- ID:
- ivo://CDS.VizieR/J/A+A/504/959
- Title:
- Amplitudes of single-mode Cepheids
- Short Name:
- J/A+A/504/959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dependence of amplitude on the pulsation period differs from other Cepheid-related relationships. We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, Rc, and Ic photometric bands and pulsational radial velocity variations facilitate investigations of previously poorly studied interrelations between observable amplitudes. The effects of both binarity and metallicity on the observed amplitude, and the dichotomy between short- and long-period Cepheids can both be studied. A homogeneous data set was created that contains basic physical and phenomenological properties of 369 Galactic Cepheids. Pulsation periods were revised and amplitudes were determined by the Fourier method. P-A graphs were constructed and an upper envelope to the data points was determined in each graph. Correlations between various amplitudes and amplitude-related parameters were searched for, using Cepheids without known companions.
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- ID:
- ivo://CDS.VizieR/J/AJ/140/1475
- Title:
- ARAUCARIA: NGC 7793 Cepheids
- Short Name:
- J/AJ/140/1475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the first time, we have detected Cepheid variables in the Sculptor Group spiral galaxy NGC 7793. From wide-field images obtained in the optical V and I bands on 56 nights in 2003-2005, we have discovered 17 long-period (24-62 days) Cepheids whose periods and mean magnitudes define tight period-luminosity relations. We use the (V-I) Wesenheit index to determine a reddening-free true distance modulus to NGC 7793 of 27.68+/-0.05mag (internal error) +/-0.08mag (systematic error).
- ID:
- ivo://CDS.VizieR/J/ApJ/648/375
- Title:
- Araucaria: NGC 3109 Cepheids JK phot.
- Short Name:
- J/ApJ/648/375
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared J- and K-band photometry of 77 Cepheid variables in the Local Group galaxy NGC 3109. Combining our data with the previously published optical V- and I-band photometry of Cepheids in this galaxy, we derive an accurate distance and interstellar reddening toward NGC 3109.
- ID:
- ivo://CDS.VizieR/J/AJ/132/2556
- Title:
- ARAUCARIA project: Cepheids in NGC 55
- Short Name:
- J/AJ/132/2556
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have detected, for the first time, Cepheid variables in the Sculptor Group SB(s)m galaxy NGC 55. From wide-field images obtained in the optical V and I bands during 77 nights in 2002-2003, we have found 143 Cepheids with periods ranging from 5.6 to 175.9 days; 133 of these objects have periods longer than 10 days, making NGC 55 to date the galaxy with the largest known number of long-period Cepheids in the Sculptor Group.
- ID:
- ivo://CDS.VizieR/J/AJ/134/594
- Title:
- Araucaria project: Cepheids in WLM galaxy
- Short Name:
- J/AJ/134/594
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted an extensive wide-field imaging survey for Cepheid variables in the Local Group irregular galaxy WLM. From data obtained on 101 nights, we have discovered 60 Cepheids, which include 14 of the 15 Cepheid variables previously detected by Sandage and Carlson. Our Cepheid survey in WLM should be practically complete down to a period of 3-days. Importantly, we have found for the first time a long-period Cepheid (P=54.2-days) in this galaxy, alleviating the problem that WLM with its many blue, massive stars does not contain Cepheids with periods longer than about 10-days.
- ID:
- ivo://CDS.VizieR/J/ApJ/672/266
- Title:
- ARAUCARIA project: NGC 55 Cepheids JK magnitudes
- Short Name:
- J/ApJ/672/266
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained deep images in the near-infrared J and K filters of four fields in the Sculptor group spiral galaxy NGC 55 with the ESO VLT and ISAAC camera. For 40 long-period Cepheid variables in these fields, which were recently discovered by Pietrzyski et al., we have determined mean J and K magnitudes from observations at two epochs, and derived distance moduli from the observed period-luminosity (PL) relations in these bands.
- ID:
- ivo://CDS.VizieR/J/ApJ/647/1056
- Title:
- ARAUCARIA project : NGC 6822 Cepheid variables
- Short Name:
- J/ApJ/647/1056
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured near-infrared magnitudes in the J and K bands for 56 Cepheid variables in the Local Group galaxy NGC 6822 with well-determined periods and optical light curves in the V and I bands. Using the template light-curve approach of Soszyski and coworkers (2005PASP..117..823S), accurate mean magnitudes were obtained from these data, which allowed us to determine with unprecedented accuracy the distance to NGC 6822 from a multi-wavelength period-luminosity solution in the VIJK bands.
- ID:
- ivo://CDS.VizieR/J/AJ/128/2815
- Title:
- ARAUCARIA project: NGC 6822 Cepheid variables
- Short Name:
- J/AJ/128/2815
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained mosaic images of NGC 6822 in the V and I bands on 77 nights. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, and we have found 116 such variables with periods ranging from 1.7 to 124 days. We used the long-period (>5.6 days) Cepheids to establish the period-luminosity (PL) relations in V, I, and in the reddening-independent Wesenheit index, which are all very tightly defined.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1167
- Title:
- ARAUCARIA project : NGC 300 Cepheid Variables. II
- Short Name:
- J/AJ/128/1167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VI data, derive improved periods and mean magnitudes for the variables, and construct period-luminosity relations in the V, I, and the reddening-independent V-I Wesenheit bands using 58 Cepheid variables with periods between 11 and 90 days.
- ID:
- ivo://CDS.VizieR/J/MNRAS/505/6051
- Title:
- Arecibo sample variability properties
- Short Name:
- J/MNRAS/505/6051
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of a near-infrared (NIR) monitoring program carried out between 1999 and 2005 to determine the variability properties of the `Arecibo sample of OH/IR stars'. The sample consists of 385 IRAS-selected Asymptotic Giant Branch (AGB) candidates, for which their O-rich chemistry has been proven by the detection of 1612 MHz OH maser emission. The monitoring data was complemented by data collected from public optical and NIR surveys. We fitted the light curves obtained in the optical and NIR bands with a model using an asymmetric cosine function, and derived a period for 345 sources ~90% of the sample). Based on their variability properties, most of the Arecibo sources are classified as long-period large-amplitude variable stars (LPLAV), 4% as (candidate) post-AGB stars, and 3% remain unclassified although they are likely post-AGB stars or highly obscured AGB stars. The period distribution of the LPLAVs peaks at ~400d, with periods between 300 and 800d for most of the sources, and has a long tail up to ~2100d. Typically, the amplitudes are between 1 and 3 mag in the NIR and between 2 and 6 mag in the optical. We find correlations between periods and amplitudes, with larger amplitudes associated to longer periods, as well as between the period and the infrared colours, with the longer periods linked to the redder sources. Among the post-AGB stars, the light curve of IRAS 19566+3423 was exceptional, showing a large systematic increase (>0.4mag/yr) in K-band brightness over 7 years.
- ID:
- ivo://CDS.VizieR/II/366
- Title:
- ASAS-SN catalog of variable stars
- Short Name:
- II/366
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to routinely monitor the whole sky with a cadence of ~2-3d down to V<~17mag. ASAS-SN has monitored the whole sky since 2014, collecting ~100-500 epochs of observations per field. The V-band light curves for candidate variables identified during the search for supernovae are classified using a random forest classifier and visually verified. In Paper I (Jayasinghe+ 2018MNRAS.477.3145J), we present a catalogue of 66179 bright, new variable stars discovered during our search for supernovae, including 27479 periodic variables and 38700 irregular variables. In paper II (Jayasinghe+ 2019MNRAS.486.1907J), We extracted the ASAS-SN light curves of ~412000 variable stars previously discovered by other surveys and in the VSX catalogue. In paper III (Jayasinghe+ 2019MNRAS.485..961J), we extracted the ASAS-SN light curves of ~1.3 million sources within 18deg of the Southern Ecliptic Pole. These sources are within the southern TESS CVZ and will have well-sampled TESS light curves.
- ID:
- ivo://CDS.VizieR/J/AcA/59/33
- Title:
- ASAS. Variable stars catalog in Kepler field.
- Short Name:
- J/AcA/59/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a result of the analysis of VI photometry obtained during the first 17-month observations in the ASAS3-North station. The variable stars we present are divided into eleven groups according to the presented variability; the groups are briefly discussed. The catalog is intended to be a source of information for target selection process and follow-up programs.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/21
- Title:
- ASTEP catalog of EB* and variable stars
- Short Name:
- J/ApJS/226/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the large photometric database of the ASTEP program, whose primary goal was to detect exoplanets in the southern hemisphere from Antarctica, to search for eclipsing binaries (EcBs) and variable stars. 673 EcBs and 1166 variable stars were detected, including 31 previously known stars. The resulting online catalogs give the identification, the classification, the period, and the depth or semi-amplitude of each star. Data and light curves for each object are available at http://astep-vo.oca.eu/.
- ID:
- ivo://CDS.VizieR/J/A+A/632/L6
- Title:
- AT 2018hso light curves and spectra
- Short Name:
- J/A+A/632/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The absolute magnitudes of luminous red novae (LRNe) are intermediate between those of novae and supernovae (SNe), and show a relatively homogeneous spectro-photometric evolution. Although they were thought to derive from core instabilities in single stars, there is growing support for the idea that they are triggered by binary interaction that possibly ends with the merging of the two stars. AT 2018hso is a new transient showing transitional properties between those of LRNe and the class of intermediate-luminosity red transients (ILRTs) similar to SN 2008S. Through the detailed analysis of the observed parameters, our study support that it actually belongs to the LRN class and was likely produced by the coalescence of two massive stars. We obtained ten months of optical and near-infrared photometric monitoring, and 11 epochs of low-resolution optical spectroscopy of AT 2018hso. We compared its observed properties with those of other ILRTs and LRNe. We also inspected the archival Hubble Space Telescope (HST) images obtained about 15 years ago to constrain the progenitor properties. The light curves of AT 2018hso show a first sharp peak (reddening-corrected M_r_=13.93mag), followed by a broader and shallower second peak that resembles a plateau in the optical bands. The spectra dramatically change with time. Early-time spectra show prominent Balmer emission lines and a weak [CaII] doublet, which is usually observed in ILRTs. However, the strong decrease in the continuum temperature, the appearance of narrow metal absorption lines, the great change in the H{alpha} strength and profile, and the emergence of molecular bands support an LRN classification. The possible detection of a M_I_~8mag source at the position of AT 2018hso in HST archive images is consistent with expectations for a pre-merger massive binary, similar to the precursor of the 2015 LRN in M101. We provide reasonable arguments to support an LRN classification for AT 2018hso. This study reveals growing heterogeneity in the observables of LRNe than has been thought previously, which is a challenge for distinguishing between LRNe and ILRTs. This suggests that the entire evolution of gap transients needs to be monitored to avoid misclassifications.
- ID:
- ivo://CDS.VizieR/J/AJ/160/32
- Title:
- beta Cephei light curves from KELT project
- Short Name:
- J/AJ/160/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for Galactic {beta} Cephei stars, which are massive pulsating stars with both pressure modes and mixed modes. Thus, these stars can serve as benchmarks for seismological studies of the interiors of massive stars. We conducted the search by performing a frequency analysis on the optical light curves of known O- and B-type stars with data from the Kilodegree Extremely Little Telescope exoplanet survey. We identify 113 {beta} Cephei stars, of which 86 are new discoveries, which altogether represent a 70% increase in the number currently known. An additional 97 candidates are identified. Among our targets, we find five new eclipsing binaries and 22 stars with equal frequency spacings suggestive of rotational splitting of nonradial pulsation modes. Candidates for runaway stars among our targets and a number of interesting individual objects are discussed. Most of the known and newly discovered {beta} Cephei stars will be observed by the Transiting Exoplanet Survey Satellite mission, providing by far the most comprehensive observational data set of massive main-sequence pulsating stars of sufficient quality for detailed asteroseismic studies. Future analysis of these light curves has the potential to dramatically increase our understanding of the structure of stellar interiors and the physical processes taking place therein.
- ID:
- ivo://CDS.VizieR/J/MNRAS/508/2226
- Title:
- Binary central star of V510 Pup
- Short Name:
- J/MNRAS/508/2226
- Date:
- 19 Jan 2022 13:43:04
- Publisher:
- CDS
- Description:
- Current models predict that binary interactions are a major ingredient in the formation of bipolar planetary nebulae (PNe) and pre-planetary nebulae (PPNe). Despite years of radial velocity (RV) monitoring, the paucity of known binaries amongst the latter systems means data are insufficient to examine this relationship in detail. In this work, we report on the discovery of a long-period (P=2654+/-124d) binary at the centre of the Galactic bipolar PPN IRAS 08005-2356 (V510 Pup), determined from long-term spectroscopic and near-infrared time-series data. The spectroscopic orbit is fitted with an eccentricity of 0.36+/-0.05, which is similar to that of other long-period post-AGB binaries. Time-resolved H{alpha} profiles reveal high-velocity outflows (jets) with deprojected velocities up to 231^+31^_-27_km/s seen at phases when the luminous primary is behind the jet. The outflow traced by H{alpha} is likely produced via accretion on to a main-sequence companion, for which we calculate a mass of 0.63+/-0.13M_{sun}_. This discovery is one of the first cases of a confirmed binary PPN and demonstrates the importance of high-resolution spectroscopic monitoring surveys using large telescopes in revealing binarity among these systems.
- ID:
- ivo://CDS.VizieR/J/AJ/152/16
- Title:
- Bolometric flux estimation for cool evolved stars
- Short Name:
- J/AJ/152/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Estimation of bolometric fluxes (F_BOL_) is an essential component of stellar effective temperature determination with optical and near-infrared interferometry. Reliable estimation of F_BOL_ simply from broadband K-band photometry data is a useful tool in those cases were contemporaneous and/or wide-range photometry is unavailable for a detailed spectral energy distribution (SED) fit, as was demonstrated in Dyck et al. Recalibrating the intrinsic F_BOL_ versus observed F_2.2{mu}m_ relationship of that study with modern SED fitting routines, which incorporate the significantly non-blackbody, empirical spectral templates of the INGS spectral library (an update of the library in Pickles) and estimation of reddening, serves to greatly improve the accuracy and observational utility of this relationship. We find that F_BOL_ values predicted are roughly 11% less than the corresponding values predicted in Dyck et al., indicating the effects of SED absorption features across bolometric flux curves.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/L25
- Title:
- Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR)
- Short Name:
- J/ApJ/821/L25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 947 radial velocities of RR Lyrae variable stars in four fields located toward the Galactic bulge, observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR). We show that these RR Lyrae stars (RRLs) exhibit hot kinematics and null or negligible rotation and are therefore members of a separate population from the bar/pseudobulge that currently dominates the mass and luminosity of the inner Galaxy. Our RRLs predate these structures and have metallicities, kinematics, and spatial distribution that are consistent with a "classical" bulge, although we cannot yet completely rule out the possibility that they are the metal-poor tail of a more metal-rich ([Fe/H]~-1dex) halo-bulge population.
- ID:
- ivo://CDS.VizieR/J/other/ApSS/363.127
- Title:
- Bulge RR Lyrae VVVDR4 photometry
- Short Name:
- J/other/ApSS/363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study's objective was to exploit infrared VVV (VISTA Variables in the Via Lactea) photometry for high latitude RRab stars to establish an accurate Galactic Centre distance. RRab candidates were discovered and reaffirmed (n=4194) by matching Ks photometry with templates via chisq minimization, and contaminants were reduced by ensuring targets adhered to a strict period-amplitude (Ks) trend and passed the Elorietta et al. (2016A&A...595A..82E) classifier. The distance to the Galactic Centre was determined from a high latitude Bulge subsample (|b|>4, RGC=8.30+/-0.36kpc, random uncertainty is relatively negligible), and importantly, the comparatively low color-excess and uncrowded location mitigated uncertainties tied to the extinction law, the magnitude-limited nature of the analysis, and photometric contamination. Circumventing those problems resulted in a key uncertainty being the MKs relation, which was derived using LMC RRab stars (MKs=-(2.66+/-0.06)logP-(1.03+/-0.06), (J-Ks)0=(0.31+/-0.04)logP +(0.35+/-0.02), assuming mu0LMC=18.43). The Galactic Centre distance was not corrected for the cone-effect. Lastly, a new distance indicator emerged as brighter overdensities in the period-magnitude-amplitude diagrams analyzed, which arise from blended RRab and red clump stars. Blending may thrust faint extragalactic variables into the range of detectability.
- ID:
- ivo://CDS.VizieR/J/A+A/465/943
- Title:
- BVI and RV curves of 5 eclipsing binaries
- Short Name:
- J/A+A/465/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We detected tertiary components of close binaries from spectroscopy and light curve modelling, investigated the light-travel time effect and the possibility of magnetic activity cycles, measured mass ratios for unstudied systems, and derived absolute parameters. We carried out new photometric and spectroscopic observations of five bright close eclipsing binaries, predominantly in the southern skies. We obtained full Johnson BV light curves, which were modelled with the Wilson-Devinney code. Radial velocities were measured with the cross-correlation method using IAU radial velocity standards as spectral templates. Period changes were studied with the O-C method, utilising published epochs of minimum light (XY Leo) and ASAS photometry (VZ Lib). For three objects (DX Tuc, QY Hya, V870 Ara), absolute parameters have been determined for the first time. We spectroscopically detected the tertiary components in XY Leo and VZ Lib and discovered one in QY Hya. For XY Leo we updated the light-time effect parameters and detected a secondary periodicity of about 5100d in the O-C diagram that may hint at the existence of short-period magnetic cycles. A combination of recent photometric data shows that the orbital period of the tertiary star in VZ Lib is likely to be over 1500d. QY Hya is a semi-detached X-ray active binary in a triple system with K and M-type components, while V870 Ara is a contact binary with the third smallest spectroscopic mass ratio for a W UMa star to date. Being close to the theoretical minimum for contact binaries, this small mass ratio suggests that V870 Ara has the potential of constraining evolutionary scenarios of binary mergers. The inferred distances to these systems are compatible with the Hipparcos parallaxes.