- ID:
- ivo://CDS.VizieR/J/AcA/59/69
- Title:
- ubvy{beta} photometry of stars in NGC 7062
- Short Name:
- J/AcA/59/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of spectroscopic and photometric observations of ten delta Sct stars and one eclipsing binary in the open cluster NGC 1817, and of ten delta Sct stars and two other variables in the open cluster NGC 7062. For all targets in NGC 1817 and for three targets in NGC 7062 the radial velocity and projected rotational velocity are determined. For all stars the effective temperature and surface gravity is measured.
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- ID:
- ivo://CDS.VizieR/J/A+AS/128/573
- Title:
- ubvy{Delta}a photometry of Renson stars
- Short Name:
- J/A+AS/128/573
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of 131 stars from Renson's (1991, Cat. <III/162>) catalogue of Ap and Am stars observed with the {Delta}-a system are presented. With few exceptions the probability division of Renson for membership in the CP2 group of peculiar stars is nicely reflected by peculiar values of {Delta}-a. Comparison with already available {Delta}-a values yields slightly larger values due to a minor shift in the g_1_ filter sampling the depression. For a description of the {Delta}-a and Stroemgren photometric system, see e.g. <GCPD/75> and <GCPD/04>, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/426/827
- Title:
- ubvyH{beta} photometry in NGC 1817 / 1807
- Short Name:
- J/A+A/426/827
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue of accurate uvby-H{beta} and J2000 coordinates for 7842 stars in an area of 65'x40' around NGC 1817. We mark the selection of probable members of NGC 1817, combining this photometric study with the previous astrometric analysis (Balaguer-Nunez et al. 2004, Cat. <J/A+A/426/819>). Also given is the cross-identification of stars in common with the astrometry (Balaguer-Nunez et al. 2004, Cat. <J/A+A/426/819>), WEBDA (http://obswww.unige.ch/WEBDA), Hipparcos (ESA, 1997, Cat. <I/239>), Tycho-2 (Hog et al., 2000, Cat. <I/250>) and USNO-A2 (Monet et al., 1998, Cat. <I/252>) catalogues.
- ID:
- ivo://CDS.VizieR/J/A+A/340/196
- Title:
- ubvyHbeta photometry of AB Cas
- Short Name:
- J/A+A/340/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 contents 471 simultaneous measurements collected in each of the four uvby colours of the Stroemgren photometric system for the eclipsing binary system AB Cas. Because of an instrumental problem, 82 points in the b channel (during the last observational night) had to be rejected (the corresponding magnitudes are listed as 0.0000). The data are magnitude differences (Du,Dv,Db,Dy) of the variable star minus comparison star in the instrumental system versus Heliocentric Julian Day. Table 2 is the same, but for H{beta} (80 points). The comparison star is BD+70 0188. The origin in time is the Julian Day 2447117. The observations were carried out (by E. Rodriguez, A. Claret, J.L. Sedano, J.M. Garcia and R. Garrido) during 1987 and 1988 using the 0.90m telescope at the Sierra Nevada Observatory, Spain.
- ID:
- ivo://CDS.VizieR/J/A+A/525/A16
- Title:
- ubvy light curves of CP stars in open clusters
- Short Name:
- J/A+A/525/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric variability of chemically peculiar (CP) stars of the upper main sequence is closely connected to their local stellar magnetic field and their rotational period. Long term investigations, as presented here, help us to identify possible stellar cycles (as in the Sun). Photoelectric Stroemgren uvby time series for 27 CP stars within the boundaries of open clusters are presented. Our observations cover a time period of about six years (1986 to 1992) with typically fifteen measurements for each objects. These observations help us to determine the rotational periods of these objects. We established, for the first time, variability for fourteen CP stars. For additional two stars, a merging of already published data sets, resulted in more precise periods, whereas for six objects, the published periods could be confirmed. Last, but not least, no significant variations were found for five stars. Apart from six stars, all targets seem to be members of their host open clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/364/205
- Title:
- UBVy photometry of cool stars
- Short Name:
- J/A+A/364/205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision photometry, high- and medium-resolution spectroscopy for a sample of 32 stars likely to be the optical counterparts of X-ray sources serendipitously detected by the EXOSAT satellite. Using also recent results from the Hipparcos satellite, we infer spectral types, compute X-ray luminosities and Li abundances and investigate the single or binary nature of the sample stars. We found eleven new variable stars, whose photometric periods fall in the 1.2-27.5 day range, for most of which the optical variability is consistent with the presence of photospheric cool spots. For our sample of X-ray selected stars we confirm the existence of a strong correlation between the stellar rotation rate and the level of activity, and also between the X-ray and bolometric luminosities. Two stars in our sample are likely to be pre-main sequence objects, one is likely to be a previously unknown M-type star within 25pc.
- ID:
- ivo://CDS.VizieR/J/A+AS/128/139
- Title:
- ubvy photometry of CR Cas
- Short Name:
- J/A+AS/128/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table contains the differential magnitudes of CR Cas respect to comparison star SAO35044 indicating the time (Julian Date) a nd magnitudes in Stroemgren filters u, v, b, y
- ID:
- ivo://CDS.VizieR/J/A+A/364/455
- Title:
- ubvy photometry of LMC/SMC B stars
- Short Name:
- J/A+A/364/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The individual reddenings for B stars in two fields in the Small Magellanic Cloud (SMC) and two fields in the Large Magellanic Cloud (LMC) are determined by means of Stroemgren uvby CCD photometry. In both LMC fields we find a foreground reddening of E(B-V)=0.085+/-0.02, and for the SMC fields we find E(B-V)=0.070+/-0.02. In addition to the foreground reddening we find contributions from reddening intrinsically in the Clouds up to E(B-V)~0.21. The intrinsic contribution is not correlated with position within our ~6'x4.5' CCD fields but varies in an essentially random way. Unless the reddening is measured for a particular object, it will be uncertain by +/-0.035 (best case, far from the central bars) to more than +/-0.10 (close to the central bars). The Stroemgren uvby photometry has been used to derive metallicities for GK giant stars in the observed fields. Adopting average reddenings we obtain mean metallicities which are consistent with those found from spectroscopic studies of F and G supergiants (Westerlund, 1997, The Magellanic Clouds, Cambridge University Press), but with a considerable scatter in the derived metallicities, from [Fe/H]=~-2.0 to [Fe/H]>0. A significant fraction of the scatter is, however, due to reddening variations rather than being intrinsic. The possible existence of high metallicity stars should be investigated further using spectroscopic methods.
- ID:
- ivo://CDS.VizieR/J/A+A/435/1099
- Title:
- ubvy photometry of 4 magnetic CP stars
- Short Name:
- J/A+A/435/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby observations from the Four College Automated Photoelectric Telescope are presented for the magnetic Chemically Peculiar (mCP) stars HD 32633, Aur, 49 Cam, and 3 Hya. We find for over 30 years, these four stars with stable optical region light curves have had constant periods of 6.4300, 3.61868, 4.28679, and 11.305 days, respectively.
- ID:
- ivo://CDS.VizieR/J/A+AS/103/1
- Title:
- ubvy Photometry of magnetic CP stars
- Short Name:
- J/A+AS/103/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope of four magnetic Chemically Peculiar stars are presented. We refined the period of 63 And to 4.1890 days. The period of the sharp-lined Si star HD 192913 is 16.840 days, a value close to, but slightly different from published values. HR 8240, a sharp-lined Si star, is found not to be a photometric variable. Comparison of four color photometry of 108 Aqr by Morrison and Wolff and from the Four College APT indicates that subtle changes in the shapes of the light curves, especially that for u, have occurred suggesting that this star may be precessing.
