- ID:
- ivo://CDS.VizieR/J/A+AS/145/275
- Title:
- uvby phot. of suspected beta Pic-like stars
- Short Name:
- J/A+AS/145/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out a Stroemgren photometric survey of thirteen southern bright stars, including {beta} Pictoris itself, during three years, d'Astrophysique de Paris, in order to detect possible weak photometric variations. {beta} Pictoris presents a small long-term variation with a change of brightness by -2.1x10^-3^mag per year, over about two years from beginning of 1996, a situation relatively similar to the one about 18 years ago. Among the other stars, only HD 38392 presents weak photometric variations with a period of 21.4 days, probably related to the star rotation period. The negative result concerning photometric variations of all other stars suggests that those stars are actually really stable and strengthens the reality of the variations discovered in the case of {beta} Pictoris and HD 38392.
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- ID:
- ivo://CDS.VizieR/J/AJ/143/5
- Title:
- uvby photometry and RVs of HD 74057
- Short Name:
- J/AJ/143/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained Stromgren b and y differential photometric observations of the solar-type eclipsing binary HD 74057 plus follow-up high-resolution, red wavelength spectroscopic observations. The system has an orbital period of 31.2198 days, a high eccentricity of 0.47, and is seen almost exactly edge on with an inclination of 89.8{deg}. The two main-sequence G0 stars are nearly identical in all physical characteristics. We used the Wilson-Devinney program to obtain a simultaneous solution of our photometric and spectroscopic observations. The resulting masses of the components are M1=1.138+/-0.003M_{sun}_ and M2=1.131+/-0.003M_{sun}_, and the radii are R1=1.064+/-0.002R_{sun}_ and R2=1.049+/-0.002R_{sun}_. The effective temperatures are 5900K (fixed) and 5843K, and the iron abundance, [Fe/H], is estimated to be +0.07. A comparison with evolutionary tracks suggests that the system may be even more metal rich. The components rotate with periods of 8.4 days, significantly faster than the predicted pseudosynchronous period of 12.7days. We see evidence that one or both components have cool spots. Both stars are close to the zero-age main sequence and are about 1.0Gyr old.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/32.143
- Title:
- uvby photometry in Baade's Window
- Short Name:
- J/other/RMxAA/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained uvby data of a sample of 232 stars in Baade's Window. These observations are presented along with the corresponding diagrams. For a description of the uvby photometric system, see e.g. <GCPD/04>
- ID:
- ivo://CDS.VizieR/J/A+A/552/A92
- Title:
- uvby photometry in NGC 7419
- Short Name:
- J/A+A/552/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The open cluster NGC 7419 is known to contain five red supergiants and a very high number of Be stars. However, there are conflicting reports about its age and distance that prevent a useful comparison with other clusters. We intend to obtain more accurate parameters for NGC 7419, using techniques different from those of previous authors, so that it may be used as a calibrator for more obscured clusters. We obtained Stroemgren photometry of the open cluster NGC 7419, as well as classification spectroscopy of ~20 stars in the area. We then applied standard analysis and classification techniques.
- ID:
- ivo://CDS.VizieR/J/MNRAS/353/310
- Title:
- uvby photometry of AB Cas
- Short Name:
- J/MNRAS/353/310
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 contents 1313 simultaneous measurements collected in each of the four uvby colours of the Stromgren photometric system for the semi-detached Algol-type eclipsing binary system AB Cas, where the primary component is a Delta Scuti-type pulsator. The data are magnitude differences (Du, Dv, Db, Dy, D(b-y), Dm1, Dc1) of the variable star minus comparison star in the standard system versus Heliocentric Julian Date. The comparison star is HD 14836. The origin in time is the Julian Day 2451108. The observations were carried out by the authors through the years 1998 and 1999 using the 0.90m telescope at Sierra Nevada Observatory, Spain. This telescope is equipped with a six-channel uvby-H{beta} spectrograph photometer for simultaneous measurements in uvby or in the narrow and wide H{beta} channels, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/401/357
- Title:
- uvby photometry of 2 Am and 2 mCP stars
- Short Name:
- J/A+A/401/357
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby observations from the Four College Automated Photoelectric Telescope (FCAPT) are presented for the metallic-lined stars 60 Tau and HR 1528 and the magnetic Chemically Peculiar stars HR 8216 and HR 8770. The first star, which is a {delta} Scuti variable, was found not to change its mean magnitudes. HR 1528 is best described as constant. A decade of photometry of HR 8216 shows that its b and y values have changed by -0.016 and -0.010mag, respectively, over this time and now can be considered a photometric variable. For HR 8770 a period of 5.3923 days is derived with the photometric variability being generally in phase. The light curves also suggest possible surface abundance inhomogeneities.
- ID:
- ivo://CDS.VizieR/J/A+AS/136/379
- Title:
- uvby photometry of 4 CP stars
- Short Name:
- J/A+AS/136/379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the magnetic CP stars 45 Leo, HR 4330, 49 Her, and HR 6718. We refined Winzer's periods for 45 Leo and HR 6718 to 1.443820 days and 0.51899days, respectively. For HR 4330 our period of 3.516 days is quite different from that of Winzer. That for 49 Her, 0.93663days, is an alias of Winzer's.
- ID:
- ivo://CDS.VizieR/J/A+AS/136/111
- Title:
- uvby photometry of 4 CP stars
- Short Name:
- J/A+AS/136/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby observations from the Four College Automated Photoelectric Telescope are presented for the mCP stars HD 35298, 19 Lyr, HD 192678, and HR 8216. The period for HD 35298 of 1.85457 days is a revision of North's value while that for 19 Lyr of 7.0980 days is alias of that found by Winzer. HD 192678 is found to be a small amplitude photometric variable with the 6.4186 day period proposed by Leroy from polarization measurements. For HR 8216, observations taken between 1995 and 1998 confirm that the star has remained constant at least since 1990.
- ID:
- ivo://CDS.VizieR/J/A+AS/146/13
- Title:
- uvby photometry of 4 CP stars
- Short Name:
- J/A+AS/146/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby observations from the Four College Automated Photoelectric Telescope (FCAPT) are presented for the mCP stars 20 Eri, HR 1297, 12 CMa, and HD 134214. Adelman & Boyce found suggestions that the light curves of 20 Eri change between observing seasons. Observations for two additional seasons confirm this behavior and lead to an improved period of 1.928890 days. For HR 1297 a new period of 15.7490 days was derived. The uvby light curves now appear to be the same for different observing seasons. 12 CMa is found to be a photometric variable with the 2.18010 day period determined from magnetic measurements by Bohlender et al. Observations of the rapidly oscillating Ap star HD 134214 confirm the lack of photometric variability which is not associated with the rapid oscillations.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/249
- Title:
- uvby photometry of 4 CP stars
- Short Name:
- J/A+AS/122/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope refine the rotational periods and define the shapes of the light curves of four magnetic Chemically Peculiar stars. HD 32633 (P=6.43000d) exhibits an in-phase variability with asymmetrically shaped light curves. 25 Sex (P=4.37900d) has a complex variability with the v, b, and y light variability crudely in phase, but quite different from that of u. HR 7224 (P=1.123095d) shows in-phase variability with two nearly equal secondary minima. HD 200311 (P=26.0042d), which was previous thought to be a long period variable, is found to be a modest photometric variable.
