621 K found with the infrared flux method. We measure a surface gravity log g = 4.01 ± 0.03 [cm/s 2 ] that is higher by 0.05 dex than literature values. Spectrophotometric comparisons with observations provide very good agreement with the spectral energy distribution and photometric colors, allowing us to conclude that the thermal gradient in the simulation matches Procyon fairly well. Finally, we show that the granulation pattern of a planet-hosting Procyon-like star has a non-negligible impact on the detection of hot Jupiters in the infrared using interferometry closure phases. It is then crucial to have a comprehensive knowledge of the host star to directly detect and characterize hot Jupiters. In this respect, RHD simulations are very important to achieving this aim.

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“…"22; 2000) is a nearby binary system with an F5 IV-V (Garrison 1990) primary and a white-dwarf secondary. Analysis of spectroscopic, astrometric, and visual observations of this system have yielded (Strand 1951) the orbit, component masses, and parallax of the system. Procyon B (throughout this paper A refers to the primary and B the secondary) is a rare example of a white dwarf whose mass can be directly determined by orbital analysis.…”

Section: Introduction Procyon (=A Canis Minoris=hr 2943 With a =mentioning

confidence: 99%

“…The definitive orbit of Procyon (Strand 1951) is based primarily on astrometric measures of a series of photographic plates taken at the Yerkes and McCormick Observatories from 1915 to 1950. The mass ratio was determined from 17 visual observations of the separation between the primary and its white-dwarf companion taken from 1897 through 1913.…”

Section: Introduction Procyon (=A Canis Minoris=hr 2943 With a =mentioning

confidence: 99%

The orbit and mass of Procyon

Irwin¹,

Fletcher²,

Yang³

et al. 1992

PASP

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ABSTRACT. We have determined the orbit and parallax of the Procyon system (F5 IV-V primary and white-dwarf secondary) using conventional absolute radial velocities, precise relative radial velocities determined with the hydrogen fluoride (HF) absorption-cell technique, and astrometric and visual observations. Our least-squares analysis confirms and strengthens Strand's previous analysis based on more limited material. We derive an absolute parallax of 7r abs =0.2899 ± 0.0074 arcsec. Our parallax result is in excellent agreement with other parallax investigations based on independent material. If we adopt the latest USNO parallax of ^a bs =0.2864 ±0.0023 arcsec, then from our orbital parameters we derive M A = 1.751 ±0.051 M 0 , and M B =0.622 ±0.017 M 0 . For the derived mass of Procyon A (which is consistent with previous results), it has long been known that the luminosity predicted by stellarinterior theory is approximately a factor of 2 larger than the luminosity derived from observations. The errors in this observed luminosity and the above formal standard errors (i.e., our best estimates of the statistical random errors) in our derived mass are too small to explain this discrepancy. If the observed separation of the binary components has been systematically overestimated by approximately 0.2 arcsec, then the derived mass would be reduced, thus resolving the discrepancy. However, the excellent consistency of the separations measured by Aitken and Barnard for a number of years at different sites argues against this interpretation. The stellar-interior theory of Procyon A may need substantial revision.

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The Orbit and Parallax of Procyon.

Cited by 17 publications

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Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos

Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos

Three-dimensional interferometric, spectrometric, and planetary views of Procyon

The orbit and mass of Procyon

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