- ID:
- ivo://CDS.VizieR/J/A+A/415/521
- Title:
- BVRIJK and velocities for MC Cepheids
- Short Name:
- J/A+A/415/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high precision and well sampled BVRIJK light curves and radial velocity curves for a sample of five (+1) Cepheids in the SMC. In addition we present radial velocity curves for five (+1) Cepheids in the LMC. The low metallicity ([Fe/H]~-0.7) SMC stars have been selected for use in a Baade-Wesselink type analysis to constrain the metallicity effect on the Cepheid Period-Luminosity relation. The stars have periods of around 15 days so they are similar to the Cepheids observed by the Extragalactic Distance Scale Key Project on the Hubble Space Telescope. We show that the stars are representative of the SMC Cepheid population at that period and thus will provide a good sample for the proposed analysis. The actual Baade-Wesselink analysis are presented in Strom et al., 2004, Cat. <J/A+A/415/531>.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/542/A78
- Title:
- BVRI light curves and RV curves of 65 UMa
- Short Name:
- J/A+A/542/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of stellar multiple systems provides us with important information about the stellar formation processes and can help us to estimate the multiplicity fraction in the Galaxy. 65 UMa belongs to a rather small group of stellar systems of higher multiplicity, whose inner and outer orbits are well-known. This allows us to study the long-term stability and evolution of the orbits in these systems. We obtained new photometric and spectroscopic data that when combined with interferometric data enables us to analyze the system 65 UMa and determine its basic physical properties.
- ID:
- ivo://CDS.VizieR/J/AJ/130/234
- Title:
- BVRI photometry and radial velocities of AV Del
- Short Name:
- J/AJ/130/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic and BVRI photometric observations of the double-lined eclipsing binary AV Del (period=3.85days) conducted over six observing seasons.
- ID:
- ivo://CDS.VizieR/J/ApJ/764/114
- Title:
- BVRI photometry of stars in Orion A
- Short Name:
- J/ApJ/764/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend our previous study of the stellar population of L1641, the lower-density star-forming region of the Orion A cloud south of the dense Orion Nebula Cluster (ONC), with the goal of testing whether there is a statistically significant deficiency of high-mass stars in low-density regions. Previously, we compared the observed ratio of low-mass stars to high-mass stars with theoretical models of the stellar initial mass function (IMF) to infer a deficiency of the highest-mass stars in L1641. We expand our population study to identify the intermediate-mass (late B to G) L1641 members in an attempt to make a more direct comparison with the mass function of the nearby ONC. The spectral-type distribution and the K-band luminosity function of L1641 are similar to those of the ONC, but problems of incompleteness and contamination prevent us from making a detailed test for differences. We limit our analysis to statistical tests of the ratio of high-mass to low-mass stars, which indicate a probability of only 3% that the ONC and the southern region of L1641 were drawn from the same population, supporting the hypothesis that the upper-mass end of the IMF is dependent on environmental density.
- ID:
- ivo://CDS.VizieR/J/ApJ/816/L4
- Title:
- Candidate BHB stars in Ophiuchus stream
- Short Name:
- J/ApJ/816/L4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Ophiuchus stellar stream presents a dynamical puzzle: its old stellar populations (~12Gyr) cannot be reconciled with (1) its orbit in a simple model for the Milky Way potential and (2) its short angular extent, both of which imply that the observed stream formed within the last <1Gyr. Recent theoretical work has shown that streams on chaotic orbits may abruptly fan out near their apparent ends; stars in these fans are dispersed in both position and velocity and may be difficult to associate with the stream. Here we present the first evidence of such stream-fanning in the Ophiuchus stream, traced by four blue horizontal branch stars beyond the apparent end of the stream. These stars stand out from the background by their high velocities (v_los_>230km/s) against ~40 other stars: their velocities are comparable to those of the stream, but would be exceptional if they were unrelated halo stars. Their positions and velocities are, however, inconsistent with simple extrapolation of the observed cold, high-density portion of the stream. These observations suggest that stream-fanning may be a real, observable effect and, therefore, that Ophiuchus may be on a chaotic orbit. They also show that the Ophiuchus stream is more extended and hence dynamically older than previously thought, easing the stellar population versus dynamical age tension.
- ID:
- ivo://CDS.VizieR/J/ApJS/234/31
- Title:
- Carbon stars from LAMOST using machine learning
- Short Name:
- J/ApJS/234/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present a catalog of 2651 carbon stars from the fourth Data Release (DR4) of the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST). Using an efficient machine-learning algorithm, we find these stars from more than 7 million spectra. As a by-product, 17 carbon-enhanced metal- poor turnoff star candidates are also reported in this paper, and they are preliminarily identified by their atmospheric parameters. Except for 176 stars that could not be given spectral types, we classify the other 2475 carbon stars into five subtypes: 864 C-H, 226 C-R, 400 C-J, 266 C-N, and 719 barium stars based on a series of spectral features. Furthermore, we divide the C-J stars into three subtypes, C-J(H), C-J(R), and C-J(N), and about 90% of them are cool N-type stars as expected from previous literature. Besides spectroscopic classification, we also match these carbon stars to multiple broadband photometries. Using ultraviolet photometry data, we find that 25 carbon stars have FUV detections and that they are likely to be in binary systems with compact white dwarf companions.
- ID:
- ivo://CDS.VizieR/J/other/Ap/41.1
- Title:
- Catalog of barred galaxies
- Short Name:
- J/other/Ap/41.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of barred spiral galaxies of types SB and SAB with B_T_=<13.5 and DE>-10{deg} has been compiled. Some parameters of these galaxies are given.
- ID:
- ivo://CDS.VizieR/J/AJ/153/95
- Title:
- Catalog of Suspected Nearby Young Stars
- Short Name:
- J/AJ/153/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new nearby young moving group (NYMG) kinematic membership analysis code, LocAting Constituent mEmbers In Nearby Groups (LACEwING), a new Catalog of Suspected Nearby Young Stars, a new list of bona fide members of moving groups, and a kinematic traceback code. LACEwING is a convergence-style algorithm with carefully vetted membership statistics based on a large numerical simulation of the Solar Neighborhood. Given spatial and kinematic information on stars, LACEwING calculates membership probabilities in 13 NYMGs and three open clusters within 100 pc. In addition to describing the inputs, methods, and products of the code, we provide comparisons of LACEwING to other popular kinematic moving group membership identification codes. As a proof of concept, we use LACEwING to reconsider the membership of 930 stellar systems in the Solar Neighborhood (within 100 pc) that have reported measurable lithium equivalent widths. We quantify the evidence in support of a population of young stars not attached to any NYMGs, which is a possible sign of new as-yet-undiscovered groups or of a field population of young stars.
- ID:
- ivo://CDS.VizieR/V/131
- Title:
- Catalogue of LMC stars
- Short Name:
- V/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue is a compilation of the original data related to stars in the Large Magellanic Cloud (LMC); it concerns essentially the stars brighter than m_pg_=13.5. The list includes many comments (in English and French) about errors, identification problems, or membership of 4011 stars.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A122
- Title:
- Cetus dSph stellar chemo-kinematics
- Short Name:
- J/A+A/618/A122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cetus is an isolated, dwarf spheroidal (dSph) galaxy at a distance of 755kpc. In order to quantify its stellar chemo-kinematical properties, we observed individual red giants branch stars in Cetus with the Very Large Telescope (VLT) FORS2 instrument, in Mask eXchange Unit (MXU) configuration. The kinematic analysis shows that Cetus is a mainly pressure-supported ({sigma}_v_=11.0^+1.6^_-1.3_km/s), dark-matter-dominated system (M_1/2_/L_V_=23.9^+9.7^_-8.9_M_{sun}_/L_{sun}_) with no significant signs of internal rotation. We find Cetus to be a metal-poor system with a significant metallicity spread (median [Fe/H]=-1.71dex, median-absolute-deviation =0.49dex), as expected for its stellar mass. We report the presence of a mild metallicity gradient compatible with those found in other dSphs of the same luminosity; we trace the presence of a stellar population gradient also in the spatial distribution of stars in different evolutionary phases in ancillary photometric data. There are tentative indications of two chemo-kinematically distinct sub-populations, with the more metal-poor stars showing a hotter kinematics than the metal-richer ones. Our results add Cetus to the growing scatter in stellar-dark matter halo properties in low-mass galactic systems. The presence of a metallicity gradient akin to those found in similar systems inhabiting different environments may hint at metallicity gradients in Local Group early-type dwarfs being driven by internal mechanisms.