The Solar Chemical Composition

Grevesse, N.; Asplund, Martin; Sauval, A. J.

doi:10.1007/s11214-007-9173-7

Cited by 731 publications

(881 citation statements)

References 31 publications

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“…Keeping the values of log g that we determined in the first stage of the phoebe analysis, rotational velocities calculated under the assumption of tidal locking (which were consistent with preliminar spectral analysis results), and solar abundances pattern fixed (Grevesse et al 2007), we fitted for T eff and [M/H]. As starting values, we used the temperatures we adopted from phoebe analysis (brighter component effective temperature based on the colour-temperature calibration from Worthey & Lee 2011) and solar metallicity.…”

Section: Spectral Analysissupporting

confidence: 62%

Orbital and physical parameters of eclipsing binaries from the ASAS catalogue – IX. Spotted pairs with red giants

Ratajczak

Hełminiak

Konacki

et al. 2016

Mon. Not. R. Astron. Soc.

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We present spectroscopic and photometric solutions for three spotted systems with red giant components. Absolute physical and orbital parameters for these double-lined detached eclipsing binary stars are presented for the first time. These were derived from the V -, and I -band ASAS and WASP photometry, and new radial velocities calculated from high quality optical spectra we obtained with a wide range of spectrographs and using the two-dimensional cross-correlation technique (TODCOR). All of the investigated systems (ASAS J184949-1518.7, BQ Aqr, and V1207 Cen) show the differential evolutionary phase of their components consisting of a main sequence star or a subgiant and a red giant, and thus constitute very informative objects in terms of testing stellar evolution models. Additionally, the systems show significant chromospheric activity of both components. They can be also classified as classical RS CVn-type stars. Besides the standard analysis of radial velocities and photometry, we applied spectral disentangling to obtain separate spectra for both components of each analysed system which allowed for a more detailed spectroscopic study. We also compared the properties of red giant stars in binaries that show spots, with those that do not, and found that the activity phenomenon is substantially suppressed for stars with Rossby number higher than ∼1 and radii larger than ∼20 R ⊙ .

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Section: Spectral Analysissupporting

confidence: 62%

Orbital and physical parameters of eclipsing binaries from the ASAS catalogue – IX. Spotted pairs with red giants

Ratajczak

Hełminiak

Konacki

et al. 2016

Mon. Not. R. Astron. Soc.

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“…There is one free parameter (α), so for the abundance to be 264 significant at the 3-σ level ∆χ 2 = χ 2 (α opt ) − χ 2 (0) must be less than -9 265 (Press et al, 1992). In the case of no significant minimum, the 3-σ upper (2002) and Lellouch et al (2002) • If the chlorine source is from comets, a solar Cl/O ratio of 6.9 × 10 −4 299 is reasonable (Grevesse et al, 2007), implying a chlorine flux of 2.8 × 300 10 3 molecules/cm 2 /s. IDPs and micrometeorites can be discounted 301 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 as they would not result in sufficient CO production, but would also 302 provide a similar chlorine flux.…”

Section: Hcl Upper Limits 254mentioning

confidence: 96%

“…HCl 3 abundance is expected to be extremely variable throughout the atmospheric 4 column and will depend strongly on local atmospheric conditions and the 5 nature of the source reservoir. At the most basic level, Jupiter's bulk chlo-6 rine abundance can be estimated from the solar chlorine to hydrogen ratio of 7 3.2×10 −6 (Grevesse et al, 2007) combined with the observation that Jupiter 8 is enriched in heavy elements, such as carbon, relative to the solar compo-9 sition by a factor of about four (Niemann et al, 1998;Wong et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Constraints on Jupiter׳s stratospheric HCl abundance and chlorine cycle from Herschel/HIFI

Teanby

Showman

Fletcher

et al. 2014

Planetary and Space Science

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Detection of HCl on Jupiter would provide insight into the chlorine cycle and external elemental fluxes on giant planets, yet so far has not been possible. Here we present the most sensitive search for Jupiter's stratospheric HCl to date using observations of the 625.907 and 1876.221 GHz spectral lines with Herschel's HIFI instrument. HCl was not detected, but we determined the most stringent upper limits so far, improving on previous studies by two orders of magnitude. If HCl is assumed to be uniformly mixed, with a constant volume mixing ratio above the 1 mbar pressure level and has zero abundance below, we obtain a 3-sigma upper limit of 0.056 ppb; in contrast, if we assume uniform mixing above the 1~mbar level and allow a non-zero but downward-decreasing abundance from 1~mbar to the troposphere based on eddy diffusion, we obtain a 3-sigma upper limit of 0.024 ppb. This is below the abundance expected for a solar composition source, such as comets, and implies that upper atmosphere HCl loss processes are important. We investigated aerosol scavenging using a simple diffusion model and conclude that it could be a very effective mechanism for HCl removal. Transient scavenging by stratospheric NH3 from impacts is another potentially important loss mechanism. This suggests that it is extremely unlikely that HCl is present in sufficient quantities to be detectable in the near future. We summarise the implications for Jupiter's chlorine cycle and conclude that based on a combination of our observations and previous studies of external oxygen supply, a solar composition external source for Jupiter's chlorine combined with stratospheric scavenging by aerosols and NH3 appears the most plausible. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 AbstractDetection of HCl on Jupiter would provide insight into the chlorine cycle and external elemental fluxes on giant planets, yet so far has not been possible. Here we present the most sensitive search for Jupiter's stratosphericHCl to date using observations of the 625.907 and 1876.221 GHz spectral lines with Herschel's HIFI instrument. HCl was not detected, but we determined the most stringent upper limits so far, improving on previous studies by two orders of magnitude. If HCl is assumed to be uniformly mixed, with a constant volume mixing ratio above the 1 mbar pressure level and has zero abundance below, we obtain a 3-σ upper limit of 0.056 ppb; in contrast, if we assume uniform mixing above the 1 mbar level and allow a non-zero but downward-decreasing abundance from 1 mbar to the troposphere based on eddy diffusion, we obtain a 3-σ upper limit of 0.024 ppb. This is below the abundance expected for a solar composition source, such as comets, and 6 Herschel is an ESA space observatory with science instruments provided by Europeanled Principal Investigator consortia and wit...

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“…They found oxygen and nitrogen gradients essentially flat, and in good agreement with our results (see Table5 The comparison between the H ii region and blue supergiant populations is extremely interesting because they both are young populations and should trace the same epoch in the galaxy lifetime. In the upper panel of Figure 4 we plotted the metallicity of the supergiants of Kudritzki et al (2016) and of our H ii regions -reported on the Solar scale (12+log(O/H)=8.66; Grevesse et al 2007)-versus the galactocentric distance. We have plotted the whole sample of Kudritzki et al (2016) without removing the possible outliers.…”

Section: Radial Abundance Gradients In Ngc 55mentioning

confidence: 99%

NGC 55: a disc galaxy with flat abundance gradients

Magrini

Gonçalves

Vajgel

2016

Mon. Not. R. Astron. Soc.

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We present new spectroscopic observations obtained with GMOS@Gemini-S of a sample of 25 H ii regions located in NGC 55, a late-type galaxy in the nearby Sculptor group. We derive physical conditions and chemical composition through the T e -method for 18 H ii regions, and strong-line abundances for 22 H ii regions. We provide abundances of He, O, N, Ne, S, Ar, finding a substantially homogenous composition in the ionised gas of the disc of NGC 55, with no trace of radial gradients. The oxygen abundances, both derived with T e -and strong-line methods, have similar mean values and similarly small dispersions: 12+log(O/H)=8.13±0.18 dex with the former and 12+log(O/H)=8.17±0.13 dex with the latter. The average metallicities and the flat gradients agree with previous studies of smaller samples of H ii regions and there is a qualitative agreement with the blue supergiant radial gradient as well. We investigate the origin of such flat gradients comparing NGC 55 with NGC 300, its companion galaxy, which is also twin of NGC 55 in terms of mass and luminosity. We suggest that the differences in the metal distributions in the two galaxies might be related to the differences in their K-band surface density profile. The flatter profile of NGC 55 probably causes in this galaxy higher infall/outflow rates than in similar galaxies. This likely provokes a strong mixing of gas and a re-distribution of metals.

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The Solar Chemical Composition

Cited by 731 publications

References 31 publications

Orbital and physical parameters of eclipsing binaries from the ASAS catalogue – IX. Spotted pairs with red giants

Orbital and physical parameters of eclipsing binaries from the ASAS catalogue – IX. Spotted pairs with red giants

Constraints on Jupiter׳s stratospheric HCl abundance and chlorine cycle from Herschel/HIFI

NGC 55: a disc galaxy with flat abundance gradients

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