J. H. Peña, A. Arellano Ferro, R. Peña-Miller, M. Alvarez, Y. Rosas, H., García, G. Muñoz, B. Vargas, J. P. Sareyan, C. A. Guerrero, A. Rentería
We present time-series uvby-beta photometry of 41 classical Cepheid stars. A brief discussion of the comparison between the presented data and previous photometric data has been done.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
继续探索
From $uvby-β$ photometry of the open clusters NGC 6811 (75 stars), and NGC 6830 (19 stars) we were able to determine membership of the stars to each cluster, and fix the age and reddening for each. Since several short period stars have recently been found, we have carried out a study of these variables.
The study of open clusters and their short period variable stars is fundamental in stellar evolution. Because the cluster members are formed in almost the same physical conditions, they share similar stellar properties such age and chemical composition. The assumption of common age, metallicity and distance impose strong constraints when modeling an ensemble of short period pulsators belonging to open clusters (e.g. Fox Machado et al., 2006). Very recently, Luo et al. (2009) carried out a search for variable stars in the direction of NGC 6811 with CCD photometry in B and V bands. They detected…
From photoelectric $uvbyβ$ data and recent accurate synthetic and spectroscopic values of $T_{\rm eff}$ and log~$g$ for 50 F-G supergiants, we have calculated functional relationships that lead to initial estimates of effective temperature and gravities for these types of stars. It is shown that while the $T_{\rm eff}$ relationships are calculated using the data on young massive supergiants, they are also valid for evolved stars of similar temperatures like post-AGB and RV Tau stars. The gravity can also be predicted from the $Δ[c_1]$ index with an uncertainty of about 0.26 dex. Although a cle…
A new all-sky catalogue of all available uvbybeta measurements from the literature was generated. The uvbybeta photometric system is widely used for the study of various Galactic and extragalactic objects. It measures the colour due to temperature differences, the Balmer discontinuity, and blanketing absorption due to metals. The data for the individual stars were cross-checked on the basis of the Tycho-2 catalogue. This catalogue includes very precise celestial coordinates, but is magnitude and spatial resolution limited. However, the loss of objects is only marginal and is compensated for by…
Open clusters can be the key to deepen our knowledge on various issues involving the structure and evolution of the Galactic disk and details of stellar evolution because a cluster's properties are applicable to all its members. However the number of open clusters with detailed analysis from high resolution spectroscopy and/or precision photometry imposes severe limitation on studies of these objects. To expand the number of open clusters with well-defined chemical abundances and fundamental parameters, we investigate the poorly studied, anticenter open cluster Tombaugh 1. Using precision uvby…
This study analyzes 338 new times of visual, CCD, photoelectric and photographic maxima of the classical Cepheid SV Vul. The corresponding observations were made between 1913 and 2022. On this new and large observational basis, the period variations of this star of major astrophysical interest are re-visited. Without contradicting the theory or previous studies, we show that visual observations are important for a long-term monitoring of the period variations of well-selected bright Cepheids. This study establishes the period rate of change of SV Vul at -250 s/yr. Its period is currently short…
Precision CCD uvbyCaHbeta photometry is presented of the old cluster, M67, covering one square degree with typical internal precision at the 0.005-0.020 mag level to V~17. The photometry is calibrated using standards over a wide range in luminosity and temperature from NGC 752 and zeroed to the standard system via published photoelectric observations. Relative to NGC 752, differential offsets in reddening and metallicity are derived using astrometric members, supplemented by radial-velocity information. From single-star members, offsets in the sense (M67 - NGC 752) are Delta E(b-y) = -0.005 +/…
The preliminary results of new photometric observations of the $δ$ Scuti stars 7 Aql and 8 Aql are reported. 51 hr of $uvby-β$ photoelectric photometric data were obtained over the period June and July 2007 at the San Pedro Mártir Observatory, Mexico. Period analyses confirm the three pulsation modes discovered in 8 Aql in the framework of the STEPHI 2003 multisite campaign. For the star 7 Aql we were able to detect only the main pulsation modes. The standard magnitudes of both stars are obtained. The frequency, amplitude and phases of the frequency modes in different filters are presented.
A photometric UBV survey is presented for 610 stars in a region surrounding the Cepheid AQ Puppis and centered southwest of the variable, based upon photoelectric measures for 14 stars and calibrated iris photometry of photographic plates of the field for 596 stars. An analysis of reddening and distance for program stars indicates that the major dust complex in this direction is ~1.8 kpc distant, producing differential extinction described by a ratio of total-to-selective extinction of R=Av/E(B-V)=3.10+-0.20. Zero-age main-sequence fitting for the main group of B-type stars along the line of s…
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). Furthermore, these data provide a basis for detailed surface mapping techniques. Photoelectric Stroemgren uvby time series for 27 CP stars within the boundaries of open clusters are presented. In addition, Hipparcos photometric data (from 1989 to 1993) are used for our analysis. Our observations cover a time period of a…
扫码添加微信好友，提出您的宝贵建议 👇
💡 备注请填写：网站反馈
发表机构由 AI 从论文文本抽取，如发现错误，欢迎反馈修正建议。