Results of photometric monitoring in the UBVRI bands of 5 YY Orionis stars and 2 other variable stars are presented. Each source was observed in the period of 1996, Nov. 23 to Dec. 2 and of 1996, Dec. 23 to 1997,Jan. 2 at the 1-m telescope of Wise Observatory, Israel. Tables.dat contain the luminosity variation of each star as deviation from its average observed magnitude.
We present new CCD photometry in the b and y colours of the Stroemgren uvby system for 310 stars in a 13'x13' field centered on the intermediate-age open cluster NGC 3680. Careful cross-checks indicate that previously published BV photometry of NGC 3680 is affected by random and/or systematic errors precluding its use in critical comparison with theoretical isochrone computations. Detailed notes on several individual stars are given. In addition, we present =~400 new photoelectric radial-velocity observations of 109 stars obtained with the CORAVEL scanner during the period 1988-1994. These data allow substantially complete identification of member and non-member stars in the field, and of spectroscopic binaries in both groups. Rotational velocities have also been derived for the programme stars, and our velocity variability criteria for stars of all rotations are described. The further astrophysical discussion of the data, including the definition of radial-velocity membership criteria, theoretical isochrone fitting, and the dynamical state of the cluster and the origin of its "bimodal turnoff", will appear in a separate paper (Nordstroem et al. 1996).
CCD positions for eight Jovian irregular satellites
Short Name:
J/A+A/453/349
Date:
21 Oct 2021
Publisher:
CDS
Description:
The astrometric positions of eight irregular Jovian satellites are given for the oppositions of the planet from 1995 to 1999. These positions were measured on 204 CCD frames obtained at the Cassegrain focus of a 1.6m reflector. They are compared with the theoretically calculated positions from JPL Development Ephemeris. The observed minus-calculated standard deviation for all observations of the eight satellites are {sigma}_RA_=0.071" and {sigma}_DE_=0.052". The USNO-A2.0 (<I/252>) catalog was used for the astrometric calibration.
Astrometric observations of Triton are given for the oppositions of Neptune on 1995, 1996 and two nights of 1997. In this period, 759 frames were obtained during 35 nights at the Cassegrain focus of the 1.6m and the 0.6m reflectors of the LNA-Brazil. The comparison with calculated positions gives residuals with standard deviation of the order of 0.09".
Photometric parameters for 98 early-type galaxies in the central for 11 clusters, belonging to the Ursa Major supercluster, are presented. Galaxies in the following clusters have been observed: A1270, A1291, A1377, A1318, A1383, A1436, Anon1, Anon2, Anon3, Anon4, Sh166. The derivation of the effective parameters takes the seeing into account.
We present the results of a study of streaming motion of galaxy clusters around the Giant Void (RA~13h, DE~40{deg}, z~0.11 and a diameter of 150/hMpc) in the distribution of rich Abell clusters. We used the Kormendy relation as a distance indicator taking into account galaxy luminosities. Observations were carried out in Kron-Cousins R_c_ system on the 6m and 1m telescopes of SAO RAS. For 17 clusters in a spherical shell of 25/hMpc in thickness centered on the void no significant diverging motion (expected to be generated by the mass deficit in the void) has been detected. This implies that cosmological models with low {Omega}_m_ are preferred. To explain small mass underdensity inside the Giant Void, a mechanism of void formation with strong biasing is required.
R-band surface photometry is presented for 171 late-type dwarf and irregular galaxies. For a subsample of 46 galaxies B-band photometry is presented as well. We present surface brightness profiles as well as isophotal and photometric parameters including magnitudes, diameters and central surface brightnesses. Absolute photometry is accurate to 0.1 mag or better for 77% of the sample. For over 85% of the galaxies the radial surface brightness profiles are consistent with published data within the measured photometric uncertainty. For most of the galaxies in the sample HI data have been obtained with the Westerbork Synthesis Radio Telescope. The galaxies in our sample are part of the WHISP project (Westerbork HI Survey of Spiral and Irregular Galaxies), which aims at mapping about 500 nearby spiral and irregular galaxies in HI. The availability of HI data makes this data set useful for a wide range of studies of the structure, dark matter content and kinematics of late-type dwarf galaxies.
Results of CCD photometry using V and R filters are reported for 33 RR Lyrae stars in M15. Applying the approach of Fourier decomposition of the light curves, the physical parameters of the type RRab and RRc variables were estimated. The cluster is Oosterhoff type II and the values for the iron content and distance are: [Fe/H]=-1.98+/-0.24 and d=8.67+/-0.41kpc, respectively. The mean values of the physical parameters determined for the RR Lyrae stars place the cluster precisely into the sequences Oosterhoff type - metallicity and metallicity - effective temperature, valid for globular clusters. Evidences of evolution from the ZAHB are found for the RRc but not for the RRab stars.
This catalog contains the results of a photometric survey for variable stars in a 9.4 square degree region along the galactic plane in Crux and Centaurus. A total of 300308 stars were observed at seven epochs over 42 days; 224 524 of these stars were detected at multiple epochs and were tested for possible variations in brightness that exceed observational error. 2422 stars are identified as variable at a formal confidence level of 99%; 270 of the new variables brighter than I=14.0 are classified as long period variables. A list of 242 likely short period variables with RMS amplitudes ≥0.060mag is given. From this list, 37 Cepheid candidates were selected after inspection of their light curves.
This catalog contains the results of a photometric survey for variable stars in a 9.4 square degree region along the galactic plane in Crux and Centaurus. A total of 300308 stars were observed at seven epochs over 42 days; 224 524 of these stars were detected at multiple epochs and were tested for possible variations in brightness that exceed observational error. 2422 stars are identified as variable at a formal confidence level of 99%; 270 of the new variables brighter than I=14.0 are classified as long period variables. A list of 242 likely short period variables with RMS amplitudes >=0.060mag is given. From this list, 37 Cepheid candidates were selected after inspection of their light curves.
