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61. Ab initio EOS for hydrogen-helium mixtures
ID:
ivo://CDS.VizieR/J/ApJ/774/148
Title:
Ab initio EOS for hydrogen-helium mixtures
Short Name:
J/ApJ/774/148
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using density functional molecular dynamics simulations, we determine the equation of state (EOS) for hydrogen-helium mixtures spanning density-temperature conditions typical of giant-planet interiors, ~0.2-9g/cm3 and 1000-80000K for a typical helium mass fraction of 0.245. In addition to computing internal energy and pressure, we determine the entropy using an ab initio thermodynamic integration technique. A comprehensive EOS table with 391 density-temperature points is constructed and the results are presented in the form of a two-dimensional free energy fit for interpolation. Deviations between our ab initio EOS and the semi-analytical EOS model by Saumon and Chabrier (1992PhRvA..46.2084S, 1995ApJS...99..713S) are analyzed in detail, and we use the results for initial revision of the inferred thermal state of giant planets with known values for mass and radius. Changes are most pronounced for planets in the Jupiter mass range and below. We present a revision to the mass-radius relationship that makes the hottest exoplanets increase in radius by ~0.2 Jupiter radii at fixed entropy and for masses greater than ~0.5 Jupiter mass. This change is large enough to have possible implications for some discrepant "inflated giant exoplanets."
62. Ab initio EOS for water-hydrogen mixtures
ID:
ivo://CDS.VizieR/J/ApJ/806/228
Title:
Ab initio EOS for water-hydrogen mixtures
Short Name:
J/ApJ/806/228
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from ab initio simulations of liquid water-hydrogen mixtures in the range from 2 to 70GPa and from 1000 to 6000K, covering conditions in the interiors of ice giant planets and parts of the outer envelope of gas giant planets. In addition to computing the pressure and the internal energy, we derive the Gibbs free energy by performing a thermodynamic integration. For all conditions under consideration, our simulations predict hydrogen and water to mix in all proportions. The thermodynamic behavior of the mixture can be well described with an ideal mixing approximation. We suggest that a substantial fraction of water and hydrogen in giant planets may occur in homogeneously mixed form rather than in separate layers. The extent of mixing depends on the planet's interior dynamics and its conditions of formation, in particular on how much hydrogen was present when icy planetesimals were delivered. Based on our results, we do not predict water-hydrogen mixtures to phase separate during any stage of the evolution of giant planets. We also show that the hydrogen content of an exoplanet is much higher if the mixed interior is assumed.
63. Absolute Calibration of Stellar Spectrophotometry
ID:
ivo://CDS.VizieR/II/85
Title:
Absolute Calibration of Stellar Spectrophotometry
Short Name:
II/85
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalog contains the absolute fluxes for 16 stars published in Tables 1 and 2 of Johnson (1980). The absolute calibrations were accomplished by combining the 13-color photometry calibrations of Johnson and Mitchell (1975) with spectra obtained with a Michelson spectrophotometer and covering the wavelength range 4000 to 10300 Angstroms (Johnson 1977). The agreement between the absolute calibration and another recent one based upon data for alpha Lyr and 109 Vir by Tug et al. (1977) is shown (Johnson 1980) to be quite good. The catalog includes star name, cross identifications to the numbering systems of the Bright Star Catalogue and The Henry Draper Catalogue and arrays of fluxes having the same number of elements for each of the 16 stars.
64. Absolute flux distribution of BD +17 4708
ID:
ivo://CDS.VizieR/J/AJ/128/3053
Title:
Absolute flux distribution of BD +17 4708
Short Name:
J/AJ/128/3053
Date:
21 Oct 2021
Publisher:
CDS
Description:
Secondary flux standards are established by measuring their brightness relative to primary standard stars. The Hubble Space Telescope (HST) primary standards are the three pure-hydrogen white dwarf (WD) flux standards that determine the sensitivity calibration for the Space Telescope Imaging Spectrograph. STIS observations have defined the flux of the Sloan Digital Sky Survey (SDSS, http://www.sdss.org) standard BD+17 4708 from 0.17 to 1.0{mu}m with an uncertainty of less than 0.5% relative to the HST primary standards, as verified by two independent sets of photometry.
65. Absolute fluxes and distances of PN
ID:
ivo://CDS.VizieR/J/A+AS/94/399
Title:
Absolute fluxes and distances of PN
Short Name:
J/A+AS/94/399
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a complete list of averaged recalibrated absolute H{beta} fluxes, global (where possible) relative He II {lambda} 4686 fluxes, 5-GHz radio flux densities, and H{alpha}/H{beta} interstellar extinction constants for 778 Galactic planetary nebulae. The catalog provides much of the fundamental data required to generate Zanstra temperatures. When data with the lowest errors are selected, the optical and radio/optical extinctions show a peculiar correlation, with the radio values slightly high at low extinction and notably low at high extinction. The data are used, along with the best estimates of angular diameters, to calculate Shklovsky distances according to the Daub scheme on the scale used earlier by Cahn and Kaler (1971ApJS...22..319C). Use of this distance scale shows approximate equality of the death rates of optically thick and optically thin planetary nebulae. The method gives the correct distances to the Magellanic Clouds.
66. Absolute magnitude of Globular Cluster
ID:
ivo://CDS.VizieR/J/MNRAS/365/1357
Title:
Absolute magnitude of Globular Cluster
Short Name:
J/MNRAS/365/1357
Date:
21 Oct 2021
Publisher:
CDS
Description:
We test whether the peak absolute magnitude MV(TO) of the Globular Cluster Luminosity Function (GCLF) can be used for reliable extragalactic distance determination. Starting with the luminosity function of the Galactic Globular Clusters listed in Harris (Cat. <VII/202>) catalogue, we determine MV(TO) either using current calibrations of the absolute magnitude MV(RR) of RR Lyrae stars as a function of the cluster metal content [Fe/H] and adopting selected cluster samples.
67. Absolute magnitudes for late-type dwarfs
ID:
ivo://CDS.VizieR/J/AN/326/321
Title:
Absolute magnitudes for late-type dwarfs
Short Name:
J/AN/326/321
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new formula for absolute magnitude determination for late-type dwarf stars as a function of (g-r) and (r-i) for Sloan photometry (as defined by Abazajian et al., 2003AJ....126.2081A). The absolute magnitudes estimated by this approach are brighter than those estimated by colour-magnitude diagrams, and they reduce the luminosity function rather close to the luminosity function of Hipparcos.
68. Absolute magnitudes of cataclysmic variables
ID:
ivo://CDS.VizieR/J/other/NewA/12.446
Title:
Absolute magnitudes of cataclysmic variables
Short Name:
J/other/NewA/12.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using reliable trigonometric measurements, we find that the absolute magnitude of cataclysmic variables depends on the orbital period and de-reddened (J-H)_0_ and (H-Ks)_0_ colours of 2MASS (Two Micron All Sky Survey) photometric system. The calibration equation covers the ranges 0.032d<P_orb_<=0.454d, -0.08<(J-H)_0_<=1.54, -0.03<(H-Ks)_0_<=0.56 and 2.0<M_J_<11.7; It is based on trigonometric parallaxes with relative errors of ({sigma}{pi}/{pi})<=0.4. By using the period-luminosity-colours (PLCs) relation, we estimated the distances of cataclysmic variables with orbital periods and 2MASS observations and compared them with distances found from other methods. We suggest that the PLCs relation can be a useful statistical tool to estimate the distances of cataclysmic variables.
69. Absolute parameters of 509 main-sequence stars
ID:
ivo://CDS.VizieR/J/MNRAS/479/5491
Title:
Absolute parameters of 509 main-sequence stars
Short Name:
J/MNRAS/479/5491
Date:
21 Oct 2021
Publisher:
CDS
Description:
Absolute parameters of 509 main-sequence stars selected from the components of detached eclipsing spectroscopic binaries in the solar neighbourhood are used to study mass-luminosity, mass-radius, and mass-effective temperature relations (MLR, MRR, and MTR). The MLR function is found better if expressed by a six-piece classical MLR (L{prop.to}M^{alpha}^) rather than a fifth or a sixth degree polynomial within the mass range of 0.179<=M/M_{sun}_<=31. The break points separating the mass ranges with classical MLR do not appear to us to be arbitrary. Instead, the data indicate abrupt changes along the mass axis in the mean energy generation per unit of stellar mass. Unlike the MLR function, the MRR and MTR functions cannot be determined over the full range of masses. A single-piece MRR function is calibrated from the radii of stars with M<=1.5M_{sun}_, while a second single-piece MTR function is found for stars with M>1.5M_{sun}_. The missing part of the MRR is computed from the MLR and MTR, while the missing part of the MTR is computed from the MLR and MRR. As a result, we have interrelated the MLR, MRR, and MTR, which are useful in determining the typical absolute physical parameters of main-sequence stars of given masses. These functions are also useful to estimate typical absolute physical parameters from typical T_eff_ values. Thus, we were able to estimate the typical absolute physical parameters of main-sequence stars observed in the Sejong Open cluster Survey, based on that survey's published values for Teff. Since typical absolute physical parameters of main-sequence stars cannot normally be determined in such photometric surveys, the interrelated functions are shown to be useful to compute such missing parameters from similar surveys.
70. Absolute photoionization cross sections
ID:
ivo://CDS.VizieR/J/A+A/439/387
Title:
Absolute photoionization cross sections
Short Name:
J/A+A/439/387
Date:
21 Oct 2021
Publisher:
CDS
Description:
Absolute photoionization cross sections for the ions N2+, N3+, O3+, O4+, F3+ , F4+ and Ne4+ are measured using the merged-beam technique, combining the synchrotron radiation from an undulator at the storage ring ASTRID with ions produced by an ECR ion source. The files contain the experimental absolute cross-section data reported in the paper. Each ascii file has 3 columns: Photon energy (eV), Cross section (Mb) and Statistical uncertainty (Mb). In addition to the latter there is a systematic uncertainty on the cross sections of about 15%. (1Mb=10^-18^cm^2^).

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