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- ID:
- ivo://CDS.VizieR/J/A+A/590/A116
- Title:
- Nainital-Cape Survey. IV.
- Short Name:
- J/A+A/590/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Nainital-Cape Survey is a dedicated ongoing Survey programme to search for and study pulsational variability in chemically peculiar (CP) stars to understand their internal structure and evolution. The main aims of this Survey are to find new pulsating Ap and Am stars in the northern and southern hemisphere and to perform asteroseismic studies of these new pulsators. The Survey is conducted using high-speed photometry. The candidate stars were selected on the basis of having Stromgren photometric indices similar to those of known pulsating CP stars. Over the last decade a total of 337 candidate pulsating CP stars were observed for the Nainital-Cape Survey, making it one of the longest ground-based surveys for pulsation in CP stars in terms of time span and sample size. The previous papers of this series presented seven new pulsating variables and 229 null results. In this paper we present the light curves, frequency spectra and various astrophysical parameters of the 108 additional CP stars observed since the last reported results. We also tabulated the basic physical parameters of the known roAp stars. As a part of establishing the detection limits in the Nainital-Cape Survey, we investigated the scintillation noise level at the two observing sites used in this Survey, Sutherland and Nainital, by comparing the combined frequency spectra stars observed from each location. Our analysis shows that both the sites permit the detection of variations of the order of 0.6-milli-magnitude (mmag) in the frequency range 1-4mHz, Sutherland is on average marginally better.
- ID:
- ivo://CDS.VizieR/II/195B
- Title:
- Namelists of variable stars Nos.67-73
- Short Name:
- II/195B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a computer-readable version of six Name-Lists of Variable Stars (Nos.67-72) published in the system introduced during the preparation of the 4th GCVS edition. For printed versions of these Name-Lists see IBVS No.2681,1985; No.3058,1987; No.3323,1989; No.3530,1990; No.3840,1993; No.4140,1995. The main body of the 4th GCVS edition is already available in computer-readable form (see <II/139>, <II/172>, <II/205>). There are 2735 stars in the Name-Lists Nos.67-72 (file "nl.dat"). The variables are arranged in the order of their names inside constellations. One star of the 67th Name-List (V1810 Cyg=No.67247) turned out to be non-existing, it has been excluded from the table. The identification table (file "ident.dat") and the list of references (file "ref.dat") follow. The total number of designated variable stars has now reached 31193. In the new computer-readable version 1.1 of the GCVS, vol. IV (catalog <II/172>), we now present identifications also for name-list stars. We make no special attempt to present the material in a completely homogeneous form. There happened minor style evolution from the 67th to the 70th Name-List: particularly, the 67th Name-List normally refers in the identification table only to the catalogues cited in the papers mentioned in the references in the files "nl.dat" and "ident.dat", and to the 70th Name-List it became a common practice to give more catalogue identifications. From the Name-List No.70, there is no completeness in identifications with the old catalogues of suspected variables (CSV), in many cases we consider the NSV identification sufficient. We also do not try to update the information of the older Name-Lists, we only put the information together and correct known mistakes. The corrections to the Name-Lists have been taken into account. It is necessary to reproduce here two remarks from forewords of the printed Name-Lists: Name-List No.69. In the case of the variable stars in the open cluster NGC 3766 (V843-V849 Cen), there is some ambiguity in their identification with the HD,CoD,CPD catalogues. In particular, we do not agree with the HD catalogue identification of HD 100856 with CPD-60 3102 and consider V843 Cen=CPD-60 3102 to be identical with HDE 306794; HD 100856=CPD-60 3112. Name-List No.70. The 70th Name-List contains a number of variables in Taurus discovered by J. Kelemen [70113]. Unfortunately the discovery announcement contains some mistakes in co-ordinates and in identifications with other lists. These mistakes have been corrected according to [70114]. (Added in version II/195B) The name-list number 73 was added at CDS on 26-Sep-1997. It was kept in a different file because it is differently formatted (better accuracy in the position). The references of this 73rd name list were however merged with the previous ones in the file ref.dat.
- ID:
- ivo://CDS.VizieR/J/A+A/466/1099
- Title:
- N-band visibilities of V Oph
- Short Name:
- J/A+A/466/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first multi-epoch N-band spectro-interferometric observations of the carbon-rich Mira variable V Oph using MIDI at the ESO's Very Large Telescope Interferometer. Our aim is to study temporal variations of physical properties of the outer atmosphere and the circumstellar dust shell based on spectrally-dispersed N-band visibilities over the C_2_H_2_ (+HCN) features and the dust emission.
- ID:
- ivo://CDS.VizieR/J/AJ/156/112
- Title:
- Near-infrared Mira period-luminosity relations in M33
- Short Name:
- J/AJ/156/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze sparsely sampled near-infrared (JHK_s_) light curves of a sample of 1781 Mira variable candidates in M33, originally discovered using I-band time-series observations. We extend our single-band semi-parametric Gaussian process modeling of Mira light curves to a multiband version and obtain improved period determinations. We use our previous results on near-infrared properties of candidate Miras in the LMC to classify the majority of the M33 sample into oxygen- or carbon-rich subsets. We derive period-luminosity relations for O-rich Miras and determine a distance modulus for M33 of 24.80+/-0.06 mag.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A14
- Title:
- Near-infrared photometry of {eta} Carinae
- Short Name:
- J/A+A/564/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eta Car's ultra-violet, optical, and X-ray light curves and its spectrum suggest a physical change in its stellar wind over the last decade. It has been proposed that the mass-loss rate has decreased by a factor of about 2 over the last 15 years. We complement these recent results by investigating the past evolution and the current state of eta Car in the near-infrared (IR).
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/1709
- Title:
- Near-infrared survey of Miras
- Short Name:
- J/MNRAS/399/1709
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a near-infrared survey for long-period variables in a field of view of 20x30arcmin^2^ towards the Galactic Centre (GC). We have detected 1364 variables, of which 348 are identified with those reported in Glass et al. (2001. Cat. <J/MNRAS/321/77>). We present a catalogue and photometric measurements for the detected variables and discuss their nature.
- ID:
- ivo://CDS.VizieR/J/A+A/553/A48
- Title:
- Near-infrared variability in RCW 38
- Short Name:
- J/A+A/553/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We want to study the content of young stellar objects in the RCW 38 cluster by means of multi-epoch variability studies. We performed a three-month near-infrared (NIR) monitoring campaign of the young cluster RCW 38 using the 80cm IRIS telescope near Cerro Armazones, Chile. Variability data with a median sampling of 1 day was gathered for 1026 sources, while a total of 3433 sources in JHK could be studied in the co-added, deep images with a completeness limit of K<15mag.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A123
- Title:
- Near-IR imaging polarimetry of HD142527
- Short Name:
- J/A+A/556/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HD 142527 is a pre-transition disk with strong evidence for ongoing planet formation. Recent observations show a disrupted disk with spiral arms, a dust-depleted inner cavity and the possible presence of gas streams driving gas from the outer disk toward the central star. We aim to derive the morphology of the disk, and the distribution and properties of the dust at its surface. We have obtained polarized differential images of HD 142527 at H and Ks bands with NaCo at the VLT. Combining these images with classical PSF-subtraction, we are able to derive the polarization degree of this disk. Results. At H band the polarization degree of the disk varies between 10% and 25%. This result cannot be reproduced by dust distributions containing highly porous material. The polarization is better matched by distributions of compact particles, with maximum sizes at least up to a few microns, in agreement with previous observations. We also observe two regions of low emission (nulls) in total and in polarized intensity. In particular, one of these nulls is at roughly the same position as the maximum of the horse-shoe shape observed in sub- millimeter continuum emission ALMA band-7 (345GHz) observations. We discuss the possible link between these two features.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A125
- Title:
- Neutron-capture elements abundances in Cepheids
- Short Name:
- J/A+A/586/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R~38000) and high signal-to-noise ratio (S/N~50-300) spectra collected with UVES at ESO VLT for the DIONYSOS project. Taking account for similar Cepheid abundances provided either by our group (111 stars) or available in the literature, we end up with a sample of 435 Cepheids covering a broad range in iron abundances (-1.6<[Fe/H]<0.6). We found, using homogeneous individual distances and abundance scales, well defined gradients for the above elements. However, the slope of the light s-process element (Y) is at least a factor of two steeper than the slopes of heavy s- (La, Ce, Nd) and r- (Eu) process elements. The s to r abundance ratio ([La/Eu]) of Cepheids shows a well defined anticorrelation with of both Eu and Fe. On the other hand, Galactic field stars attain an almost constant value and only when they approach solar iron abundance display a mild enhancement in La. The [Y/Eu] ratio shows a mild evidence of a correlation with Eu and, in particular, with iron abundance for field Galactic stars. We also investigated the s-process index -- [hs/ls] -- and we found a well defined anticorrelation, as expected, between [La/Y] and iron abundance. Moreover, we found a strong correlation between [La/Y] and [La/Fe] and, in particular, a clear separation between Galactic and Sagittarius red giants. Finally, the comparison between predictions for low-mass asymptotic giant branch stars and the observed [La/Y] ratio indicate a very good agreement over the entire metallicity range covered by Cepheids. However, the observed spread, at fixed iron content, is larger than predicted by current models.
