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2861. IC 4665 multi-band photometry
ID:
ivo://CDS.VizieR/J/A+A/641/A156
Title:
IC 4665 multi-band photometry
Short Name:
J/A+A/641/A156
Date:
21 Oct 2021
Publisher:
CDS
Description:
Debris discs orbiting young stars are key to understand dust evolution and the planetary formation process.We take advantage of a recent membership analysis of the 30Myr nearby open cluster IC 4665 based on the Gaia and DANCe surveys to revisit the disc population of this cluster. We aim to study the disc population of IC 4665 using Spitzer (MIPS and IRAC) and WISE photometry. We use several colour-colour diagrams with empirical photospheric sequences to detect the sources with an infrared excess. Independently, we also fit the spectral energy distribution (SED) of our debris disc candidates with the Virtual Observatory SED analyser (VOSA) which is capable of automatically detecting infrared excesses and provides effective temperature estimates. We find six candidates debris disc host-stars (five with MIPS and one with WISE) and two of them are new candidates. We estimate a disc fraction of 24+/-10% for the B-A stars, where our sample is expected to be complete. This is similar to what has been reported in other clusters of similar ages (Upper Centaurus Lupus, Lower Centaurus Crux, the $\beta$ Pictoris moving group, and the Pleiades). For solar type stars we find a disk fraction of 9+/-9%, lower than that observed in regions with comparable ages. Our candidates debris disc host-stars are excellent targets to be studied with ALMA or the future James Webb Space Telescope (JWST).
2862. Ic photometry of IC 348
ID:
ivo://CDS.VizieR/J/MNRAS/358/341
Title:
Ic photometry of IC 348
Short Name:
J/MNRAS/358/341
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a photometric study of I-band variability in the young cluster IC 348. The main purpose of the study was to identify periodic stars. In all, we find 50 periodic stars, of which 32 were previously unknown. For the first time in IC 348, we discover periods in significant numbers of lower-mass stars (M<0.25M_{sun}_) and classical T Tauri stars.
2863. IC 348 proper motion catalogue
ID:
ivo://CDS.VizieR/J/A+AS/137/305
Title:
IC 348 proper motion catalogue
Short Name:
J/A+AS/137/305
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new proper motion study for about 1400 stars with R<18mag in a one square degree region around the young open cluster IC 348 based on Schmidt plates is presented. With an overall accuracy of about 3mas/yr (2.5mas/yr, respectively for all stars with R<17mag) we have obtained membership probabilities dividing our sample into three groups: foreground stars, cluster stars and background stars. This separation is also supported by the proper motion distribution with respect to the direction of the standard antapex and an increase of mean proper motion cluster membership probabilities with smaller cluster radii. 240 stars of our sample have cluster membership probabilities larger than 80%.
2864. ICRF3 radio-loud quasars with Gaia DR2 data
ID:
ivo://CDS.VizieR/J/ApJ/873/132
Title:
ICRF3 radio-loud quasars with Gaia DR2 data
Short Name:
J/ApJ/873/132
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate a sample of 3413 International Celestial Reference Frame (ICRF3) extragalactic radio-loud sources with accurate positions determined by very long baseline interferometry in the S/X band, mostly active galactic nuclei and quasars, which are cross-matched with optical sources in the second Gaia data release (Gaia DR2). The main goal of this study is to determine a core sample of astrometric objects that define the mutual orientation of the two fundamental reference frames, the Gaia (optical) and the ICRF3 (radio) frames. The distribution of normalized offsets between the VLBI sources and their optical counterparts is non-Rayleigh, with a deficit around the modal value and a tail extending beyond the 3{sigma} confidence level. A few filters are applied to the sample in order to discard double cross-matches, confusion sources, and Gaia astrometric solutions of doubtful quality. Panoramic Survey Telescope and Rapid Response System and Dark Energy Survey stacked multicolor images are used to further deselect objects that are less suitable for precision astrometry, such as extended galaxies, double and multiple sources, and obvious misidentifications. After this cleaning, 2643 quasars remain, of which 20% still have normalized offset magnitudes exceeding 3, or a 99% confidence level. We publish a list of 2119 radio-loud quasars of prime astrometric quality. The observed dependence of binned median offset on redshift shows the expected decline at small redshifts, but also an unexpected rise at z~1.6, which may be attributed to the emergence of the CIV emission line in the Gaia's G band. The Gaia DR2 parallax zero-point is found to be color-dependent, suggesting an uncorrected instrumental calibration effect.
2865. IC 2714 UBV photometry
ID:
ivo://CDS.VizieR/J/A+AS/107/39
Title:
IC 2714 UBV photometry
Short Name:
J/A+AS/107/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
UBV photoelectric photometry for 204 stars in the field of the southern open cluster IC 2714 supplemented by DDO and Washington photometry and Coravel radial velocities of 14 probable red giants, are presented. The analysis of the photometric and kinematical data yielded 132 probable members and 13 possible members. IC 2714 contains one variable star and 11 red giant members, one of them being a spectroscopic binary. Two red giants are either binaries or non-members. The reddening across the cluster is slightly variable, the mean value is E(B-V)=0.36. The cluster distance-modulus is 11.68, corresponding to a distance of 1320(+/-120)pc and the mean radial velocity is -14.1+/-0.3km/s. The age, determined by fitting isochrones with core overshooting turned out to be log(t)=8.5, corresponding to 3.2 10^8 yr. A metal abundance [Fe/H]=-0.12+/-0.09 relative to the Sun and other fundamental parameters are determined. The luminosity function of the bright members of IC 2714 in good agreement with that determined by Taff (1974AJ.....79.1280T). For a description of the UBV, DDO and Washington photometric system, see e.g. <GCPD/01>, <GCPD/12> and <GCPD/45>
2866. IC 4651 uvby photometry
ID:
ivo://CDS.VizieR/J/A+A/361/929
Title:
IC 4651 uvby photometry
Short Name:
J/A+A/361/929
Date:
21 Oct 2021
Publisher:
CDS
Description:
New accurate CCD photometry in the u, v, b and y bands of the Stroemgren system filters has been obtained for 17640 stars to approximately. V=20mag in a approximately 21' x 21' field centered on the intermediate-age open cluster IC 4651. The observations was obtained with the Danish 1.5-m telescope at the European Southern Observatory, La Silla, Chile. Table 1 contains information about the Date, Night, Filter, Exposure time, Airmass, CCD rotation angle, and RA- , DE-offsets for all 89 frames. Table 2 gives cross-references between the MEI-system (this paper) and the Lindoff (1972A&AS....7..231L, IC 4651 NNN), Eggen (1971ApJ...166...87E, Cl* IC 4651 Egg NN), Anthony-Twarog & Twarog (1987AJ.....94.1222A, Cl* IC 4651 AT 1-NNN, Cl* IC 4651 AT 2-NN), and Anthony-Twarog et al. (1988AJ.....95.1453A, Cl* IC 4651 AMC I-NNN, Cl* IC 4651 AMC NNNN) identification numbers. Table 3 is the final catalogue of the new Stroemgren uvby photometry, ordered by MEI identification number. For each star, it gives the MEI number, Global CCD x- and y-coordinates, J2000 coordinates , the new y, b, v, and u magnitudes on the standard system, number of detections of the individual stars, and their mean errors.
2867. IC 4996 Vilnius phot. and Gaia DR2 astrometry
ID:
ivo://CDS.VizieR/J/A+A/623/A22
Title:
IC 4996 Vilnius phot. and Gaia DR2 astrometry
Short Name:
J/A+A/623/A22
Date:
21 Oct 2021
Publisher:
CDS
Description:
The open cluster IC 4996 in Cygnus and its vicinity are investigated applying two-dimensional photometric classification of stars measured in the Vilnius seven-color photometric system. Cluster members are identified by applying distances based on the Gaia DR2 parallaxes and the point vector diagram of the Gaia DR2 proper motions. For some B-type stars, spectroscopic MK types are also obtained from the Asiago spectra and collected from the literature. New parameters of the cluster are derived. Th interstellar extinction A(v) covers a wide range of values, from 1.3 to 2.4mag, the mean value in the central part of the cluster is 1.8mag. The cluster distance is 1915+/-110pc, and its age is within 8-10Myr. The cluster exhibits a long sequence from early B to G stars, where stars cooler than B8 are in the pre-main-sequence stage. The plot of the extinction versus distance shows a steep rise of A(v) up to 1.6mag at 700-800pc, which is probably related to dust clouds at the edge of the Great Cygnus Rift. The next extinction rise by an additional 0.8 mag at d>=1.7kpc is probably related to the associations Cyg OB1 and Cyg OB3. The cluster IC 4996 does not belong to the Cyg OB1 association, which is located closer to the Sun, at 1682+/-116pc. It seems likely that the cluster and the surrounding O-B stars have a common origin with the nearby association Cyg OB3 since the Gaia data show that these stellar groups are located at a similar distance.
2868. IC 361 Vilnius photometry
ID:
ivo://CDS.VizieR/J/BaltA/19/63
Title:
IC 361 Vilnius photometry
Short Name:
J/BaltA/19/63
Date:
21 Oct 2021
Publisher:
CDS
Description:
CCD photometry in the eight-color Vilnius + I system for 7250 stars down to I=19.6mag has been obtained in the 20'x26' field of the open cluster IC361 in Camelopardalis. The catalog of 1420 stars down to V~18.5mag is presented. It contains the coordinates, V magnitudes, seven color indices, quantitative photometric spectral types, absolute magnitudes and distances. The interstellar extinction is found to be non-uniform across the field, with the values of A_V_ in the range 1.9 to 2.4mag. The distribution of distance moduli of individual stars shows that the cluster is located as far as, or just beyond, the Perseus spiral arm.
2869. IC 1369 Vilnius photometry and Gaia DR2 astrometry
ID:
ivo://CDS.VizieR/J/AJ/159/95
Title:
IC 1369 Vilnius photometry and Gaia DR2 astrometry
Short Name:
J/AJ/159/95
Date:
21 Oct 2021
Publisher:
CDS
Description:
The open cluster IC1369, located in Cygnus close to the galactic equator at the 89.6{deg} longitude, and its vicinity are investigated by applying two-dimensional photometric classification of stars down to V=19mag measured in the Vilnius seven-color photometric system. Employing the Gaia DR2 coordinates, parallaxes, and proper motions, 143 cluster members are found having cluster membership probabilities >=0.75. The hottest stars of the evolved main sequence are of spectral class B9. Distances to the cluster, determined by two methods based on the Gaia parallaxes, are 3280 and 3370pc with an uncertainty of 400-500pc. Employing the physical HR diagram with the coordinates logL/L_{sun}_ versus logTeff and the Padova isochrones, the cluster age is found to be between 300 and 350Myr. Among the cluster members we identified six red giants of spectral classes G5-G8 and luminosities II-III, 17 Am stars, one Ap star, and one B5 blue straggler. The extinction shows a steep rise up to ~2.0mag at 300-700pc, caused by the extensions of the dust cloud LDN970 and the Great Cygnus Rift, and up to ~2.5mag at the edge of the Perseus arm at 3.0kpc. The extinction is almost constant between 0.9 and 2.5kpc from the Sun. The average extinction of the cluster members is 2.54mag. A systematic error of color excesses found in the Argonaut calculator results is discussed.
2870. IC 2602 VRI photometry
ID:
ivo://CDS.VizieR/J/A+AS/126/81
Title:
IC 2602 VRI photometry
Short Name:
J/A+AS/126/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of VRI photometry of the young open cluster IC 2602. Two 15x15arcmin^2^ fields were observed in February and May 1991 using the 1-m Swope telescope at Las Campanas. Using theoretical isochrones obtained from D'Antona & Mazzitelli (1994ApJS...90..467D), and allowing for observational and other uncertainties, we identify 78 primary candidate members with 12<V<18.5 from their positions on colour-magnitude diagrams. We compare the cluster field with an offset field of similar galactic latitude and estimate the contamination due to background stars to be large, >=50%, as might be expected given its low galactic latitude. We also compare our photometry with that given for the X-ray detected stars of Randich et al. (1995A&A...300..134R) present complimentary narrow band H{alpha} photometry for a subset of the stars.