- ID:
- ivo://CDS.VizieR/J/ApJ/634/451
- Title:
- Interstellar Ca II line equivalent widths
- Short Name:
- J/ApJ/634/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We show that the equivalent widths of the well-known interstellar CaII H and K lines can be used to determine the distances to OB stars in our Galaxy. The equivalent widths, measured in the spectra of 147 early-type stars, are strongly related to the Hipparcos parallaxes of those objects. The lines fitted to the parallax-equivalent width data are given by the formulae {pi}=1/[2.78EW(K)+95] and {pi}=1/[4.58EW(H)+102], where {pi} is in arcseconds and EW is in milliangstroms.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/507/833
- Title:
- Interstellar CaII lines for 290 stars
- Short Name:
- J/A+A/507/833
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We attempt to extend the relation between the strengths of the interstellar CaII lines and the distances to early-type stars to objects beyond 1 kiloparsec, with the line saturation taken into account. We measure the CaII K and CaII H equivalent widths, and compute Ca II column densities for 262 lines of sight towards early-type stars with available Hipparcos parallaxes (pi). The targets are located within a few hundred parsecs of the Galactic plane, and span all the range of Galactic longitudes. We fit the N_CaII_ - parallax relation with a function of the form pi=1/(a.N_CaII_+b), using a maximum-likelihood approach to take account of errors in both variables. We use the resultant formula to estimate distances to stars in OB associations and clusters, and compare them to those found in the literature, usually estimated by spectrophotometric methods.
- ID:
- ivo://CDS.VizieR/V/86
- Title:
- Interstellar matter in the Galactic Disk
- Short Name:
- V/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue, developed for a new study of the interstellar medium in the solar vicinity, contains estimations of extinction and distances from reliable UBV data and MK types; special attention was paid to the consistency between spectroscopic and photometric data. There are four sets of 2 files: the main set is named CEDDU (Catalogue of Extinctions and Distances Derived from UBV data). Appendices contain stars with discrepant results: negative colour excesses (exneg), apparently very close stars with heavy reddening (avlar), and apparently very far stars with low reddening (asmal). For each set, one file contains a selection of observational data along with derived and computed parameters, and a second file contains the complete set of observational data. Please refer to the enclosed file "intro" (plain ascii) or "intro.tex" (LaTeX) for a more detailed description of the catalogue and how it was built.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A140
- Title:
- IPHAS-selected classical Be stars
- Short Name:
- J/A+A/591/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a semi-automatic procedure to obtain fundamental physical parameters and distances of classical Be (CBe) stars, based on the Barbier-Chalonge-Divan (BCD) spectrophotometric system. Our aim is to apply this procedure to a large sample of CBe stars detected by the IPHAS photometric survey, to determine their fundamental physical parameters and to explore their suitability as galactic structure tracers. In this paper we describe the methodology used and the validation of the procedure by comparing our results with those obtained from different independent astrophysical techniques for subsamples of stars in common with other studies. We also present a test case study of the galactic structure in the direction of the Perseus Galactic Arm, in order to compare our results with others recently obtained with different techniques and the same sample of stars. We did not find any significant clustering of stars at the expected positions of the Perseus and Outer Galactic Arms, in agreement with previous studies in the same area that we used for verification.
- ID:
- ivo://CDS.VizieR/J/AJ/154/201
- Title:
- IR properties of stellar bowshock nebulae
- Short Name:
- J/AJ/154/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Arcuate infrared nebulae are ubiquitous throughout the Galactic Plane and are candidates for partial shells, bubbles, or bowshocks produced by massive runaway stars. We tabulate infrared photometry for 709 such objects using images from the Spitzer Space Telescope, the Wide-field Infrared Explorer, and the Herschel Space Observatory (HSO). Of the 709 objects identified at 24 or 22 {mu}m, 422 are detected at the HSO 70 {mu}m bandpass. Of these, only 39 are detected at HSO 160 {mu}m. The 70 {mu}m peak surface brightnesses are 0.5-2.5 Jyr/arcmin^2^. Color temperatures calculated from the 24 to 70 {mu}m ratios range from 80 to 400 K. Color temperatures from 70 to 160 {mu}m ratios are systematically lower, 40-200 K. Both of these temperature are, on average, 75% higher than the nominal temperatures derived by assuming that dust is in steady-state radiative equilibrium. This may be evidence of stellar wind bowshocks sweeping up and heating-possibly fragmenting but not destroying-interstellar dust. Infrared luminosity correlates with standoff distance, R_0_, as predicted by published hydrodynamical models. Infrared spectral energy distributions are consistent with interstellar dust exposed to either single radiant energy density, U=10^3^-10^5^ (in more than half of the objects) or a range of radiant energy densities U_min_=25 to U_max_=10^3^-10^5^ times the mean interstellar value for the remainder. Hence, the central OB stars dominate the energetics, making these enticing laboratories for testing dust models in constrained radiation environments. The spectral energy densities are consistent with polycyclic aromatic hydrocarbon fractions q_PAH_~<1% in most objects.
- ID:
- ivo://CDS.VizieR/J/A+A/420/507
- Title:
- Isolated massive white dwarfs catalog
- Short Name:
- J/A+A/420/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of 112 massive isolated white dwarfs, both magnetic and nonmagnetic, with masses M>0.8M_{sun}_. Mass determinations and other parameters of white dwarfs were compiled from the available literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/857/54
- Title:
- JHKs photometry of VVV RR Lyrae stars
- Short Name:
- J/ApJ/857/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RR Lyrae stars (RRLs) are tracers of the Milky Way's fossil record, holding valuable information on its formation and early evolution. Owing to the high interstellar extinction endemic to the Galactic plane, distant RRLs lying at low Galactic latitudes have been elusive. We attained a census of 1892 high-confidence RRLs by exploiting the near-infrared photometric database of the VVV survey's disk footprint spanning ~70{deg} of Galactic longitude, using a machine-learned classifier. Novel data-driven methods were employed to accurately characterize their spatial distribution using sparsely sampled multi-band photometry. The RRL metallicity distribution function (MDF) was derived from their K_s_-band light-curve parameters using machine-learning methods. The MDF shows remarkable structural similarities to both the spectroscopic MDF of red clump giants and the MDF of bulge RRLs. We model the MDF with a multi-component density distribution and find that the number density of stars associated with the different model components systematically changes with both the Galactocentric radius and vertical distance from the Galactic plane, equivalent to weak metallicity gradients. Based on the consistency with results from the ARGOS survey, three MDF modes are attributed to the old disk populations, while the most metal-poor RRLs are probably halo interlopers. We propose that the dominant [Fe/H] component with a mean of -1dex might correspond to the outskirts of an ancient Galactic spheroid or classical bulge component residing in the central Milky Way. The physical origins of the RRLs in this study need to be verified by kinematical information.
- ID:
- ivo://CDS.VizieR/J/ApJ/852/78
- Title:
- JHKs, WISE and Spitzer data of Galactic Cepheids
- Short Name:
- J/ApJ/852/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical Cepheids are well-known and widely used distance indicators. As distance and extinction are usually degenerate, it is important to develop suitable methods to robustly anchor the distance scale. Here, we introduce a near-infrared optimal distance method to determine both the extinction values of and distances to a large sample of 288 Galactic classical Cepheids. The overall uncertainty in the derived distances is less than 4.9%. We compare our newly determined distances to the Cepheids in our sample with previously published distances to the same Cepheids with Hubble Space Telescope parallax measurements and distances based on the IR surface brightness method, Wesenheit functions, and the main-sequence fitting method. The systematic deviations in the distances determined here with respect to those of previous publications is less than 1%-2%. Hence, we constructed Galactic mid-IR period-luminosity (PL) relations for classical Cepheids in the four Wide-Field Infrared Survey Explorer (WISE) bands (W1, W2, W3, and W4) and the four Spitzer Space Telescope bands ([3.6], [4.5], [5.8], and [8.0]). Based on our sample of hundreds of Cepheids, the WISE PL relations have been determined for the first time; their dispersion is approximately 0.10mag. Using the currently most complete sample, our Spitzer PL relations represent a significant improvement in accuracy, especially in the [3.6] band which has the smallest dispersion (0.066mag). In addition, the average mid-IR extinction curve for Cepheids has been obtained: A_W1_/A_Ks_~0.560, A_W2_/A_Ks_~0.479, A_W3_/A_Ks_~0.507, A_W4_/A_Ks_~0.406, A_[3.6]_/A_Ks_~0.481, A_[4.5]_/A_Ks_~0.469, A_[5.8]_/A_Ks_~0.427, and A_[8.0]_/A_Ks_~0.427mag.
- ID:
- ivo://CDS.VizieR/IV/34
- Title:
- K2 Ecliptic Plane Input Catalog (EPIC)
- Short Name:
- IV/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The K2 Mission (Howell+, 2014PASP..126..398H) uses the Kepler spacecraft to obtain high-precision photometry over ~80 day campaigns in the ecliptic plane. The Ecliptic Plane Input Catalog (EPIC) provides coordinates, photometry, and kinematics based on a federation of all-sky catalogs to support target selection and target management for the K2 mission.
- ID:
- ivo://CDS.VizieR/J/AJ/156/234
- Title:
- KELT transit false positive catalog for TESS
- Short Name:
- J/AJ/156/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ~23"/pixel very similar to that of NASA's Transiting Exoplanet Survey Satellite (TESS) - as well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3'. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and photometric precision higher than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ~450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1128 bright stars (6<V<13) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS.
