A photoelectric radial-velocity spectrometer on the 1.2-m telescope of the Dominion Astrophysical Observatory

Fletcher, J. M.; Harris, Hugh C.; McClure, R. D.; Scarfe, C. D.

doi:10.1086/131102

Cited by 104 publications

(72 citation statements)

References 5 publications

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“…A fundamental shortcoming of the single-channel methods is a mismatch between the scales of the spectrum and the shifted spectral mask arising at any change in the stellar radial velocity. In the period 1991-1995, Hrivnak et al (2013) used the DAO cross-correlation photometer (Fletcher et al 1982;McClure et al 1985). The above mismatch between the scales was partly compensated for by a special design of the mask (a with a system of tall slits in the range 4000-4600Å, slope changing with distance from the mask center) and a special law of mask motion (at 45 o to the spectrum axis).…”

Section: The Velocity Field In the Atmosphere And Envelopementioning

confidence: 99%

Peculiarities of the atmosphere and envelope of a post-AGB star, the optical counterpart of IRAS 23304+6347

2015

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Based on high-spectral resolution observations performed with the echelle spectrograph NES of the 6-meter telescope, we have studied the peculiarities of the spectrum and the velocity field in the atmosphere and envelope of the optical counterpart of the infrared source IRAS 23304+6347. We have concluded about the absence of significant variations in the radial velocity Vr inferred from atmospheric absorptions and about its coincidence with the systemic velocity deduced from radio data. The envelope expansion velocity Vexp = 15.5 km/s has been determined from the positions of rotational band lines of the C 2 Swan (0; 0) band. A complex emission-absorption profile of the Swan (0; 1) 5635Å has been recorded. Analysis of the multicomponent NaI D doublet line profile has revealed interstellar components V(IS) = −61.6 and −13.2 km/s as well as a circumstellar component with V(CS) =−41.0 km/s whose position corresponds to the velocity inferred from C 2 features. The presence of the interstellar component with Vr =−61.6 km/s in the spectrum allows d = 2.5 kpc to be considered as a lower limit for the distance to the star. A splitting of the profiles for strong absorptions of ionized metals (YII, BaII, LaII, SiII) attributable to the presence of a short-wavelength component originating in the circumstellar envelope has been detected in the optical spectrum of IRAS 23304+6347 for the first time.

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Section: The Velocity Field In the Atmosphere And Envelopementioning

confidence: 99%

Peculiarities of the atmosphere and envelope of a post-AGB star, the optical counterpart of IRAS 23304+6347

2015

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“…The Binary Nature of the Barium Stars McClure et al (1980), andMcClure (1983) have demonstrated that a very large fraction of Ba ii stars (~ 85%) are binary systems. This suggestion was based on radialvelocity observations with a radial-velocity spectrometer (Fletcher et al 1982) of the Griffin (1967) type. It enabled them to measure velocities of a sample of 20 Ba n stars with a precision of better than 0.5 km s -1 over the course of about three years.…”

Section: Nucleosynthesis Related To Barium Starsmentioning

confidence: 99%

“…4-Radial-velocity observations as a function of Julian Date for two extreme Population II CH stars. These data were obtained with the radial-velocity spectrometer described by Fletcher et al (1982). ing CH and R stars for radial-velocity variations (avoiding cooler stars which have light variations).…”

Section: Nucleosynthesis Related To Barium Starsmentioning

confidence: 99%

The barium stars

McClure

1984

PASP

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The barium stars are Population I G-K giants that have enhanced abundances of carbon and s-process elements, and are probably related in their peculiarities to several other carbon enhanced red-giant types such as CH, R, N, and S stars. Since the abundance anomalies in the barium stars are likely the result of mixing of processed material from deep within a stellar interior, and since they are numerous with many bright examples suitable for detailed observations, these stars provide very valuable information on nucleosynthesis, and the advanced stages of stellar evolution. A clue to the origin of the anomalous abundances in the barium stars is the recent discovery that they are likely all members of binary systems.

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“…It has been under observation ever since, and a total of 161 measurements has accumulated. They include 56 obtained with the original spectrometer (Griffin 1967), 33 with the Coravel instrument at OHP (Baranne, Mayor & Poncet 1979), 58 with an analogous instrument at Cambridge, 1 with the ESO Coravel, 10 with the spectrometer (Fletcher et al 1982) of the DAO's 48-inch reflector, and 3 with the spectrometer at the 200-inch Palomar telescope (Griffin & Gunn 1974). They are all listed in Table 2.…”

Section: New Radial Velocities and Orbitmentioning

confidence: 99%

Composite spectra: XVII. 12 Comae, a member of the Coma open cluster

Griffin

Griffin²

2011

Astron Nachr

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The components of binary stars offer the potential to examine the predictions of stellar-evolution theory with particularly tight constraints. Those constraints are further tightened when the binary belongs to a cluster whose properties have been well determined independently. 12 Comae presents both advantages, belonging as it does to the Coma Cluster, Melotte 111. The orbit of 12 Comae has an eccentricity of nearly 0.6 and a period of 13 months. By a process of subtraction we separate the spectra of the component stars, derive a precise double-lined orbit solution, and by modelling the photometry we extract the individual stellar photometric and physical properties, ages and rotation. By fitting theoretical evolutionary tracks to the positions of the stars in the H-R diagram we confirm their individual masses, and derive a ZAMS of ∼0.65 Gyr, which accords well with measurements published for the cluster itself. We show that the primary of 12 Comae is an evolving giant of spectral type ∼G7 and mass 2.6 M , while its secondary (whose spectrum could be isolated particularly cleanly) is an A3 dwarf which has a mass of 2.05 M and has commenced its evolution away from the main sequence. There is evidence that both stars are slightly metal-weak (−0.25 < [Fe/H] < 0.0), well in keeping with analyses of other members of this cluster.

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A photoelectric radial-velocity spectrometer on the 1.2-m telescope of the Dominion Astrophysical Observatory

Cited by 104 publications

References 5 publications

Peculiarities of the atmosphere and envelope of a post-AGB star, the optical counterpart of IRAS 23304+6347

Peculiarities of the atmosphere and envelope of a post-AGB star, the optical counterpart of IRAS 23304+6347

The barium stars

Composite spectra: XVII. 12 Comae, a member of the Coma open cluster

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