- 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.
Number of results to display per page
Search Results
- 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.
817. 6 new Beta Cep stars
- ID:
- ivo://CDS.VizieR/J/A+A/361/245
- Title:
- 6 new Beta Cep stars
- Short Name:
- J/A+A/361/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ground-based follow-up photometry in the Geneva seven-colour photometric system of six new {beta} Cep stars. The variability of these objects was originally found from the HIPPARCOS mission. The new data provided here allowed us to confirm their {beta} Cep-type nature, to detect the pulsational frequencies and to identify the degrees of the pulsation modes. For definitions of the Geneva photometric system, see <GCPD/13>.
- ID:
- ivo://CDS.VizieR/J/AcA/60/261
- Title:
- New bright periodic variables toward Galactic Bulge
- Short Name:
- J/AcA/60/261
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on photometric I-band observations of 147 bright (8<I<13) periodic variable stars toward the Galactic bulge including 76 new discoveries. We used one of the HATnet telescopes to obtain 151 exposures spanning 88 nights in 2005 of an 8.4{deg}x8.4{deg} field of view (FOV) approximately centered on (l,b)=(1.73,-4.68). We observed the Galactic bulge in 2005 as part of a microlensing feasibility study, and here we discuss the periodic variable stars we found in our data. Among our discoveries we count 52 new eclipsing binaries and 24 other periodic variable stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/3325
- Title:
- 2 new candidate luminous blue variables
- Short Name:
- J/MNRAS/421/3325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two new Galactic candidate luminous blue variable (LBV) stars via detection of circular shells (typical of confirmed and candidate LBVs) and follow-up spectroscopy of their central stars. The shells were detected at 22um in the archival data of the Mid-Infrared All Sky Survey carried out with the Wide-field Infrared Survey Explorer (WISE). Follow-up optical spectroscopy of the central stars of the shells conducted with the renewed Southern African Large Telescope (SALT) showed that their spectra are very similar to those of the well-known LBVs P Cygni and AG Car, and the recently discovered candidate LBV MN112, which implies the LBV classification for these stars as well.
- ID:
- ivo://CDS.VizieR/J/AJ/145/132
- Title:
- New catalog of 1578 {delta} Scuti stars
- Short Name:
- J/AJ/145/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present statistical characteristics of 1578 {delta} Scuti stars including nearby field stars and cluster member stars within the Milky Way. We obtained 46% of these stars (718 stars) from work by Rodriguez and collected the remaining 54% of stars (860 stars) from other literature. We updated the entries with the latest information of sky coordinates, color, rotational velocity, spectral type, period, amplitude, and binarity. The majority of our sample is well characterized in terms of typical period range (0.02-0.25days), pulsation amplitudes (<0.5mag), and spectral types (A-F type). Given this list of {delta} Scuti stars, we examined relations between their physical properties (i.e., periods, amplitudes, spectral types, and rotational velocities) for field stars and cluster members, and confirmed that the correlations of properties are not significantly different from those reported in Rodriguez's work. All the {delta} Scuti stars are cross-matched with several X-ray and UV catalogs, resulting in 27 X-ray and 41 UV-only counterparts. These counterparts are interesting targets for further study because of their uniqueness in showing {delta} Scuti-type variability and X-ray/UV emission at the same time. The compiled catalog can be accessed through the Web interface http://stardb.yonsei.ac.kr/DeltaScuti.
