- ID:
- ivo://CDS.VizieR/J/A+AS/114/253
- Title:
- uvby Photometry of Magnetic CP Stars
- Short Name:
- J/A+AS/114/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Four College Automated Photoelectric Telescope differential Stroemgren uvby photometric observations of four magnetic chemically peculiar stars are presented. One of our comparison stars was also found to be variable. Observations of the sharp-lined Si star HD 11187 are best described as representing a constant star. HD 15144 was also constant photometrically. However, its comparison star HD 14940 is definitely variable. But we were not able to find a period. It may be a {delta} Scu star. Our observations of 20 Eri and the uvby values of Renson & Manfroid show definite differences in the shapes of the light curve which suggest that this star may be undergoing a precession of its rotational axis. When we refined the period by using the minima we find a value of 1.92893 days. We refined Winzer's period of the relatively large amplitude variable HR 8933 to 2.86031 days. In v and b there are definite indications of a weak submaximum within the broad minimum.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/123/445
- Title:
- uvby photometry of metallic & Hg-Mn stars
- Short Name:
- J/A+AS/123/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby photometric observations from the 0.75-m Four College Automated Photoelectric Telescope were obtained for three metallic-line and three Mercury-Manganese stars. None were found to be variable. These sharp-lined stars may not be the best tests for class variability as their polar axes are pointed towards the earth. Each presents essentially the same visible hemisphere as it rotates.
- ID:
- ivo://CDS.VizieR/J/A+AS/133/197
- Title:
- uvby Photometry of 33 Tau, HD 50169 and HR 7786
- Short Name:
- J/A+AS/133/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the ellipsoidal variable 33 Tauri, and the magnetic Chemically Peculiar stars HD 50169 and HR 7786. We confirm that Hube's period of 2.975272 days for 33 Tau is correct. HD 50169 is a constant MCP star. HR 7786 is a large amplitude class member confirming Winzer's discovery, but its period is 8.5297 days. Its comparison star, HR 7721, a spectroscopic binary B7 V star, is variable with an amplitude of order 0.1mag, but of indeterminant period. In addition Hipparcos photometry of the comparison and check stars for early type stars whose photometry is being obtained with the FCAPT is reviewed to ascertain the stability of these stars.
- ID:
- ivo://CDS.VizieR/J/A+A/329/579
- Title:
- uvby photometry of theta CrB
- Short Name:
- J/A+A/329/579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present differential uvby photometry of {theta} CrB obtained in 1994 and 1995, complemented by Balmer line spectroscopy. This star has been constant during this period, showing no short term periodic variability with an amplitude greater than 0.005mag., nor long term variations greater than 0.01mag. The lack of variability is associated with an inactive phase of the Be star, in which no emission features are present in the spectra. The only remarkable event observed was a fading episode on JD 2449779, with an amplitude of about 0.02 magnitudes in all bandpasses and duration of 0.2-0.3 days.
- ID:
- ivo://CDS.VizieR/J/other/JAD/23.1
- Title:
- uvby photometry of theta Tucanae
- Short Name:
- J/other/JAD/23.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- theta Tucanae (HR 139, V=6.11, A7 IV) is a binary with a delta Scuti primary that was the subject of several photometric monitoring campaigns during the 1970s and again in the 1990s. The data presented in this paper were collected during an observing campaign from mid-September to the end of October 1993 at ESO La Silla, Chile, using the simultaneous Stroemgren uvby photometer at the SAT telescope during 25 partial nights. We present a time series of 1432 four-colour extinction-corrected magnitudes in the SAT instrumental system. This collection of data forms a homogeneous and contiguous dataset, obtained in one single instrumental setup, at one single observing site using one single observing protocol, and with centralized data reduction.
4366. uvby photometry of V Crt
- ID:
- ivo://CDS.VizieR/J/A+AS/101/49
- Title:
- uvby photometry of V Crt
- Short Name:
- J/A+AS/101/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/128/251
- Title:
- uvby photometry of V3903 Sgr
- Short Name:
- J/A+AS/128/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Complete uvby light curves of the young detached double-lined massive O-type eclipsing binary V3903 Sagittarii, obtained from 1989 to 1994, are presented. The observations were obtained at two different sites and a discussion of the characteristics of both data sets is included.
- ID:
- ivo://CDS.VizieR/J/A+A/389/931
- Title:
- uvby photometry & radial velocities of R 81
- Short Name:
- J/A+A/389/931
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the photometric uvby data of the eclipsing binary hypergiant R81 (B2.5 Ia-O) of the Large Magellanic Cloud. The data have been obtained with the Danish 50 cm telescope at ESO, La Silla, and cover more than one orbital cycle of 74.59 days. File table2.dat contains radial velocity measurements of photospheric lines of this star. The spectra have been obtained simultaneously with the photometry. The Feros spectrograph at the ESO 1.52m telescope was used. The quoted radial velocities are averages over the best photospheric lines.
- ID:
- ivo://CDS.VizieR/J/MNRAS/363/529
- Title:
- uvby, UBV and radial velocity of WW Aur
- Short Name:
- J/MNRAS/363/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- WW Aurigae is a detached eclipsing binary composed of two metallic- lined A-type stars orbiting each other every 2.5 days. We have determined the masses and radii of both components to accuracies of 0.4% and 0.6%, respectively. From a cross-correlation analysis of high-resolution spectra we find masses of 1.964+/-0.007M_{sun}_ for the primary star and 1.814+/-0.007M_{sun}_ for the secondary star. From an analysis of photoelectric uvby and UBV light curves we find the radii of the stars to be 1.927+/-0.011R_{sun}_ and 1.841+/-0.011R_{sun}_, where the uncertainties have been calculated using a Monte Carlo algorithm. Fundamental effective temperatures of the two stars have been derived, using the Hipparcos parallax of WW Aur and published ultraviolet, optical and infrared fluxes, and are 7960+/-420 and 7670+/-410K. The masses, radii and effective temperatures of WW Aur are only matched by theoretical evolutionary models for a fractional initial metal abundance, Z, of approximately 0.06 and an age of roughly 90Myr. This seems to be the highest metal abundance inferred for a well-studied detached eclipsing binary, but we find no evidence that it is related to the metallic-lined nature of the stars. The circular orbit of WW Aur is in conflict with the circularization timescales of both the Tassoul and the Zahn tidal theories and we suggest that this is due to pre-main-sequence evolution or the presence of a circular orbit when the stars were formed.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/529
- Title:
- UV-excess quasar candidates around NGC 450
- Short Name:
- J/A+AS/123/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the results of a survey for moderately bright quasars performed in a 20.6-square-degree field around the galaxy NGC 450. The quasar candidates we re-selected on the basis of their ultraviolet excess: by comparative visual inspection of the double image of each single object on a U/B dual-exposure Schmidt photographic plate, 95 primary and 45 secondary quasar candidates were selected on the basis of their U image being too bright. The spectroscopic identification of the primary candidates led to the discovery of 59 bona fide quasars (out of which 6 were previously known). The Palomar Schmidt plate was digitised using the MAMA measuring machine and the outcoming data reduced using ad hoc procedures. A photometric calibration allowed us to derive values for the limiting magnitudes and for the U-B index selection threshold of the survey. A catalogue containing 60 quasars is presented with accurate positions, magnitudes and additional information such as redshifts. We studied the spatial distribution of the objects and detected, for the quasars of our sample, a significant deviation from randomness in the form of a propensity to cluster in pairs on the celestial sphere with a typical scale of about 10arcmin. We also formally detected a tendency towards a 3-D clustering, but this result is induced by a single pair of quasars. A forthcoming paper will deal with a similar work performed in a field around NGC 520; the latter field is located directly to the North of the present one and slightly overlaps it.
