- ID:
- ivo://CDS.VizieR/J/A+A/520/A108
- Title:
- CoRoT 101128793 light curves
- Short Name:
- J/A+A/520/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT (Convection, Rotation and planetary Transits) space mission provides a valuable opportunity to monitor stars with uninterrupted time sampling for up to 150 days at a time. The study of RR Lyrae stars, performed in the framework of the Additional Programmes belonging to the exoplanetary field, will particularly benefit from such dense, long-duration monitoring. We used the CoRoT data of the new RR Lyrae variable CoRoT 101128793 (f_0_=2.119c/d, P=0.4719296d) to provide us with more detailed observational facts to understand the physical process behind the Blazhko phenomenon. The CoRoT data were corrected for one jump and the long term drift. We detected 79 frequencies in the light curve of CoRoT 101128793. The timeseries presented here can be used to identify the main frequency f_0_, its harmonics, the terms related to the Blazhko frequency f_m, two independent terms, and several combination terms. All the 79 frequencies are listed in the file table1.dat. The times of maxima are listed in the file table2.dat.
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- ID:
- ivo://CDS.VizieR/J/A+A/527/A146
- Title:
- CoRoT 0105288363 light curves
- Short Name:
- J/A+A/527/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT - Convection Rotation and Planetary Transits - space mission provides a unique opportunity to monitor RR Lyrae stars with excellent time-sampling, unprecedented photometric precision, and a long time base of 150 days. The pulsation characteristics of RR Lyrae stars rely on robust physics, but we still lack a firm quantitative understanding of the physical mechanisms driving the Blazhko modulation and the long-term changes in their pulsation behavior. We use the high- precision space data of an unknown RR Lyrae star CoRoT ID 0105288363 observed during a second long run centered on the Galaxy -LRc02-, to improve our understanding of the pulsation properties of RR Lyrae stars.
- ID:
- ivo://CDS.VizieR/J/A+A/510/A39
- Title:
- CoRoT light curves of V1127 Aql
- Short Name:
- J/A+A/510/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT space mission - Convection Rotation and Planetary Transits - is a great opportunity for monitoring stars with excellent time-sampling and unprecedented photometric precision for up to 150days. As an important benefit, high-quality RR Lyrae light curves are obtained with a quasi-uninterrupted coverage over several pulsation and Blazhko cycles. The Blazhko effect in RR Lyrae stars is an unsolved problem of astrophysics. We used the high-precision space data to contribute with more precise knowledge to clear up the possible physical processes behind the phenomenon. We applied different period finding techniques including Period04, MuFrAn, PDM and SigSpec. Amplitude and phase modulation were investigated by an analytical function method as well as with the traditional O-C diagrams. The Blazhko modulation frequency is directly detected in the spectrum, as well as its first and second harmonics. It shows the non-linear nature of the Blazhko modulation. Besides the triplets, further higher-order modulation side peaks appear around the pulsation frequency as quintuplet, septuplet, nonuplet, undecaplet, tredecaplet, quindecaplet and septdecaplet structures. Additional frequencies, not belonging to the classical multiplet structures, are detected, and their linear combinations with the fundamental radial mode. We interpret these additional terms as non-radial modes. During the five consecutive Blazhko cycles, there is a shift of the maximum phase around 0.011 pulsation phase which is likely the consequence of a long term modulation.
- ID:
- ivo://CDS.VizieR/B/corot
- Title:
- CoRoT observation log (N2-4.4)
- Short Name:
- B/corot
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CoRoT, a space astronomy mission, has measured photometric micro-variability of stars from minutes to months (up to 150 days) with a high duty cycle (more than 90%). The mission was led by CNES in association with four French laboratories and 7 participating countries and agencies (Austria, Belgium, Brazil, Germany, Spain, and the ESA Science Programme). The satellite was composed of a PROTEUS platform (the 3rd in the series) and a unique instrument: a stellar rapid photometer. It was launched on December 27th 2006 by a Soyuz Rocket, from Baikonour. The mission has lasted almost 6 years (the nominal 3-year duration and a 3-year extension) and has observed more than 160 000 stars. It stopped sending data on November 2nd 2012. Two regions of the sky were accessible for long period of time: circles of 10 degrees centered on the equator around alpha=06:50 and alpha=18:50. They were called the CoRoT eyes: the "anticenter" and the "center eye" (as they are approximately in these directions). Each pointing covers 1.4x2.8 square degrees within one of those CoRoT eyes. The original scientific objectives were focussed on the study of stellar pulsations (asteroseismology) to probe the internal structure of stars, and the detection of small exoplanets through their "transit" in front of their host star, and the measurement of their size. This lead to introduce two modes of observations, working simultaneously: - The "bright star" mode dedicated to very precise seismology of a small sample of bright and closeby stars - The "faint star" mode, observing a very large number of stars at the same time, to detect transits, which are rare events, as they imply the alignment of the star, the planet and the observer. The large amount of data gathered in this mode turned out to be extremely fruitful for many topics of stellar physics. Beyond these two initial objectives, CoRoT data revealed stellar variability associated with various other phenomena: granulation, rotational modulation by spots associated with magnetic activity, oblateness induced by a nearby companion star, ... The data of this CoRoT CDS archive correspond to the legacy release V4.4 of CoRoT N2 data. A complete description can be found in the "CoRoTN2versions_30sept2014.pdf" document available on the vizier ftp as well as on project websites listed in the "See also" field below. Other archives provide an access to the CoRoT data at different levels, or to complementary catalogues - the CoRoT IAS archive at idoc-corot.ias.u-psud.fr/ and mirrors of this archive at exoplanetarchive.ipac.caltech.edu/applications/ETSS/CoRoT_exo_index.html and at exoplanetarchive.ipac.caltech.edu/applications/ETSS/CoRoT_astero_index.html - archive at https://sipad-corot.cnes.fr/ or at the CoRoT IAS archive, but they require a deep understanding of the instrument and the observation conditions to be scientifically helpful. - Raw data N0 are available upon request at the CoRoT CNES archive. - Complementary data on the CoRoT targets, obtained through ground based complementary observations, can be found in :
- ID:
- ivo://CDS.VizieR/J/A+A/629/A94
- Title:
- CO spectra of 49 semi-regular variables
- Short Name:
- J/A+A/629/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to study the main properties of a volume-limited unbiased sample of well characterized semi-regular variables (SRs) in order to clarify important issues that need to be further explained, such as the formation of axially symmetric planetary nebulae (PNe) from spherical circumstellar envelopes (CSEs) that takes place during the mass loss process along the AGB phase. We present new high S/N IRAM 30m observations of the ^12^CO J=2-1, ^12^CO J=1-0, and ^13^CO J=1-0 lines, in a volume-limited sample of SRs for which the Hipparcos distances are between 100-500 pc and declinations above -25{deg}. We analyzed the data by characterizing the main properties of the CSEs. The ^12^CO J=2-1 data have been used to study the profiles, while the ^12^CO J=1-0 data have been used to estimate mass-loss rates for the complete sample. Moreover, the ^12^CO J=2-1 line has been used to determine the possible structures responsible for such profiles. We have classified the sources into four groups according to the different profiles and final gas expansion velocities. Type 1 and 2 profiles are broad and narrow symmetric lines, respectively. Type 1 profiles, furthermore, are more related to standard spherically symmetric envelopes already studied. Type 3 profiles, on the contrary, are strange profiles with very pronounced asymmetries. Type 4 profiles, finally, are those which show two different components: a narrow line profile superimposed on a broad pedestal component. We find that for sources which show this kind of profile, with two different components, the variation amplitude is very low, what means that these SRs do not have a well developed inner envelope differentiated from the outer one. Interestingly, we report a moderate correlation between mass-loss rates and ^12^CO J=1-0/^12^CO J=2-1 line intensity ratios for O-rich SRs, suggesting a different behaviour between C- and O-rich SRs. By using SHAPE+shapemol, we find a unified simple model based on an oblate spheroid, placed in different orientations, that may explain all the ^12^CO profiles in the sample, indicating that the gas expansion is, in general, predominantly equatorial. Moreover, in order to explain the type 4 profiles, we define an extra component which may somehow be a biconical structure or similar according to the structures already found in this kind of sources. Type 1 and 2 profiles, curiously, may also be explained by standard spherically symmetric envelopes, but often requiring anomalously low velocities. Type 3 and 4 profiles, however, need axial symmetry to be explained. We conclude that most circumstellar shells around SRs show axial, strongly non-spherical symmetry. More interferometric observations are needed in order to make firm conclusions about mass-loss processes and possible morphologies of SRs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/459/1170
- Title:
- Coulour-Period relation for Cepheids
- Short Name:
- J/MNRAS/459/1170
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare mid-infrared (IR) 3.6 and 4.5{mu}m Warm Spitzer observations for Cepheids in the Milky Way and the Large and Small Magellanic Clouds. Using models, we explore in detail the effect of the CO rotation-vibration band-head at 4.6{mu}m on the mid-IR photometry. We confirm the temperature sensitivity of the CO band-head at 4.6{mu}m and find no evidence for an effect at 3.6{mu}m. We compare the ([3.6]-[4.5]) period-colour relations in the MW, LMC and SMC. The slopes of the period-colour relations for the three galaxies are in good agreement, but there is a trend in zero-point with metallicity, with the lowest metallicity Cepheids having redder mid-IR colours. Finally, we present a colour-[Fe/H] relation based on published spectroscopic metallicities. This empirical relation, calibrated to the metallicity system of Genovali et al., demonstrates that the ([3.6]-[4.5]) colour provides a reliable metallicity indicator for Cepheids, with a precision comparable to current spectroscopic determinations.
- ID:
- ivo://CDS.VizieR/J/A+AS/108/595
- Title:
- CP2 SrCrEu stars light variation
- Short Name:
- J/A+AS/108/595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/566/A95
- Title:
- C-rich giants synthetic spectrophotometry. IV
- Short Name:
- J/A+A/566/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution and spectral properties of stars on the asymptotic giant branch (AGB) are significantly affected by massloss through dusty stellar winds. Dynamic atmosphere and wind models are an essential tool for studying these evolved stars, both individually and as members of stellar populations, to understand their contribution to the integrated light and chemical evolution of galaxies. This paper is part of a series with the purpose of testing state-of-the-art atmosphere and wind models of C-type AGB stars against observations, and making them available to the community for use in various theoretical and observational studies. We have computed low-resolution spectra and photometry (in the wavelength range 0.35-25um) for a grid of 540 dynamic models with stellar parameters typical of solar-metallicity C-rich AGB stars and with a range of pulsation amplitudes. The models cover the dynamic atmosphere and dusty outflow (if present), assuming spherical symmetry, and taking opacities of gas-phase species and dust grains consistently into account. To characterize the time-dependent dynamic and photometric behaviour of the models in a concise way we defined a number of classes for models with and without winds.Results. Comparisons with observed data in general show a quite satisfactory agreement for example regarding mass-loss rates vs. (J-K) colours or K magnitudes vs. (J-K) colours. Some exceptions from the good overall agreement, however, are found and attributed to the range of input parameters (e.g. relatively high carbon excesses) or intrinsic model assumptions (e.g. small particle limit for grain opacities). While current results indicate that some changes in model assumptions and parameter ranges should be made in the future to bring certain synthetic observables into better agreement with observations, it seems unlikely that these pending improvements will significantly affect the mass-loss rates of the models.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/3688
- Title:
- CSS Periodic Variable Star Catalogue
- Short Name:
- J/MNRAS/469/3688
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we present the results from our analysis of six years of optical photometry taken by the Siding Spring Survey (SSS). This completes a search for periodic variable stars within the 30,000 square degrees of the sky covered by the Catalina Surveys. The current analysis covers 81 million sources with declinations between -20 and -75 degrees with median magnitudes in the range 11<V<19.5. We find approximately 34,000 new periodic variable stars in addition to the ~9,000 RR Lyrae that we previously discovered in SSS data. This brings the total number of periodic variables identified in Catalina data to ~110,000. The new SSS periodic variable stars mainly consist of eclipsing binaries, RR Lyrae, LPVs, RS CVn stars, {delta} Scutis and Anomalous Cepheids. By cross-matching these variable stars with those from prior surveys, we find that ~90% of the sources are new discoveries and recover ~95% of the known periodic variables in the survey region. For the known sources, we find excellent agreement between our catalogue and prior values of luminosity, period and amplitude. However, we find many variable stars that had previously been misclassified. Examining the distribution of RR Lyrae, we find a population associated with the Large Magellanic Cloud (LMC) that extends more than 20 degrees from its center confirming recent evidence for the existence of a very extended stellar halo in the LMC. By combining SSS photometry with Dark Energy Survey data, we identify additional LMC halo RR Lyrae, thus confirming the significance of the population.
- ID:
- ivo://CDS.VizieR/J/ApJ/892/112
- Title:
- CTIO/DECam LCs for Galactic bulge variable stars
- Short Name:
- J/ApJ/892/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the advent of the Legacy Survey of Space and Time, time-domain astronomy will be faced with an unprecedented volume and rate of data. Real-time processing of variables and transients detected by such large-scale surveys is critical to identifying the more unusual events and allocating scarce follow-up resources efficiently. We develop an algorithm to identify these novel events within a given population of variable sources. We determine the distributions of magnitude changes (dm) over time intervals (dt) for a given passband f, p_f_^(dm|dt)^, and use these distributions to compute the likelihood of a test source being consistent with the population or being an outlier. We demonstrate our algorithm by applying it to the DECam multiband time-series data of more than 2000 variable stars identified by Saha+ (2019, J/ApJ/874/30) in the Galactic Bulge that are largely dominated by long-period variables and pulsating stars. Our algorithm discovers 18 outlier sources in the sample, including a microlensing event, a dwarf nova, and two chromospherically active RS CVn stars, as well as sources in the blue horizontal branch region of the color-magnitude diagram without any known counterparts. We compare the performance of our algorithm for novelty detection with the multivariate Kernel Density Estimator and Isolation Forest on the simulated PLAsTiCC data set. We find that our algorithm yields comparable results despite its simplicity. Our method provides an efficient way for flagging the most unusual events in a real-time alert-broker system.
