- ID:
- ivo://CDS.VizieR/J/A+A/311/873
- Title:
- Geneva Photometry of HD 34798 & HD 45284
- Short Name:
- J/A+A/311/873
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the period analysis of two variable mid-B stars that have been observed in the Geneva photometric system between 1981 and 1990. Both HD 34798 and HD 45284 are multiperiodic g-mode pulsators that belong to the group of slowly pulsating B stars. The power spectrum of HD 34798 is characterized by several modes which have about equal power. This star belongs to a visual binary, the other component of which is a singly periodical CP star. Quasi-simultaneous observations of both stars are discussed and turn out to be helpful to illustrate the multiperiodic behavior of HD 34798. Three oscillation modes with a nearly stable amplitude are found; the remaining variability may be due to two very close oscillation modes, or, alternatively, to one mode with an intrinsically variable amplitude. Three oscillation frequencies can be distinguished clearly in the power spectrum of HD 45284. The beat periods for this star are the shortest for any SPB detected so far, and therefore make HD 45284 an excellent candidate for verification of our results and for asteroseimological follow-up.
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- ID:
- ivo://CDS.VizieR/J/A+A/341/469
- Title:
- Geneva photometry of NGC 2451 and HR 2968
- Short Name:
- J/A+A/341/469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The two clusters NGC 2451 A and B will be examined on the basis of Geneva multicolour photometric measurements. P and Q are the sum of the individual weights divided by 3 for the colours and the V magnitude respectively. For a description of the Geneva photometric system, see e.g. <GCPD/13>
- ID:
- ivo://CDS.VizieR/J/A+AS/132/367
- Title:
- Geneva photometry of the Algol system TZ Eri
- Short Name:
- J/A+AS/132/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Light curves of the semi-detached eclipsing binary system TZ Eridan in the Geneva 7-colour photometric system were analysed using the Wilson-Devinney programme. The physical and orbital parameters have been determined through a self-consistent simultaneous solution of the seven light curves and of the radial velocity curves of both components.
- ID:
- ivo://CDS.VizieR/J/A+A/454/855
- Title:
- Geneva photometry of W Cru
- Short Name:
- J/A+A/454/855
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Light curves of the long-period Algols are known for their complex (asymmetry in the eclipse, light variations outside the eclipse, changes from cycle-to-cycle), but their interpretation is not possible in the standard model of binary stars. We determined that complex structures present in these active Algol systems could be studied with the eclipse-mapping method that was successfully applied to the new 7-color photometric observations in the Geneva system of W Cru, belonging to the isolated group of these active Algols. Several cycles of this long-period (198.5-days) eclipsing binary were covered by observations. We used a modified Rutten's approach to the eclipse-mapping. The optimization of the system's parameters and the recovery of the disk intensity distribution are performed using a genetic algorithm (GA). The finding of a primary (hot) component is hidden in thick accretion disk confirms previous solutions. The mass of the primary component, M_1_=8.2M_{sun}_, indicates that it is a mid-B type star. The mass-losing component fills its critical lobe, which, for the system's parameters, means it is a G-type supergiant with a mass M_2_=1.6M_{sun}_. The disk is very extended geometrically, and its outer radius is about 80% of the primary's critical lobe. A reconstructed image reveals the rather clumpy and nonuniform brightness distribution of an accretion disk rim in this system that is seen almost edge-on. This clumpiness accounts for light curve distortions and asymmetries, as well as for secular changes.
- ID:
- ivo://CDS.VizieR/J/A+A/449/305
- Title:
- Geneva photometry time series of HD 203664
- Short Name:
- J/A+A/449/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made a seismic study of the young massive beta Cephei star HD 203664 with the goal of constraining its interior structure. Our study is based on a time series of 328 new Geneva 7-colour photometric data of the star spread over 496.8 days. The data confirm the frequency of the dominant mode of the star, which we refined to f_1_=6.02885c/d. The mode has a large amplitude of 37mmag in V and is unambiguously identified as a dipole mode (l=2) from its amplitude ratios and non-adiabatic computations. Besides f_1_, we discovered two additional new frequencies in the star with amplitudes above 4{sigma}: f_2_=6.82902c/d and f_3_=4.81543c/d, or one of their daily aliases. The amplitudes of these two modes are only between 3 and 4mmag, which explains why they were not detected before. Their amplitude ratios are too uncertain for mode identification. We show that the observed oscillation spectrum of HD 203664 is compatible with standard stellar models but that we have insufficient information for asteroseismic inferences. Among the large-amplitude beta Cephei stars, HD 203664 stands out as the only one rotating at a significant fraction of its critical rotation velocity (~40%).
- ID:
- ivo://CDS.VizieR/VI/102
- Title:
- Geneva stellar evolution tracks and isochrones
- Short Name:
- VI/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This database was created from an updated version of the empirically and semi-empirically calibrated BaSeL library of synthetic stellar spectra of Lejeune et al. (1997, Cat. <J/A+AS/125/229>, 1998, Cat. <J/A+AS/130/65>) and Westera et al. (1999, ASP Conference Series 192, 203-206) to calculate synthetic photometry in the (UBV)_J_(RI)_C_ JHKLL'M, HST-WFPC2, Geneva, and Washington systems for the entire set of non-rotating Geneva stellar evolution models covering masses from 0.4-0.8 to 120-150M_{sun}_ and metallicities Z=0.0004 (1/50Z_{sun}_) to 0.1 (5Z_{sun}_). The results are provided in a database which includes all individual stellar tracks and the corresponding isochrones covering ages from 10^3^yr to 16-20Gyr in time steps of {Delta}logt=0.05dex. The database also includes a new grid of stellar tracks of very metal-poor stars (Z=0.0004) from 0.8-150M_{sun}_ calculated with the Geneva stellar evolution code. The complete stellar grids are tabulated in the files table1.dat (summary), evol.dat (evolutionary models), and in the files ubv.dat, hst.dat, gen.dat and cmt.dat (synthetic colors in the different photometric systems). These grids are also available as mod* files in subdirectories evol, ubv, hst, gen and cmt. The isochrones for the different photometric systems are summarized in the file table2.dat; the parameters of the isochrones are tabulated in the file iso.dat, the detailed isochrones being available as files iso* in the subdirectories ubv, hst, gen and cmt.
- ID:
- ivo://CDS.VizieR/J/PASP/109/883
- Title:
- Globular metallicity scale. I.
- Short Name:
- J/PASP/109/883
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained 2640 CCD spectra with resolution ~4{AA} in the region 7250-9000{AA} for 976 stars lying near the red giant branches in color-magnitude diagrams of 52 Galactic globular clusters. Radial velocities of ~16km/s accuracy per star determined from the spectra are combined with other criteria to assess quantitative membership probabilities. Measurements of the equivalent widths of the infrared calcium triplet lines yield a relative metal-abundance ranking with a precision that compares favorably to other techniques. Regressions between our system and those of others are derived. Our reduction procedures are discussed in detail, and the resultant catalog of derived velocities and equivalent widths is presented. The metal abundances derived from these data will be the subject of a future paper. (c) Astronomical Society of the Pacific
- ID:
- ivo://CDS.VizieR/J/AJ/160/277
- Title:
- gri-light curve of near-Earth asteroid 2020 CD3
- Short Name:
- J/AJ/160/277
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We report on our detailed characterization of Earth's second known temporary natural satellite, or minimoon, asteroid 2020CD3. An artificial origin can be ruled out based on its area-to-mass ratio and broadband photometry, which suggest that it is a silicate asteroid belonging to the S or V complex in asteroid taxonomy. The discovery of 2020CD3 allows for the first time a comparison between known minimoons and theoretical models of their expected physical and dynamical properties. The estimated diameter of 1.2_-0.2_^+0.4^m and geocentric capture approximately a decade after the first known minimoon, 2006RH120, are in agreement with theoretical predictions. The capture duration of 2020CD3 of at least 2.7yr is unexpectedly long compared to the simulation average, but it is in agreement with simulated minimoons that have close lunar encounters, providing additional support for the orbital models. 2020CD3's atypical rotation period, significantly longer than theoretical predictions, suggests that our understanding of meter-scale asteroids needs revision. More discoveries and a detailed characterization of the population can be expected with the forthcoming Vera C. Rubin Observatory Legacy Survey of Space and Time.
- ID:
- ivo://CDS.VizieR/J/ApJ/702/1353
- Title:
- H{beta} and V-band light curves of NGC 4051
- Short Name:
- J/ApJ/702/1353
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved H{beta} reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ~2-3{sigma} outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity - the R_BLR_-L relationship. Our new measurements of the lag time between variations in the continuum and H{beta} emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R_BLR_=1.87^+0.54^_-0.50_ light days and black hole mass of M_BH_=(1.73^+0.55^_-0.52_)x10^6^M_{sun}_. We also present a preliminary look at velocity-resolved H{beta} light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.
- ID:
- ivo://CDS.VizieR/J/A+A/347/164
- Title:
- HD 59435 Geneva photometry
- Short Name:
- J/A+A/347/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SB2 binary HD 59435 hosts a yellow giant and a magnetic Ap star, the latter being the secondary (Wade et al., 1996, Cat. <J/A+A/314/491>) and exhibiting spectral lines resolved into their magnetically-split components. Additional measurements of the magnetic field modulus of the Ap secondary are reported, as well as additional radial velocities for both components and photometric magnitudes and colours in the Geneva system. The magnetic field modulus varies with a period of about 1360 days. For a general description of the Geneva photometric system, see e.g. <GCPD/13>
