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1891. Ca,by photometry in globular clusters. I. M22
ID:
ivo://CDS.VizieR/J/ApJS/219/7
Title:
Ca,by photometry in globular clusters. I. M22
Short Name:
J/ApJS/219/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the multiple stellar populations in one of the peculiar globular clusters (GCs), M22, using new ground-based wide-field Ca by and Hubble Space Telescope Wide-Field Camera 3 photometry with equivalent passbands, confirming our previous result that M22 has a distinctive red giant branch (RGB) split mainly due to the difference in metal abundances. We also make use of radial velocity measurements by others of the large number of cluster membership stars. Our main results are the following. (1) The RGB and the subgiant branch number ratios show that the calcium-weak (Ca-w) group is the dominant population of the cluster. However, an irreconcilable difference can be seen in the rather simple classification into two horizontal branches by others. (2) Each group has its own CN-CH anticorrelation. However, the alleged CN-CH positive correlation is likely illusory. (3) The location of the RGB bump of the calcium-strong (Ca-s) group is significantly fainter, which may pose a challenge to the helium enhancement scenario in the Ca-s group. (4) The positions of the centers are similar. (5) The Ca-w group is slightly more centrally concentrated, whereas the Ca-s is more elongated at larger radii. (6) The mean radial velocities for both groups are similar, but the Ca-s group has a larger velocity dispersion. (7) The Ca-s group rotates faster. The plausible scenario for the formation of M22 is that it formed via a merger of two GCs in a dwarf galaxy environment and accreted later to our Galaxy.
1892. CaII absorbers in SDSS QSOs
ID:
ivo://CDS.VizieR/J/MNRAS/444/1747
Title:
CaII absorbers in SDSS QSOs
Short Name:
J/MNRAS/444/1747
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a survey for CaII {lambda}{lambda}3934,3969 absorption-line systems culled from ~95000 Sloan Digital Sky Survey (SDSS) Data Release 7 and Data Release 9 quasar spectra. With 435 doublets identified in the catalogue, this list is the largest CaII catalogue compiled to date, spanning redshifts z<1.34, which corresponds to the most recent ~8.9Gyr of the history of the Universe. We derive statistics on the Caii rest equivalent width distribution and incidence. We find that the {lambda}3934 rest equivalent width (W_0_^{lambda}3934^) distribution cannot be described by a single exponential function. A double exponential function is required to produce a satisfactory description.
1893. CaII and H{alpha} data for dK5/dM4 stars
ID:
ivo://CDS.VizieR/J/MNRAS/421/3189
Title:
CaII and H{alpha} data for dK5/dM4 stars
Short Name:
J/MNRAS/421/3189
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use 665 high-resolution spectra for 60 different dM4 stars and 1088 high-resolution spectra for 97 different dK5 stars from the European Southern Observatory (ESO) and Observatoire de Haute Provence (OHP) data bases. We present 179 new measurements of the CaII resonance lines and 615 new measurements of the H{alpha} line for dM4 stars. We also present 701 new measurements of the CaII resonance lines and 1088 new measurements of the H{alpha} line for dK5 stars. We also compiled other measurements available in the literature.
1894. CaII and MgII excess flux density in cool stars
ID:
ivo://CDS.VizieR/J/A+A/177/131
Title:
CaII and MgII excess flux density in cool stars
Short Name:
J/A+A/177/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
The relation between the CaII H and K line-tore flux density and rotation period is studied for a sample of 313 cool stars of luminosity classes ranging from II-III to V, and compared to similar relations for MgII h and k and soft X-ray.
1895. CaII equivalent widths of dM1 stars
ID:
ivo://CDS.VizieR/J/MNRAS/426/1591
Title:
CaII equivalent widths of dM1 stars
Short Name:
J/MNRAS/426/1591
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 187 high-resolution spectra for 62 different M1 dwarfs from observations obtained with the FIbre-fed Echelle Spectrograph (FIES) on the Nordic Optical Telescope (NOT) and from observations with the Fibre-fed Extended Range Echelle Spectrograph (FEROS) from the European Southern Observatory (ESO) data base. We also compiled other measurements available in the literature.
1896. CaII H and K filter photometry II.
ID:
ivo://CDS.VizieR/J/AJ/109/2828
Title:
CaII H and K filter photometry II.
Short Name:
J/AJ/109/2828
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalog of 1990 stars on the Caby system is presented. The sample includes stars covering an extensive range in spectral type, luminosity class, and metallicity, as well as apparent magnitude. The hk indices are on the standard system defined in Anthony-Twarog et al. (1991AJ....101.1902A), while the V and (b-y) indices have been transformed to the system of Olsen (1993A&AS..102...89O), superseding the values in the original catalog of standard stars.
1897. CaII H and K filter photometry III.
ID:
ivo://CDS.VizieR/J/AJ/116/1922
Title:
CaII H and K filter photometry III.
Short Name:
J/AJ/116/1922
Date:
21 Oct 2021
Publisher:
CDS
Description:
New photometry on the uvby Ca system is presented for over 300 stars. When combined with previous data, the sample is used to calibrate the metallicity dependence of the hk index for cooler, evolved stars. The metallicity scale is based upon the standardized merger of spectroscopic abundances from 38 studies since 1983, providing an overlap of 122 evolved stars with the photometric catalog. The hk index produces reliable abundances for stars in the [Fe/H] range from -0.8 to -3.4, losing sensitivity among cooler stars due to saturation effects at higher [Fe/H], as expected.
1898. Ca II H and K Measurements Made at MWO
ID:
ivo://CDS.VizieR/III/159A
Title:
Ca II H and K Measurements Made at MWO
Short Name:
III/159A
Date:
21 Oct 2021
Publisher:
CDS
Description:
Summaries are presented of the photoelectric measurements of stellar CaII H and K line intensity made at Mount Wilson Observatory during the years 1966-1983. These results are derived from 65,263 individual observations of 1296 stars. For each star, for each observing season, the maximum, minimum, mean, and variation of the instrumental H and K index "S" are given, as well as a measurement of the accuracy of observation. A total of 3110 seasonal summaries are reported. These observations were obtained with two instruments, HKP-1 and HKP-2. The HKP-2 instrument is a four-channel chopping spectrometer which records counts in 1.09{AA} FWHM triangular bandpasses centered in the H and K lines as well as in two 20{AA} reference bandpasses centered on 3901.067 and 4001.067{AA}. The stellar activity is expressed by the index S defined as S = {alpha} (Nh+Nk)/(Nr+Nv) where Nh and Nk are the counts (corrected from background) in the H and K lines, Nr and Nv those in the reference continuum bandpasses, and {alpha} is a constant of proportionality used to correct for night-to-night instrumental variations. Higher values of S generally correspond to higher levels of chromospehric activities. Factors which effect the ability to detect stellar activity variations and accurately measure their amplitudes such as the accuracy of the H and K measurements and scattered light contamination are discussed. Relations are given which facilitate intercomparison of "S" values with residual intensities from ordinary spectrophotometry, and for converting measurements to absolute fluxes.
1899. CaII HK emission in rapidly rotating stars
ID:
ivo://CDS.VizieR/J/A+A/493/1099
Title:
CaII HK emission in rapidly rotating stars
Short Name:
J/A+A/493/1099
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present measurements of chromospheric CaII H&K activity for 481 solar-like stars. To determine the activity we used the Mount Wilson method and a newly developed method which allows to also measure CaII H&K emission features in very rapidly rotating stars. The new technique determines the activity by comparing the line shapes from known inactive slowly rotating template stars that have been artificially broadened to spectra of rapid rotators. We have analyzed solar-like stars ranging from T_eff}=5000 to 7800K with rotational velocities up to 190km/s in our sample of FOCES and FEROS spectra. The effects of the rotational broadening on the two methods have been quantified. Our method has proven to produce consistent results where S-Index values are available and offers the possibility to measure the chromospheric activity at the onset of the solar-like dynamo.
1900. CaII H&K to CaII IRT echelle spectra
ID:
ivo://CDS.VizieR/J/A+AS/146/103
Title:
CaII H&K to CaII IRT echelle spectra
Short Name:
J/A+AS/146/103
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is the third paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. High resolution echelle spectra including all the optical chromospheric activity indicators from the CaII H&K to CaII IRT lines are analysed here for 16 systems. The chromospheric contribution in these lines has been determined using the spectral subtraction technique. Very broad wings have been found in the subtracted H{alpha} profile of the very active star HU Vir. These profiles are well matched using a two-component Gaussian fit (narrow and broad) and the broad component can be interpreted as arising from microflaring. Red-shifted absorption features in the H{alpha} line have been detected in several systems and excess emission in the blue wing of FG UMa was also detected. These features indicate that several dynamical processes, or a combination of them, may be involved. Using the E_H{alpha}_/E_H{beta}_ ratio as a diagnostic we have detected prominence-like extended material viewed off the limb in many stars of the sample, and prominences viewed against the disk at some orbital phases in the dwarfs OU Gem and BF Lyn. The He I D_3_ line has been detected as an absorption feature in mainly all the giants of the sample. Total filling-in of the He I D_3_, probably due to microflaring activity, is observed in HU Vir. Self-absorption with red asymmetry is detected in the CaII H&K lines of the giants 12 Cam, FG UMa and BM CVn. All the stars analysed show clear filled-in CaII IRT lines or even notable emission reversal. The small values of the E_8542_/E_8498_ ratio we have found indicate CaII IRT emission arises from plage-like regions. Orbital phase modulation of the chromospheric emission has been detected in some systems, in the case of HU Vir evidence of an active longitude area has been found.

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