Contribution to the study of F‐G‐K‐M binaries: XII. Orbital elements of seven new spectroscopic binaries

Carquillat, J. M.; Prieur, Jean‐Louis

doi:10.1002/asna.200710829

Cited by 6 publications

(5 citation statements)

References 19 publications

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“…An orbital solution was presented by Carquillat & Prieur (2008), who found a period of 1308 days, an eccentricity e = 0.182, and a lower limit on the white dwarf mass of 0.6 M . The similarity of Table 2.…”

Section: Nq Gemmentioning

confidence: 99%

“…The star NQ Gem is listed as a suspected symbiotic star in the catalogue of Belczyński et al (2000) because it shows a ratio of SiIII]/CIII] that is similar to that of other symbiotic stars. An orbital solution was presented by Carquillat & Prieur (2008), who found a period of 1308 days, an eccentricity e=0.182, and a lower limit on the white dwarf mass of 0.6 M ⊙ . The similarity of the optical spectra of NQ Gem and T CrB was noted by Greene & Wing (1971).…”

Section: Nq Gemmentioning

confidence: 99%

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Symbiotic stars in X-rays

Luna

Sokoloski

Mukai

et al. 2013

A&A

119

175

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Until recently, symbiotic binary systems in which a white dwarf accretes from a red giant were thought to be mainly a soft X-ray population. Here we describe the detection with the X-ray Telescope (XRT) on the Swift satellite of nine white dwarf symbiotics that were not previously known to be X-ray sources and one that had previously been detected as a supersoft X-ray source. The nine new X-ray detections were the result of a survey of 41 symbiotic stars, and they increase the number of symbiotic stars known to be X-ray sources by approximately 30%. The Swift/XRT telescope detected all of the new X-ray sources at energies greater than 2 keV. Their X-ray spectra are consistent with thermal emission and fall naturally into three distinct groups. The first group contains those sources with a single, highly absorbed hard component that we identify as probably coming from an accretion-disk boundary layer. The second group is composed of those sources with a single, soft X-ray spectral component that probably originates in a region where low-velocity shocks produce X-ray emission, i.e., a colliding-wind region. The third group consists of those sources with both hard and soft X-ray spectral components. We also find that unlike in the optical, where rapid, stochastic brightness variations from the accretion disk typically are not seen, detectable UV flickering is a common property of symbiotic stars. Supporting our physical interpretation of the two X-ray spectral components, simultaneous Swift UV photometry shows that symbiotic stars with harder X-ray emission tend to have stronger UV flickering, which is usually associated with accretion through a disk. To place these new observations in the context of previous work on X-ray emission from symbiotic stars, we modified and extended the α/β/γ classification scheme for symbiotic-star X-ray spectra that was introduced by Muerset et al. based upon observations with the ROSAT satellite, to include a new δ classification for sources with hard X-ray emission from the innermost accretion region. Because we have identified the elusive accretion component in the emission from a sample of symbiotic stars, our results have implications for the understanding of wind-fed mass transfer in wide binaries, and the accretion rate in one class of candidate progenitors of type Ia supernovae.

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Section: Nq Gemmentioning

confidence: 99%

Section: Nq Gemmentioning

confidence: 99%

Symbiotic stars in X-rays

Luna

Sokoloski

Mukai

et al. 2013

A&A

119

175

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“…We will see that an effective temperature threshold Barnbaum et al (1996); 2: Bartkevicius (1996); 3: Eglitis et al (2003); 4: Keenan (1993); 5: Keenan & Morgan (1941); 6: Lee & Bartlett (1944);7: McClure (1970); 8: Morgan & Keenan (1973);9: Sanford (1944); 10: Schild (1973);11: Schmitt (1971);12: Shane (1928); 13: Stock & Welhau (1956);14: Upgren (1962);15: Vandervort (1958);16: Yamashita (1972);17: Yamashita (1975). The following stars show evidence of binarity: HIP 36 623 (Carquillat & Prieur 2008), HIP 109 158 (Makarov & Kaplan 2005), HIP 53 832 (Platais et al 2003) andHIP 85 750 (McClure 1997). of ∼3600 K seems to be a good criterion to distinguish between early-and late-R stars. This will lead to a spectral classification in agreement with the Knapp et al (2001) criterion above, and with other characteristics that differentiate the two subtypes of R stars.…”

Section: Spectral Classificationmentioning

confidence: 99%

“…The late-R star HIP 36 623 is a symbiotic star detected by time-variations of the ultra-violet continuum due probably to the presence of a white dwarf companion (Johnson et al 1988;Belczyński et al 2000;Munari & Zwitter 2002). Recently, Carquillat & Prieur (2008) estimate that the components of the system have masses of 2.5 M ⊙ and 0.6 M ⊙ . On the other hand, HIP 109 158 appears in the catalogue of Hipparcos astrometric binaries with accelerated proper motions (Makarov & Kaplan 2005).…”

Section: Binaritymentioning

confidence: 99%

The chemical composition of carbon stars. The R-type stars

Zamora¹,

Abia²,

Plez

et al. 2009

A&A

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Aims. The aim of this work is to shed some light on the problem of the formation of carbon stars of R-type from a detailed study of their chemical composition.Methods. We use high-resolution and high signal-to-noise optical spectra of 23 R-type stars (both early-and late-types) selected from the Hipparcos catalogue. The chemical analysis is made using spectral synthesis in LTE and state-of-the-art carbon-rich spherical model atmospheres. We derive their CNO content (including the 12 C/ 13 C ratio), average metallicity, lithium, and light (Sr, Y, Zr) and heavy (Ba, La, Nd, Sm) s-element abundances. The observed properties of the stars (galactic distribution, kinematics, binarity, photometry and luminosity) are also discussed. Results. Our analysis shows that late-R stars are carbon stars with identical chemical and observational characteristics as the normal (N-type) AGB carbon stars. The s-element abundance pattern derived can be reproduced by low-mass AGB nucleosynthesis models where the 13 C(α, n) 16 O reaction is the main neutron donor. We confirm the results of the sole previous abundance analysis of early-R stars, namely that they are carbon stars with near solar metallicity showing enhanced nitrogen, low 12 C/ 13 C ratios and no s-element enhancements. In addition, we have found that early-R stars have Li abundances larger than expected for post RGB tip giants. We also find that a significant number (∼40%) of the early-R stars in our sample are wrongly classified, probably being classical CH stars and normal K giants. Conclusions. On the basis of the chemical analysis, we confirm the previous suggestion that late-R stars are just misclassified N-type carbon stars in the AGB phase of evolution. Their photometric, kinematic, variability and luminosity properties are also compatible with this. In consequence, we suggest that the number of true R stars is considerably lower than previously believed. This alleviates the problem of considering R stars as a frequent stage in the evolution of low-mass stars. We briefly discuss the different scenarios proposed for the formation of early-R stars. The mixing of carbon during an anomalous He-flash is favoured, although no physical mechanism able to trigger that mixing has been found yet. The origin of these stars still remains a mystery.

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“…-Cataclysmic binaries and X-ray binaries [197]: http://physics.open.ac.uk/RKcat/ (update RKcat7.8, 2007) -Chromospherically active binaries [198]: http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V/76 -Symbiotic stars * http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/A+AS/146/407 [69] * See as well the series of papers by Carquillat [199], R.E. Griffin [200],…”

Section: A List Of Resources On Binary Starsmentioning

confidence: 99%

Detection methods of binary stars with low- and intermediate-mass components

Jorissen¹,

Frankowski²

2008

AIP Conference Proceedings

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This paper reviews methods which can be used to detect binaries involving low-and intermediate-mass stars, with special emphasis on evolved systems. Besides the traditional methods involving radial-velocity or photometric monitoring, the paper discusses as well less known methods involving astrometry or maser (non-)detection. An extensive list of internet resources (mostly catalogues/databases of orbits and individual measurements) for the study of binary stars is provided at the end of the paper. FIGURE 2. The various kinds of symbiotic stars (SyS) and of peculiar red giants, in a plane spectraltype vs. metallicity. Within each box, the first line (slanted font) lists the stellar family, the second line (calligraphic font) indicates whether or not stars from that family are enriched in s-process elements (either from internal nucleosynthesis -"Intrinsic Ba" -or from mass transfer across a binary system -"Ba" standing for Extrinsic Ba). The last lines (regular font) provide the binary properties of that family: binary (short or long periods) or non-binary, SyS or non-SyS. Each box has been assigned a number, for easy reference in the text. The horizontal line with an arrow in the middle of the figure is to indicate that the thermally-pulsing AGB phase (where the s-process nucleosynthesis takes place) involves different spectral types at low-and near-solar metallicity. (From [5]) synthesis, being more efficient at low metallicities [19], and (iii) the location of evolutionary tracks in the Hertzsprung-Russell diagram (hence the correspondence between spectral type and evolutionary status, like the onset of thermally-pulsing AGB, where the s-process operates, will depend on metallicity). Fig. 2 therefore considers three different metallicity ranges: (i) [Fe/H]< −1, corresponding to the halo population; (ii) −1 ≤[Fe/H]≤ 0, or disk metallicity; (iii) [Fe/H]≥ 0, solar and super-solar metallicities found in the young thin disk.The horizontal axis in Fig. 2 displays spectral type. At a given metallicity, spectral type is a proxy for evolutionary status: the giant components in L&IM binaries may either be located on the first red giant branch (RGB), in the core He-burning phase (which is hardly distinguishable from the lower RGB/AGB; CH giants probably belong to that phase), He-shell burning early AGB (E-AGB), or on the thermally-pulsing AGB (TP-AGB) phase, where the s-process operates.Symbiotic activity is expected in the middle of this spectral sequence, because (i) at the left end, stars (like CH) are not luminous enough to experience a mass loss sufficient to power symbiotic activity; (ii) at the right end, the stars with the barium syndrome need not be binaries. Indeed, in TP-AGB stars, heavy-elements are synthesized in the stellar interior and dredged-up to the surface, so that "intrinsic Ba" (or S) stars occupy the rightmost boxes -4 and 8 -of Fig. 2, and hence need not exhibit any symbiotic activity since they are single stars (For examples of stars belonging to box 4, see [18] and [20]). Such evolved giants whic...

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Contribution to the study of F‐G‐K‐M binaries: XII. Orbital elements of seven new spectroscopic binaries

Cited by 6 publications

References 19 publications

Symbiotic stars in X-rays

Symbiotic stars in X-rays

The chemical composition of carbon stars. The R-type stars

Detection methods of binary stars with low- and intermediate-mass components

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