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2212. BSk26 functionals
- ID:
- ivo://CDS.VizieR/J/A+A/635/A84
- Title:
- BSk26 functionals
- Short Name:
- J/A+A/635/A84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the cooling process of a non-accreting neutron star, the composition and properties of the crust are thought to be fixed at the finite temperature where nuclear reactions fall out of equilibrium. A lower estimation for this temperature is given by the crystallization temperature, which can be as high as ~7x10^9^K in the inner crust, potentially leading to sizeable differences with respect to the simplifying cold-catalyzed matter hypothesis. We extend a recent work (Fatina et al., 2020, Cat. J/A+A/633/A149) on the outer crust, to the study of the crystallization of the inner crust and the associated composition in the one-component plasma approximation. The finite temperature variational equations for non-uniform matter in both the liquid and the solid phases are solved using a compressible liquid-drop approach with parameters optimized on four different microscopic models which cover the present uncertainties in nuclear modeling. We consider separately the effect of the different nuclear ingredients with their associated uncertainties, namely the nuclear equation of state, the surface properties in the presence of a uniform gas of dripped neutrons, and the proton shell effects arising from the ion single-particle structure. Our results suggest that the highest source of model dependence comes from the smooth part of the nuclear functional. We show that shell effects play an important role at the lowest densities close to the outer crust, but the most important physical ingredient to be settled for a quantitative prediction of the inner crust properties is the surface tension at extreme isospin values.
- ID:
- ivo://CDS.VizieR/J/AJ/129/809
- Title:
- B-star rotational velocities in h and {chi} Persei
- Short Name:
- J/AJ/129/809
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Projected rotational velocities (vsini) have been measured for 216 B0-B9 stars in the rich, dense h and {chi} Persei double cluster and compared with the distribution of rotational velocities for a sample of field stars having comparable ages (t~12-15Myr) and masses (M~4-15M_Sun_).
- ID:
- ivo://CDS.VizieR/J/A+A/610/A30
- Title:
- B stars in 4 open clusters
- Short Name:
- J/A+A/610/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar physical properties of star clusters are poorly known and the cluster parameters are often very uncertain. Our goals are to perform a spectrophotometric study of the B star population in open clusters to derive accurate stellar parameters, search for the presence of circumstellar envelopes, and discuss the characteristics of these stars. The BCD spectrophotometric system is a powerful method to obtain stellar fundamental parameters from direct measurements of the Balmer discontinuity. To this end, we wrote the interactive code MIDE3700. The BCD parameters can also be used to infer the main properties of open clusters: distance modulus, color excess, and age. Furthermore, we inspected the Balmer discontinuity to provide evidence for the presence of circumstellar disks and identify Be star candidates. We used an additional set of high-resolution spectra in the H{alpha} region to confirm the Be nature of these stars. We provide Teff, logg, Mv, Mbol, and spectral types for a sample of 68 stars in the field of the open clusters NGC6087, NGC6250, NGC6383, and NGC6530, as well as the cluster distances, ages, and reddening. Then, based on a sample of 230 B stars in the direction of the 11 open clusters studied along this series of three papers, we report 6 new Be stars, 4 blue straggler candidates, and 15 B-type stars (called Bdd) with a double Balmer discontinuity, which indicates the presence of circumstellar envelopes. We discuss the distribution of the fraction of B, Be, and Bdd star cluster members per spectral subtype. The majority of the Be stars are dwarfs and present a maximum at the spectral type B2-B4 in young and intermediate-age open clusters (<40Myr). Another maximum of Be stars is observed at the spectral type B6-B8 in open clusters older than 40Myr, where the population of Bdd stars also becomes relevant. The Bdd stars seem to be in a passive emission phase. Our results support previous statements that the Be phenomenon is present along the whole main sequence band and occurs in very different evolutionary states.We find clear evidence of an increase of stars with circumstellar envelopes with cluster age. The Be phenomenon reaches its maximum in clusters of intermediate age (10-40Myr) and the number of B stars with circumstellar envelopes (Be plus Bdd stars) is also high for the older clusters (40-100Myr).
- ID:
- ivo://CDS.VizieR/J/other/ApSS/203.53
- Title:
- B stars UBV and SpType catalogue
- Short Name:
- J/other/ApSS/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present work represents a catalogue of spectral classification and photometric data of 2047 B type stars using the {Delta}Q method.
2216. BT-COND
- ID:
- ivo://svo.cab/models/bt-cond
- Title:
- BT-COND
- Short Name:
- BT-COND
- Date:
- 04 Sep 2019 08:31:00
- Publisher:
- SVO CAB
- Description:
- The BT-COND Model grid of theoretical spectra. Brown dwarfs/extrasolar planets atmosphere models without irradiation and no dust opacity (no dust settling) but updated abundances. Wavelengths have been converted to air wavelengths.
2217. BT-DUSTY
- ID:
- ivo://svo.cab/models/bt-dusty
- Title:
- BT-DUSTY
- Short Name:
- BT-DUSTY
- Date:
- 04 Sep 2019 08:31:00
- Publisher:
- SVO CAB
- Description:
- The BT-DUSTY Model grid of theoretical spectra. Brown dwarfs/extrasolar planets atmosphere models without irradiation but including dust opacity (fully efficient dust settling) and updated abundances. Wavelengths have been converted to air wavelengths.
2218. BT-NextGen (AGSS2009)
- ID:
- ivo://svo.cab/models/bt-nextgen-agss2009
- Title:
- BT-NextGen (AGSS2009)
- Short Name:
- BT-NextGen-AGSS
- Date:
- 04 Sep 2019 08:31:00
- Publisher:
- SVO CAB
- Description:
- The NextGen Model grid of theoretical spectra; Gas phase only, valid for Teff > 2700 K. Updated opacities. Wavelengths have been converted to air wavelengths.
2219. BT-NextGen (GNS93)
- ID:
- ivo://svo.cab/models/bt-nextgen-gns93
- Title:
- BT-NextGen (GNS93)
- Short Name:
- BT-NextGen-GNS93
- Date:
- 04 Sep 2019 08:31:00
- Publisher:
- SVO CAB
- Description:
- The NextGen Model grid of theoretical spectra; Gas phase only, valid for Teff > 2700 K. Updated opacities. Wavelengths have been converted to air wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/51
- Title:
- B to G stars calibration in Geneva photometry
- Short Name:
- J/A+AS/122/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used recent Kurucz models and many standard stars to revise previous calibrations of the Geneva photometric parameters in terms of Teff, logg, and [M/H]. In addition, new parameters pT and pG were defined, which are the Geneva equivalents of Stromgren's a and r parameters and allow to estimate Teff and logg for stars with intermediate temperature (spectral type A0-A3). A fortran code (calib.f) has been written, which applies our calibration to stars measured in the Geneva system. A conspicuous change in slope appears in the grid d vs B2-V1. It seems to be linked with the onset of convection in the superficial layers of the star's envelope.
