- ID:
- ivo://CDS.VizieR/J/A+A/405/1095
- Title:
- Limb-darkening coefficients from ATLAS9 models
- Short Name:
- J/A+A/405/1095
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using up-to-date model atmospheres (Heiter et al. 2002A&A...392..619H) with the turbulent convection approach developed by Canuto, Goldman & Mazzitelli (1996ApJ...473..550C, CGM), quadratic, cubic and square root limb darkening coefficients (LDC) are calculated with a least square fit method for the Stroemgren photometric system. This is done for a sample of solar metallicity models with effective temperatures between 6000 and 8500K and with logg between 2.5 and 4.5. A comparison is made between these LDC and the ones computed from model atmospheres using the classical mixing length prescription with a mixing length parameter {alpha}=1.25 and {alpha}=0.5. For CGM model atmospheres, the law which reproduces better the model intensity is found to be the square root one for the u band and the cubic law for the v band. The results are more complex for the b and y bands depending on the temperature and gravity of the model. Similar conclusions are reached for Mixing Length Theory (MLT) {alpha}=0.5 models. As expected much larger differences are found between CGM and MLT with {alpha}=1.25. In a second part, the weighted limb-darkening integrals, b_ell_, and their derivatives with respect to temperature and gravity, are then computed using the best limb-darkening law. These integrals are known to be very important in the context of photometric mode identification of non-radial pulsating stars. The effect of convection treatment on these quantities is discussed and as expected differences in the b_ell_ coefficients and derivatives computed with CGM and MLT {alpha}=0.5 are much smaller than differences obtained between computations with CGM and MLT {alpha}=1.25. The limb darkening coefficients are given here for the u, v, b and y bands and for CGM models, MLT {alpha}=0.5 models and MLT {alpha}=1.25 models.
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- ID:
- ivo://CDS.VizieR/J/AJ/106/2096
- Title:
- Limb-darkening coefficients in binaries
- Short Name:
- J/AJ/106/2096
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present monochromatic, passband-specific, and bolometric limb-darkening coefficients for a linear as well as nonlinear logarithmic and square root limb-darkening laws. These coefficients, including the bolometric ones, are needed when modeling binary star light curves with the latest version of the Wilson-Devinney light curve program. We base our calculations on the most recent ATLAS stellar atmosphere models for solar chemical composition stars with a wide range of effective temperatures and surface gravities. We examine how well various limb-darkening approximations represent the variation of the emerging specific intensity across a stellar surface as computed according to the model. For binary star light curve modeling purposes, we propose the use of a logarithmic or a square root law. We design our tables in such a manner that the relative quality of either law with respect to another can be easily compared. Since the computation of bolometric limb-darkening coefficients first requires monochromatic coefficients, we also offer tables of these coefficients (at 1221 wavelength values between 0.09 nm and 160 {mu}m) and tables of passband-specific coefficients for commonly used photometric filters.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A14
- Title:
- Limb-darkening for CoRoT, Kepler, Spitzer
- Short Name:
- J/A+A/546/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The knowledge of how the specific intensity is distributed over the stellar disk is crucial for interpreting the light curves of extrasolar transiting planets, double-lined eclipsing binaries, and other astrophysical phenomena. To provide theoretical inputs for light curve modelling codes, we present new calculations of limb-darkening coefficients for the spherically symmetric PHOENIX models. The limb-darkening coefficients were computed by covering the transmission curves of Kepler, CoRoT, and Spitzer space missions, as well as the passbands of the Stromgren, Johnson-Cousins, Sloan, and 2MASS. These computations adopted the least-square method. In addition, we also calculated the linear and bi-parametric approximations by adopting the flux conservation method as an additional tool for estimating the theoretical error bars in the limb-darkening coefficients. Six laws were used to describe the specific intensity distribution: linear, quadratic, square root, logarithmic, exponential, and a more general one with 4 terms. The computations are presented for the solar chemical composition, with logg varying between 2.5 and 5.5 and effective temperatures between 1500K-4800K. The adopted Microturbulent velocity and the mixing-length parameters are 2.0km/s and 2.0, respectively. Model are for solar metallicity.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A16
- Title:
- Limb-darkening for CoRoT, Kepler, Spitzer. II.
- Short Name:
- J/A+A/552/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extension of our investigations on limb-darkening coefficients computed with spherical symmetrical PHOENIX models. The models investigated in this paper cover the range 5000K<=Teff<=10000K and complete our previous studies of low effective temperatures computed with the same code. The limb-darkening coefficients are computed for the transmission curves of the Kepler, CoRoT, and Spitzer space missions and the Stroemgren, Johnson-Cousins, Sloan, and 2MASS passbands. These computations were performed by adopting the least-squares method. We have used six laws to describe the specific intensity distribution: linear, quadratic, square root, logarithmic, exponential, and a general law with four terms. The computations are presented for the solar chemical composition and cover the range 3.0<=logg<=5.5. The adopted microturbulent velocity and the mixing-length parameter are 2.0km/s and 2.0.
- ID:
- ivo://CDS.VizieR/VI/154
- Title:
- Limb-darkening for Space Mission GAIA
- Short Name:
- VI/154
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- In the past few years, the number of space missions with astrophysical purposes has increased, with COROT, KEPLER, MOST and more recently TESS. Two of the most important complementary tools for these missions are the gravity and limb-darkening coefficients, hereafter GDC and LDC. For the missions mentioned above, many calculations are available to be used in several branches of stellar physics: synthetic light curves of eclipsing binaries and planetary transits, stellar diameters, line profiles in rotating stars, etc. see Claret & Bloemen (2011, Cat. J/A+A/529/A75), Claret et al. (2014, Cat. J/A+A/567/A3), Claret (2017, Cat. J/A+A/600/A30) and Claret (2018, Cat. J/A+A/618/A20). However, as noted by Zhou et al. (2018, AJ, submitted), these coefficients are not available for the GAIA mission. The main objective of this Research Note is to provide the theoretical calculations of the LDC and GDC for GAIA. We use two stellar atmosphere models: ATLAS (plane-parallel) and PHOENIX with spherical symmetry (Husser et al. 2013). The specific intensity distribution was fitted using five approaches: linear, quadratic, square root, logarithmic, and a more general one with four terms. These grids cover 19 metallicities ranging from 10^-5^ up to 10^+1^ solar abundances, 0<=logg<=6.0 and 1500K<=Teff<=50000K. The calculations of the gravity-darkening coefficients were performed for all plane-parallel ATLAS models. https://doi.org/10.3847/2515-5172/aaffdf
- ID:
- ivo://CDS.VizieR/J/A+A/618/A20
- Title:
- Limb-darkening for TESS, Kepler, Corot, MOST
- Short Name:
- J/A+A/618/A20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the biggest problems we can encounter while dealing with the limb-darkening coefficients for stellar atmospheric models with spherical symmetry is the difficulty of adjusting both the limb and the central parts simultaneously. In particular, the regions near the drop-offs are not well reproduced for most models, depending on Teff, log g, or wavelength. Even if the law with four terms is used, these disagreements still persist. Here we introduce a new method that considerably improves the description of both the limb and the central parts and that will allow users to test models of stellar atmospheres with spherical symmetry more accurately in environments such as exoplanetary transits, eclipsing binaries, etc.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A30
- Title:
- Limb-darkening for TESS satellite
- Short Name:
- J/A+A/600/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new gravity and limb-darkening coefficients for a wide range of effective temperatures, gravities, metallicities, and microturbulent velocities. These coefficients can be used in many different fields of stellar physics as synthetic light curves of eclipsing binaries and planetary transits, stellar diameters, line profiles in rotating stars, and others.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/146
- Title:
- Line-of-sight velocities from bar simulations
- Short Name:
- J/ApJ/812/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract the resonant orbits from an N-body bar that is a good representation of the Milky Way, using the method recently introduced by Molloy et al. (2015ApJ...804...80M). By decomposing the bar into its constituent orbit families, we show that they are intimately connected to the boxy-peanut shape of the density. We highlight the imprint due solely to resonant orbits on the kinematic landscape toward the Galactic center. The resonant orbits are shown to have distinct kinematic features and may be used to explain the cold velocity peak seen in the Apache Point Observatory Galactic Evolution Experiment commissioning data. We show that high velocity peaks are a natural consequence of the motions of stars in the 2:1 orbit family and that stars on other higher order resonances can contribute to the peaks. The locations of the peaks vary with bar angle and, with the tacit assumption that the observed peaks are due to the 2:1 family, we find that the locations of the high velocity peaks correspond to bar angles in the range 10{deg}<~{theta}_bar_<~25{deg}. However, some important questions about the nature of the peaks remain, such as their apparent absence in other surveys of the Bulge and the deviations from symmetry between equivalent fields in the north and south. We show that the absence of a peak in surveys at higher latitudes is likely due to the combination of a less prominent peak and a lower number density of bar supporting orbits at these latitudes.
- ID:
- ivo://CDS.VizieR/J/A+A/359/18
- Title:
- Line-strength predictions in Elliptical Galaxies
- Short Name:
- J/A+A/359/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table shows the line-strength predictions computed for: CaT, NaI, and MgI in the near infrared and Mgb, Mg2, Fe52, Fe53, NaD and H{beta}, in the blue-visible range, for Single Stellar Population (SSP) of 6 different metallicities, (Z=0.0004, 0.001, 0.004, 0.008, 0.02 and 0.05), and ages from log(age)=6.60 (4Gyr) to log(age)=10.30 (20Gyr), in steps of 0.10dex from 6.60 until 10.00, and 0.02 afterwards. (Therefore there are 50 records for each metallicity except that Z=0.001 has only 47). All indices have been computed taken the model atmospheres from Lejeune et al. (1997, Cat. <J/A+AS/125/229>, 1998, Cat. <J/A+AS/130/65>) and Clegg & Middlemass (1987MNRAS.228..759C) for hot stars (Teff > 50000 K). The used isochrones are from the Padova group (Bressan et al., 1993, Cat. <J/A+AS/100/647>). The total mass of every SSP is 10^9^M_{sun}_ with a Salpeter-type IMF, Phi(m)=m^-{alpha}^, with {alpha}=2.35, from m_low=0.6M_{sun}_ to m_up_=100M_{sun}_. The fitting functions for blue indices are those from Worthey et al. (1994, Cat. <J/ApJS/94/687>).
- ID:
- ivo://CDS.VizieR/J/ApJ/840/115
- Title:
- Local interstellar spectra of cosmic-ray species
- Short Name:
- J/ApJ/840/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Local interstellar spectra (LIS) for protons, helium, and antiprotons are built using the most recent experimental results combined with state-of-the-art models for propagation in the Galaxy and heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosmic-ray (CR) species at different modulation levels and at both polarities of the solar magnetic field. To do so in a self-consistent way, an iterative procedure was developed, where the GALPROP LIS output is fed into HelMod, providing modulated spectra for specific time periods of selected experiments to compare with the data; the HelMod parameter optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the maximum likelihood procedure using an extensive data set of proton spectra from 1997 to 2015. The proposed LIS accommodate both the low-energy interstellar CR spectra measured by Voyager 1 and the high-energy observations by BESS, Pamela, AMS-01, and AMS-02 made from the balloons and near-Earth payloads; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range.
