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- ID:
- ivo://CDS.VizieR/J/A+AS/102/89
- Title:
- uvby-beta Photometry of G5 stars
- Short Name:
- J/A+AS/102/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/394/479
- Title:
- uvby{beta} photometry of h and chi Per
- Short Name:
- J/A+A/394/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD uvby{beta} photometry for stars in the nuclei of the young double cluster {h} and {chi} Persei. We find that the reddening is highly variable through the {h} Per nucleus, increasing from west to east, with values ranging from E(b-y)=0.328+/-0.022 in the western part to E(b-y)=0.465+/-0.025 in the south-east. Towards {chi} Persei the reddening is fairly constant, with E(b-y)=0.398+/-0.025. Both clusters share a common distance modulus of 11.7+/-0.1mag, and an age of logt=7.10+/-0.05 years.
- ID:
- ivo://CDS.VizieR/J/A+A/373/625
- Title:
- uvby{beta} photometry of lambda Bootis stars
- Short Name:
- J/A+A/373/625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lambda Bootis stars comprise only a small number of all A-type stars and are characterized as nonmagnetic, Population I, late B to early F-type dwarfs which show significant underabundances of metals whereas the light elements (C, N, O and S) are almost normal abundant compared to the Sun. In the second paper on a spectroscopic survey for lambda Bootis stars, we present the spectral classifications of all program stars observed. These stars were selected on the basis of their Stromgren uvbybeta colors as lambda Bootis candidates. In total, 708 objects in six open clusters, the Orion OB1 association and the Galactic field were classified. In addition, nine serendipity non-candidates in the vicinity of our program stars as well as 15 Guide Star Catalogue stars were observed resulting in a total of 732 classified stars. The 15 objects from the Guide Star Catalogue are part of a program for the classification of apparent variable stars from the Fine Guidance Sensors of the Hubble Space Telescope. A grid of 105 MK standard as well as ``pathological'' stars guarantees a precise classification. A comparison of our spectral classification with the extensive work of Abt & Morrell (1995, Cat. <J/ApJS/99/135>) shows no significant differences. The derived types are 0.23+/-0.09 (rms error per measurement) subclasses later and 0.30+/-0.08 luminosity classes more luminous than those of Abt & Morrell (1995, Cat. <J/ApJS/99/135>)) based on a sample of 160 objects in common. The estimated errors of the means are +/-0.1 subclasses. The characteristics of our sample are discussed in respect to the distribution on the sky, apparent visual magnitudes and Stromgren uvbybeta colors. Table 2 lists all observed Galactic field stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/97/951
- Title:
- uvby-beta photometry of metal-poor stars
- Short Name:
- J/A+AS/97/951
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A second catalogue of uvby-beta photometry for 553 high-velocity stars is given; nearly all of these stars come from the Lowell Proper Motion Survey. These data have been taken and reduced using the same photometer, same observing techniques, same standard stars and photometric values, and same reduction programs as the "northern" observations of the first catalogue (Paper I). The errors of these data are very similar to those of the previous catalogue; for most stars the mean errors of V, m1, c1 and beta are less than +/- 0.008 mag., and less than +/- 0.005 mag. for b-y.
- ID:
- ivo://CDS.VizieR/J/A+AS/117/317
- Title:
- uvby-beta photometry of metal-poor stars. VIII.
- Short Name:
- J/A+AS/117/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of uvby-{beta} photometry for 87 of the turn-off and subgiant stars from the HK survey of Beers et al. (1992AJ....103.1987B, BPSII) is given. Most of these stars have [Fe/H]<=2.5. These photometric data have been taken and reduced using the same techniques as in our previous two uvby-{beta} catalogues (Schuster et al., 1989, Cat. <II/180> and Schuster et al., 1993, Cat. <J/A+AS/97/951>). An error analysis has been made; typical mean observational errors for a star with V=14.2m are 0.008, 0.007, 0.011, 0.010 and 0.012 in V, (b-y), m_1_, c_1_ and {beta}, respectively. Our photometric data are also compared to the UBV photometry and spectral indices from the HK survey; satisfactory agreement is found indicating good quality for the two data sets. The stars are classified in reddening-free diagrams of the uvby-{beta} system; several of the stars are found to have been mis-classified in the HK survey. Two metal-poor supergiants, three (possibly four) horizontal branch stars, one blue subluminous star and two stars with ambiguous photometry have been identified. Stellar parameters, such as E(b-y), M_V_, {delta}M_V_, and T_eff_, plus error estimates for these parameters, are provided using our photometric calibrations. Although all stars have galactic latitudes |b|>=30{deg} many of them are significantly reddened with E(b-y) ranging from 0.02 to 0.15. The average reddening towards the South Galactic Pole region, b<-60{deg}, is E(b-y)=0.027+/-0.004 corresponding to E(B-V)=0.036+/-0.005 in contrast to the low value of E(B-V)~0.01 derived from the Burstein & Heiles (1982AJ.....87.1165B) maps. The stars are analyzed in the (b-y)_0_, [Fe/H] diagram, and individual ages estimated using the isochrones of VandenBerg & Bell (1985ApJS...58..561V) and of Bergbusch & VandenBerg (1992ApJS...81..163B). These very metal-poor stars are found to be coeval, within 1-2Gyr, with the halo and thick-disk stars studied previously, with a mean age in excess of 18Gyr. Several blue "thick-disk" stars, which are perhaps analogous to the "blue metal-poor" stars of Preston et al. (1994, Cat. <J/AJ/108/538>), have been identified.
- ID:
- ivo://CDS.VizieR/J/MNRAS/358/66
- Title:
- uvby{beta} photometry of NGC 663
- Short Name:
- J/MNRAS/358/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD uvby{beta} photometry for stars in the central area of the young open cluster NGC 663. We find that the reddening is highly variable, with values ranging from E(b-y)=0.639+/-0.032 in the central part to E(b-y)=0.555+/-0.038 in the south-east. The distance modulus is found to be 11.6+/-0.1mag. (2.1kpc), and the age logt=7.25+/-0.1 years (25+7/-5Myr).
- ID:
- ivo://CDS.VizieR/J/A+AS/104/9
- Title:
- uvby-beta photometry of stars in SA 194
- Short Name:
- J/A+AS/104/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/100/571
- Title:
- uvby-beta photometry of SX Phe stars
- Short Name:
- J/A+AS/100/571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/145/187
- Title:
- uvby-{beta} photometry of WTTS
- Short Name:
- J/A+AS/145/187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present uvby-{beta} photometry of 116 X-ray flux-selected active stars in the directions of the Orion (40), Taurus-Auriga (58) and Scorpius OB2-2 (18) star forming regions. Additionally, we give near IR JHK photometry of 20 active stars in the Taurus-Auriga direction. The program stars were selected from the ROSAT All Sky Survey and EINSTEIN X-ray surveys and are spectroscopically confirmed weak-line T Tauri stars and weak-line T Tauri star candidates. The photometry confirms the young nature of the program stars and also indicates that a significant fraction of the sample could be foreground objects. The data given here probably represent the largest homogeneous uvby-{beta} photometric sample of new WTTS and WTTS candidates. Many objects in the sample are observed photometrically for the first time.
