- ID:
- ivo://CDS.VizieR/J/A+A/420/571
- Title:
- V1974 Cyg IUE spectroscopy
- Short Name:
- J/A+A/420/571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a detailed analysis of the IUE archival high resolution spectra of the classical nova V1974 Cyg 1992. The main UV resonance lines show P Cygni profiles in the first days, which change into symmetric pure emission lines, and then slowly become fainter and narrower. Lines of higher ionization species reach their peak luminosity later than those of low ionization.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/551/A62
- Title:
- V2492 Cyg light variations
- Short Name:
- J/A+A/551/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- V2492 Cyg is a young eruptive star that went into outburst in 2010. The near-infrared color changes observed since the outburst peak suggest that the source belongs to a newly defined sub-class of young eruptive stars, where time-dependent accretion and variable line-of-sight extinction play a combined role in the flux changes. In order to learn about the origin of the light variations and to explore the circumstellar and interstellar environment of V2492 Cyg, we monitored the source at ten different wavelengths, between 0.55um and 2.2um from the ground and between 3.6um and 160um from space. We analyze the light curves and study the color-color diagrams via comparison with the standard reddening path. We examine the structure of the molecular cloud hosting V2492 Cyg by computing temperature and optical depth maps from the far-infrared data.
- ID:
- ivo://CDS.VizieR/J/PAZh/42/831
- Title:
- V1027 Cygni UBV and JHKLM photometry
- Short Name:
- J/PAZh/42/831
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our UBV and JHKLM photometry for the semiregular pulsating variable V1027 Cyg, a supergiant with an infrared excess, over the period from 1997 to 2015 (UBV) and in 2009-2015 (JHKLM). Together with the new data, we analyze the photometric observations of V1027 Cyg that we have obtained and published previously. Our search for a periodicity in the UBV brightness variations has led to several periods from P=212d to 320d in different time intervals. We have found the period P=237d based on our infrared photometry. The variability amplitude, the lightcurve shape, and the magnitude of V1027 Cyg at maximum light change noticeably from cycle to cycle.
- ID:
- ivo://CDS.VizieR/J/PAZh/41/148
- Title:
- V1329 Cyg UBV light curves and spectrum
- Short Name:
- J/PAZh/41/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photoelectric UBV observations of the peculiar symbiotic star V1329 Cyg performed at the Crimean Station of the SAI-MSU during 245 nights over the period 2003-2014 are presented. The star's light curves since 1973 from the Crimean observations are shown. The brightness decline after its outburst over the last 40 years was 0.8m-1.0m. The phase color curves at phases 0.2 and 0.8 have maxima. Their qualitative interpretation in terms of the model of interacting winds in symbiotic binary star systems is proposed. The orbital period of the binary system has been redetermined. The spectroscopic observations at the 125-cm telescope of the Crimean Station from 1994 to 2014 have confirmed the change in the system's emission spectrum with orbital phase.
- ID:
- ivo://CDS.VizieR/J/A+AS/139/513
- Title:
- 1975-1995 V1794 Cyg UBVRI photometry
- Short Name:
- J/A+AS/139/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Six years of new photometry of V 1794 Cyg is combined with the previously published data. These data are processed into two decades of homogeneous standard Johnson UBVRI photometry, which contains 1207, 1837, 1927, 867 and 75 observations in U, B, V, R and I, respectively.
- ID:
- ivo://CDS.VizieR/J/AN/336/70
- Title:
- Velocities and proper motions of Galactic Cepheids
- Short Name:
- J/AN/336/70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The kinematics and distribution of classical Cepheids within ~3 kpc from the Sun suggest the existence of the outer ring R1R2' in the Galaxy. The optimum value of the solar position angle with respect to the major axis of the bar, theta_b, providing the best agreement between the distribution of Cepheids and model particles is theta_b_=37+/-13{deg}. The kinematical features obtained for Cepheids with negative Galactocentric radial velocity V_R_ are consistent with the solar location near the descending segment of the outer ring R2. The sharp rise of extinction toward of the Galactic center can be explained by the presence of the outer ring R1 near the Sun.
- ID:
- ivo://CDS.VizieR/J/AJ/159/242
- Title:
- Velocities and transit times in the Kepler-88 system
- Short Name:
- J/AJ/159/242
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of Kepler-88d (P_d_=1403{+/-}14days, Msin_i_d__=965{+/-}44M_{Earth}_=3.04{+/-}0.13M_J_, e_d_=0.41{+/-}0.03) based on six years of radial velocity (RV) follow-up from the W.M.Keck Observatory High Resolution Echelle Spectrometer spectrograph. Kepler-88 has two previously identified planets. Kepler-88b (KOI-142.01) transits in the NASA Kepler photometry and has very large transit timing variations (TTVs). Nesvorny+, performed a dynamical analysis of the TTVs to uniquely identify the orbital period and mass of the perturbing planet (Kepler-88c), which was later was confirmed with RVs from the Observatoire de Haute-Provence (OHP). To fully explore the architecture of this system, we performed photodynamical modeling on the Kepler photometry combined with the RVs from Keck and OHP and stellar parameters from spectroscopy and Gaia. Planet d is not detectable in the photometry, and long-baseline RVs are needed to ascertain its presence. A photodynamical model simultaneously optimized to fit the RVs and Kepler photometry yields the most precise planet masses and orbital properties yet for b and c: P_b_=10.91647{+/-}0.00014days, M_b_=9.5{+/-}1.2M_{Earth}_, P_c_=22.2649{+/-}0.0007days, and M_c=214.0{+/-}5.3M_{Earth}_. The photodynamical solution also finds that planets b and c have low eccentricites and low mutual inclination, are apsidally anti-aligned, and have conjunctions on the same hemisphere of the star. Continued RV follow-up of systems with small planets will improve our understanding of the link between inner planetary system architectures and giant planets.
- ID:
- ivo://CDS.VizieR/J/A+A/412/447
- Title:
- Velocities of {lambda} Bootis stars
- Short Name:
- J/A+A/412/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We demonstrate that it is arduous to define the {lambda} Boo stars as a class of objects exhibiting uniform abundance peculiarities which would be generated by a mechanism altering the structure of their atmospheric layers. We collected the stars classified as {lambda} Boo up to now and discuss their properties, in particular the important percentage of confirmed binaries producing composite spectra (including our adaptive optics observations) and of misclassified objects. The unexplained RV variables (and thus suspected binaries), the known SB for which we lack information on the companion, the stars with an UV flux inconsistent with their classification, and the fast rotating stars for which no accurate abundance analysis can be performed, are also reviewed.
- ID:
- ivo://CDS.VizieR/J/ApJ/713/615
- Title:
- Very metal-poor Cepheid models
- Short Name:
- J/ApJ/713/615
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical Cepheids are primary distance indicators playing a fundamental role in the calibration of the extragalactic distance scale. The possible dependence of their characteristic period-luminosity (PL) relation on chemical composition is still debated in the literature, and the behavior of these pulsators at very low metallicity regimes is almost unexplored. In order to derive constraints on the application of the PL relation at low metal abundances, we investigate the properties of the few ultra-low metallicity (Z~0.0004) Cepheids recently discovered in the Blue Compact Dwarf galaxy IZw18. To this purpose, we have computed an updated and extended set of nonlinear convective models for Z=0.0004 and Y=0.24, spanning a wide range of stellar masses, and taking into account the evolutionary constraints for selected luminosity levels. As a result, we are able to predict the topology of the instability strip, the variations of all the relevant quantities along the pulsation cycle, including the morphology of the light curves, the theoretical period-luminosity-color, period-Wesenheit, and PL relations at such a low metallicity.
- ID:
- ivo://CDS.VizieR/J/AZh/92/323
- Title:
- V1239 Her light curves in quiescence
- Short Name:
- J/AZh/92/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a study of the integrated brightness of the SU UMa eclipsing binary V1239 Her are presented. The system was monitored on nine nights in 2013-2014 when the binary was in quiescence. The orbital period is refined (P_orb_=0.100082222(2)d) and the system's light curves obtained. These curves provide evidence for active processes in the system between outbursts: the depths of both minima and the amplitude of the pre-eclipse hump vary, and one of the light curves exhibits no hump at all. The parameters of the accretion disk, hot spot, and gas stream in V1239 Her for several epochs are determined in a "combined" model taking into account the contributions to the total radiation flux from the opaque part of the gas stream and the hot spot on the lateral surface of the disk.
