- ID:
- ivo://CDS.VizieR/J/AJ/149/146
- Title:
- UBV(RI)c differential light curves of HR Boo
- Short Name:
- J/AJ/149/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HR Bootis is a neglected binary that is found to be a solar-type (G2V) extreme mass ratio binary (EMRB). It was discovered by Hanley & Shapley in 1940. Surprisingly, little has been published in the intervening years. In 1999 it was characterized by a 0.31587day orbital period. Since that time it has been observed by various observers who have determined ~20 timings of minimum light over the past ~15000 orbits. Our observations in 2012 represent the first precision curves in the BVR_c_I_c_Johnson-Cousins wavelength bands. The light curves have rather low amplitudes, averaging some 0.5 magnitudes, yet they exhibit total eclipses, which is typical of the rare group of solar-type EMRBs. An improved linear ephemeris was computed along with a quadratic ephemeris showing a decaying orbit, which indicates magnetic breaking may be occurring. The light curve solution reveals that HR Boo is a contact system with a somewhat low 21% Roche-lobe fill-out but a mass ratio of q=4.09 (0.2444), which defines it as an EMRB. Two spots, both hot, were allowed to iterate to fit the light curve asymmetries. Their radii are 32{deg} and 16{deg}. Both are high-latitude polar spots indicative of strong magnetic activity. The shallow contact yet nearly equal component temperatures makes it an unusual addition to this group.
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- ID:
- ivo://CDS.VizieR/J/A+A/493/959
- Title:
- UBV(RI)cHalpha photometry in omega Cen
- Short Name:
- J/A+A/493/959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- omega Centauri is the most well studied Galactic Globular Cluster because of its numerous puzzling features: significant dispersion in metallicity, multiple populations, triple main-sequence, horizontal branch morphology, He-rich population(s), and extended star-formation history. Intensive spectroscopic follow-up observing campaigns targeting stars at different positions in the color-magnitude diagram promises to clarify some of these peculiarities. To be able to target cluster members reliably during spectroscopic surveys and both spatial and radial distributions in the cluster outskirts without including field stars, a high quality proper-motion catalog of omega Cen and membership probability determination are required. The only available wide field proper-motion catalog of omega Cen is derived from photographic plates, and only for stars brighter than B~16. Using ESO archive data, we create a new, CCD-based, proper-motion catalog for this cluster, extending to B~20. We used high precision astrometric software developed specifically for data acquired by WFI@2.2m telescope and presented in the first paper of this series.
- ID:
- ivo://CDS.VizieR/J/A+A/320/185
- Title:
- UBVRIcJHKL photometry in Lup
- Short Name:
- J/A+A/320/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a recent study, some 130 new weak-line T Tauri stars (WTTS) have been discovered in the Lupus star forming region (SFR). Some of these stars are seen projected onto regions of high obscuration, while others are located far from the Lupus dark clouds. In this paper we present photometric observations of a large sample of these WTTS. We estimate effective temperatures and luminosities for the stars observed, and derive masses and ages by comparison with theoretical evolutionary tracks. The photometric observations were performed at the ESO 1 m-Telescope during two observing runs in 1993 (March 10-12) and 1994 (May 1-6) at ESO, La Silla. The typical standard deviations are 0.01mag in V, 0.02mag in B-V, 0.04mag in U-B, 0.01 in V-R and V-I. For a description of the UBV, (RI)c and JHKL photometric systems, see e.g. <GCPD/01>, <GCPD/54> and <GCPD/09>
- ID:
- ivo://CDS.VizieR/J/MNRAS/367/1441
- Title:
- UBV(RI)cJHK photometry of NGC 2401
- Short Name:
- J/MNRAS/367/1441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on a deep optical CCD (UBV(RI)_C) photometric survey and on the Two-Micron All-Sky-Survey (2MASS, <II/246>) data we derived the main parameters of the open cluster NGC 2401. We found this cluster is placed at 6.3+/-0.5kpc (Vo-Mv=14.0+/-0.2) from the Sun and is 25Myr old, what allows us to identify NGC 2401 as a member of the young population belonging to the innermost side of the extension of the Norma-Cygnus spiral-arm in the Third Galactic Quadrant. A spectroscopic study of the emission star LSS 440 that lies in the cluster area revealed it is a B0Ve star; however, we could not confirm it is a cluster member. We also constructed the cluster luminosity function (LF) down to V~22 and the cluster initial mass function (IMF) for all stars with masses above M~1-2M_{sun}_. It was found that the slope of the cluster IMF is x~1.8+/-0.2. The presence of a probable PMS star population associated to the cluster is weakly revealed.
- ID:
- ivo://CDS.VizieR/J/AZh/87/462
- Title:
- UBV(RI)c light curves of BD+66 1663
- Short Name:
- J/AZh/87/462
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained the first UBV(RI)C photoelectric light curves of the recently discovered eclipsing binary BD+66 1663 = GSC 4479 412 (P=7.04d, V=10.14). We have derived relative and absolute parameters of the binary, and analyzed the interstellar extinction towards the object. Though the star is located in the field of the young open cluster Be 59, we demonstrate that it is not a member.
- ID:
- ivo://CDS.VizieR/J/A+A/492/145
- Title:
- UBV(RI)c light curves of Nova Cygni 2006
- Short Name:
- J/A+A/492/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nova Cyg 2006 has been intensively observed throughout its full outburst. We investigate the energetics and evolution of the central source and of the expanding ejecta, their chemical abundances and ionization structure, and the formation of dust. We recorded low, medium, and/or high-resolution spectra (calibrated into accurate absolute fluxes) on 39 nights, along with 2353 photometric UBVRcIc measures on 313 nights, and complemented them with IR data from the literature. The nova displayed initially the normal photometric and spectroscopic evolution of a fast nova of the FeII-type. Pre-maximum, principal, diffuse-enhanced, and Orion absorption systems developed in a normal way. After the initial outburst, the nova progressively slowed its fading pace until the decline reversed and a second maximum was reached (eight months later), accompanied by large spectroscopic changes. Following the rapid decline from second maximum, the nova finally entered the nebular phase and formed optically thin dust. We performed a photo-ionization analysis of the emission-line spectrum during the nebular phase, which showed a strong enrichment of the ejecta in nitrogen and oxygen, and none in neon, in agreement with theoretical predictions for the estimated 1.0M_{sun}_ white dwarf in Nova Cyg 2006. The similarities with the poorly investigated V1493 Nova Aql 1999a are discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/296
- Title:
- UBV(RI)c phot. of omega Cen (NGC5139) subgiants
- Short Name:
- J/ApJ/663/296
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine spectroscopic and photometric data for subgiant stars of {omega} Cen to extract results that neither data set could have provided on its own. GIRAFFE@VLT spectra of 80 stars at R=6400 give metallicities for all of them and abundances of C, N, Ca, Ti, and Ba for a subset of them. The photometric data, which have unusually high accuracy, come from a ~10x10arcmin^2^ mosaic of HST ACS images centered on the cluster center and on multicolor images of a ~34x33arcmin^2^ field, taken with the WFI@ESO2.2m camera. Stars with [Fe/H]<-1.25 have a large magnitude spread on the flat part of the sub-giant branch (SGB). We interpret this as empirical evidence for an age spread, and from theoretical isochrones we derive a relative age for each star.
- ID:
- ivo://CDS.VizieR/J/MNRAS/337/133
- Title:
- UBV(RI)c photometry in clusters Tr 1 and Be 11
- Short Name:
- J/MNRAS/337/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep UBV(RI)C charge-coupled device (CCD) photometry for the young open star clusters Tr 1 and Be 11. The CCD data for Be 11 are obtained for the first time. The sample consists of ~1500 stars reaching down to V~21mag. Analysis of the radial distribution of the stellar surface density indicates that radius values for Tr 1 and Be 11 are 2.3 and 1.5pc, respectively. The interstellar extinction across the face of the imaged clusters region seems to be non-uniform with a mean value of E(B-V)=0.60+/-0.05 and 0.95+/-0.05mag for Tr 1 and Be 11, respectively. A random positional variation of E(B-V) is present in both the clusters. In the cluster Be 11, the reason for the random positional variation may be the apparent association of the H II region (S 213). The 2MASS JHK data in combination with the optical data in the cluster Be 11 yield E(J-K)=0.40+/-0.20mag and E(V-K)=2.20+/-0.20mag. Colour excess diagrams indicate a normal interstellar extinction law in the direction of the cluster Be 11.
- ID:
- ivo://CDS.VizieR/J/A+A/432/657
- Title:
- UBV(RI)c photometry of AB Dor
- Short Name:
- J/A+A/432/657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse photometric observations of the young active dwarf AB Dor, spanning more than 20 years, and including previously unpublished data. The data in table2.dat was observed at Molehill Astronomical Observatory (Auckland, New Zealand) by M. Bos using a 200mm f10 Schmidt-Cassegrain Telescope with standard Johnson B and V filters. The data in table3.dat was observed by G. Cutispoto using the 0.5m telescope at the European Southern Observatory (ESO, La Silla, Chile) and the 0.5~m SAAO telescope (Sutherland, South Africa) with UBV(RI)c filters.
- ID:
- ivo://CDS.VizieR/J/A+AS/119/281
- Title:
- UBV(RI)c photometry of active stars.
- Short Name:
- J/A+AS/119/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-precision UBV(RI)_c_ photometry of 12 selected active stars, collected at the European Southern Observatory (La Silla, Chile) over the period February-March 1990, is presented. Significant evolution of the light curves, period variations and, in most cases, evidence for long-term variability of the global degree of spottedness are found. Some of the spectral classifications are discussed. This paper is part of a more extensive program focusing on the global properties and evolution of active stars and is aimed at establishing a time-extended photometric database which can give important clues on topics such as the stability of the spotted areas, differential rotation and solar-like cycles. For a description of the UBV and (RI)c photometric systems, see e.g. General Catalog of Photometric Data <GCPD/01> and <GCPD/54>.
