We present CCD photometric distance estimates of 100 SCR (SuperCOSMOS RECONS) systems with {mu}>=0.18"/yr, 29 of which are new discoveries previously unpublished in this series of papers. These distances are estimated using a combination of new VRI photometry acquired at CTIO and JHK magnitudes extracted from 2MASS. The estimates are improvements over those determined using photographic plate BRI magnitudes from SuperCOSMOS plus JHK, as presented in the original discovery papers. In total, 77 of the 100 systems investigated are predicted to be within 25pc.
We discuss the selection and observations of a large sample of nearby galaxies, which we are using to quantify the star formation activity in the local Universe. The sample consists of 334 galaxies across all Hubble types from S0/a to Im and with recession velocities of between 0 and 3000km/s. The basic data for each galaxy are narrow band H{alpha}+[NII] and R-band imaging, from which we derive star formation rates, H{alpha}+[NII] equivalent widths and surface brightnesses, and R-band total magnitudes. A strong correlation is found between total star formation rate and Hubble type, with the strongest star formation in isolated galaxies occurring in Sc and Sbc types. More surprisingly, no significant trend is found between H{alpha}+[NII] equivalent width and galaxy R-band luminosity. More detailed analyses of the data set presented here will be described in subsequent papers.
The results of classical CCD observations for 371 double or multiple stars (450 pairs) obtained at both, Serbian Astronomical Station on the mountain of Vidojevica (ASV) and Bulgarian National Astronomical Observatory at Rozhen (NAOR) are presented. At ASV the observations were performed with the 0.6 m telescope in the first half of 2016 during 11 nights, and with the newly mounted 1.4 m telescope in the second half of 2016 during 16 nights. At NAOR, the observations were performed with the 2 m telescope during four nights. In this paper, we present 477 measurements (position angle and angular separation) for these 450 pairs. Among them there are 41 pairs with published orbital or linear elements and residuals are given for them. Some pairs have measurements for several epochs. Our observed pairs have angular separations in the interval from 1.60" to 190.30", with a mean angular separation of 14.87" and a median value of 4.34". Two new pairs and linear elements for four pairs which are calculated for the first time are also presented.
CCD measurements of multiple stars at NAOR and ASV
Short Name:
J/AJ/146/52
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 222 double or multiple stars were carried out during three nights in 2011. This is the sixth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2011, using the 0.6m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 208 double or multiple stars were carried out during six nights. This is the first series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper, we present the results for the position angle and angular separation for 337 pairs and residuals for 72 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.37'' to 172.81'', with a median angular separation of 7.66''. We also present the recalculated linear solutions for four pairs and one linear solution that has been calculated for the first time.
We present new astrometric and photometric data for 253 visual double stars of the "intermediate" class, i.e. with angular separations in the range 1 to 15 arcsec. The multi-colour observations were obtained in 1992-94 as part of the ESO Key Programme "Visual Double Stars" performed at La Silla Observatory (Chile). Differential magnitudes and colours have been secured in a systematic way while component magnitudes and colour indices have been determined in the V and I passbands of the Cousins standard system in good photometric conditions only. Internal and mean external errors are respectively smaller than 0.01mag and a few hundred of a magnitude (0.02 to 0.03mag). Relative positions are obtained as a by-product with internal errors of the order of 0.006arcsec in angular separation and 0.08{deg} in position angle. Final accuracies are thoroughly discussed: we illustrate the overall excellent quality of the data and estimate the quality degradation for angular separations barely larger than the width of the seeing disk.
Within the sample of six young open clusters (NGC 1502, NGC 3105, Stock 16, NGC 6268, NGC 7235 and NGC 7510) we have investigated 1753 objects using the narrow band, three filter Delta a photometric system resulting in the detection of eleven bona-fide magnetic chemically peculiar (CP) stars and five Be or metal-weak stars. The results for the distant cluster NGC 3105 is most important because of the still unknown influence of the global metallicity gradient of the Milky Way. These findings confirms that CP stars are present in open clusters of very young ages (logt>=6.90) at galactocentric distances up to 11.4kpc. For all programme clusters the age, reddening and distance modulus were derived using the corresponding isochrones. Some additional variable stars within Stock 16 could be identified by comparing different photometric studies.
The M33 galaxy is a nearby, relatively metal-poor, late-type spiral. Its proximity and almost face-on inclination means that it projects over a large area on the sky, making it an ideal candidate for wide-field CCD mosaic imaging. Photometry was obtained for more than 106 stars covering a 74'x56' field centered on M33. Main-sequence, supergiant branch, red giant branch, and asymptotic giant branch (AGB) populations are identified and classified based on broadband V and I photometry. Narrowband filters are used to measure spectral features allowing, the AGB population to be further divided into C and M star types. The galactic structure of M33 is examined using star counts, color-color, and color-magnitude-selected stellar populations. We use the C to M star ratio to investigate the metallicity gradient in the disk of M33.
