- ID:
- ivo://CDS.VizieR/J/MNRAS/428/502
- Title:
- UBVI photometry of 7 open clusters
- Short Name:
- J/MNRAS/428/502
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New photometric material is presented for six outer disc supposedly old, Galactic star clusters: Berkeley 76, Haffner 4, Ruprecht 10, Haffner 7, Haffner 11 and Haffner 15, which are projected against the rich and complex Canis Major overdensity at 225{deg}<=l<=248{deg}, -7{deg}b<=-2{deg}. This CCD data set, in the UBVI passbands, is used to derive their fundamental parameters, in particular age and distance. Four of the program clusters turn out to be older than 1Gyr. This fact makes them ideal targets for future spectroscopic campaigns aiming at deriving their metal abundances. This, in turn, contributes to increase the number of well-studied outer disc old open clusters. Only Haffner 15, previously considered an old cluster, is found to be a young, significantly reddened cluster, member of the Perseus arm in the third Galactic quadrant. As for Haffner 4, we suggest an age of about half a Gyr. The most interesting result we found is that Berkeley 76 is probably located at more than 17kpc from the Galactic centre, and therefore is among the most peripherical old open clusters so far detected. Besides, for Ruprecht 10 and Haffner 7, which were never studied before, we propose ages larger than 1Gyr. All the old clusters of this sample are scarcely populated and show evidence of tidal interaction with the Milky Way, and are therefore most probably in advanced stages of dynamical dissolution.
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- ID:
- ivo://CDS.VizieR/J/A+A/536/A101
- Title:
- UBVI photometry towards (l=314,b=0)
- Short Name:
- J/A+A/536/A101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spiral structure of the Milky Way is nowadays receiving renewed attention thanks to the combined efforts of observational campaigns in different wavelength regimes, from the optical to the radio. We start in the paper the exploration of a number of key sectors (line of sights) in the inner Milky Way, where the spiral structure is still poorly known. We search for density enhancements of young stars that might plausibly be associated with spiral structure. To this aim we collect sufficiently wide-field UBVI photometry to allow us to probe in statistical sense the distribution in reddening and distance of young stars in the field. The intensive usage of U-band photometry - although heavily demanding in terms of observational efforts - ensures robust determination of reddening and hence distance for stars of spectral type earlier than A0, which are well-known spiral arm tracers, even though no spectroscopic information are available. The fields we use are large enough to include in most cases well-studied Galactic clusters, which we use as bench-marks to assess the quality and standardisation of the data, and to validate our method. We focus in this paper on the line of sight to the Galactic longitude l=314{deg}, where previous surveys already detected H{alpha} emitters at different standard of rest velocities, and hence distances. The difficulty, however, to translate velocity into distance make predictions on the spiral structure quite vague. First of all, we made exhaustive tests to show that our data-set is in the standard system, and calibrated our method using the two open clusters NGC 5617 and Pismis 19 which happen to be in the field, and for which we found estimates of the basic parameters in full agreement with the literature. We then applied the method to the general field stars and detected signatures of three different groups of stars, evenly distributed across the field of view, at 1.5^+0.5^_-0.2_, 2.5^+0.3^_-0.5_, and 5.1^+1.5^_-1.1_kpc, respectively. These distances are compatible with the location of the nowadays commonly accepted description of the Carina-Sagittarius and Scutum-Crux arms, at heliocentric distance of ~2 an 5kpc, respectively. As a consequence, we consider these groups to be good candidates to trace the location of these two inner arms. In line with previous studies, this investigation demonstrates once again how powerful the use of U-band photometry is to characterize ensembles of young stars, and make predictions on the spiral structure of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/AZh/71/618
- Title:
- UBVJHKLM Photometry of Nova Cygni 1992
- Short Name:
- J/AZh/71/618
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of photometric UBVJHKLM observations of Nova Cygni 1992 performed from the 83d until the 290th day after the nova outburst are presented. The accuracy of the brightness estimate was better than 0.03mag for UBVJHK, 0.05mag for L, and 0.1mag for M bands.
- ID:
- ivo://CDS.VizieR/J/A+A/394/617
- Title:
- UBVJHKLM photometry of R Corona Borealis
- Short Name:
- J/A+A/394/617
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of UBVJHKLM photometry of R CrB spanning the period from 1976 to 2001.
- ID:
- ivo://CDS.VizieR/J/A+A/457/637
- Title:
- UBVJHK synthetic photometry of Galactic O stars
- Short Name:
- J/A+A/457/637
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The development of powerful infrared observational techniques enables the study of very extincted objects and young embedded star-forming regions. This is especially interesting in the context of massive stars that form and spend a non negligible fraction of their life still enshrouded in their parental molecular cloud. Spectrophotometric calibrations are thus necessary to constrain the physical properties of heavily extincted objects.
- ID:
- ivo://CDS.VizieR/J/A+A/373/950
- Title:
- UBV light cures of KW Persei
- Short Name:
- J/A+A/373/950
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table 4 summarizes the photoelectric UBV magnitudes of the eclipsing binary KW Per. This observational material was taken at the Observatories of the Astronomical Institute of the Slovak Academy of Sciences at the Stara Lesna (SL) and Skalnate Pleso (SP), as well as at the Astronomical Station of the National Observatory of Athens at Kryonerion (KR). The observations were carried out in 25 runs (24 nights) during the period from December 4th 1996 to November 25th 1998 in 112 hours of pure observational time. At the observatories SL and SP identical Cassegrain telescopes with a diameter of 60 cm were used. The observations of KR were performed by the same type of telescope with diameter of the primary mirror 120 cm. An one-channel photoelectric photometer with digital converter was used, as well as standard UBV Johnson's filters. All observational data, collected in table 4 are in the form of phase and magnitude for U, B and V colours. For determination of the phase, a newly derived ephemeris was used (this paper): MinI = HJD 2451143.27313 + 0.93125953 x E
- ID:
- ivo://CDS.VizieR/J/PAZh/32/737
- Title:
- UBV light curve and spectroscopy of StHa62
- Short Name:
- J/PAZh/32/737
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric observations of HD 51585 (OY Gem), a B[e] star with an infrared excess and a candidate for protoplanetary nebulae, obtained with a 60-cm telescope at the Crimean Station of Sternberg Astronomical Institute in 1992-2005 are presented. The star exhibited rapid irregular brightness variations with amplitudes from 0.1mag in the V band to 0.2mag in the U band within the observing season as well as slow systematic variations. with a quasi-period of ~2800-days. Low-resolution spectroscopy performed in 1994-2005 has revealed significant variability of the Balmer and Paschen hydrogen emission lines as well as the HeI and OI lines. Equivalent widths are given for the HI, HeI, OI, and FeII lines. Correlation has been found between the star's photometric variability and the hydrogen line intensities.
- ID:
- ivo://CDS.VizieR/J/AZh/80/535
- Title:
- UBV light curves of BE UMa
- Short Name:
- J/AZh/80/535
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBV photoelectric observations of BE Ursae Majoris, precataclysmic eclipsing variable with a strong reflection effect.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/131
- Title:
- UBV light curves of DQ Tau and UZ Tau E
- Short Name:
- J/ApJ/811/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The transfer of matter between a circumbinary disk and a young binary system remains poorly understood, obscuring the interpretation of accretion indicators. To explore the behavior of these indicators in multiple systems, we have performed the first systematic time-domain study of young binaries in the ultraviolet. We obtained far- and near-ultraviolet HST/COS spectra of the young spectroscopic binaries DQ Tau and UZ Tau E. Here we focus on the continuum from 2800 to 3200{AA} and on the CIV doublet ({lambda}{lambda}1548.19,1550.77{AA}) as accretion diagnostics. Each system was observed over three or four consecutive binary orbits, at phases ~0, 0.2, 0.5, and 0.7. Those observations are complemented by ground-based U-band measurements. Contrary to model predictions, we do not detect any clear correlation between accretion luminosity and phase. Further, we do not detect any correlation between CIV flux and phase. For both stars the appearance of the CIV line is similar to that of single Classical T Tauri Stars (CTTSs), despite the lack of stable long-lived circumstellar disks. However, unlike the case in single CTTSs, the narrow and broad components of the CIV lines are uncorrelated, and we argue that the narrow component is powered by processes other than accretion, such as flares in the stellar magnetospheres and/or enhanced activity in the upper atmosphere. We find that both stars contribute equally to the narrow component CIV flux in DQ Tau, but the primary dominates the narrow component CIV emission in UZ Tau E. The CIV broad component flux is correlated with other accretion indicators, suggesting an accretion origin. However, the line is blueshifted, which is inconsistent with its origin in an infall flow close to the star. It is possible that the complicated geometry of the region, as well as turbulence in the shock region, are responsible for the blueshifted line profiles.
- ID:
- ivo://CDS.VizieR/J/PAZh/30/855
- Title:
- UBV light curves of IRAS 19200+3457
- Short Name:
- J/PAZh/30/855
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of UBV photometric and spectroscopic observations of the early B supergiant with an IR excess IRAS 19200+3457.
