J/PAZh/38/15ivo://CDS.VizieR/J/PAZh/38/15CDSGontcharov G.A.2016-01-14T13:34:29Z2016-01-14T14:34:14ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frextinctioninterstellar-mediummilky-way-galaxyinterstellar-reddeningMulticolor photometry from the Tycho-2 and 2MASS catalogues for 11990 OB (2008AstL...34....7G; 2012AstL...38..694G) and 30671 K-type red giant branch stars (2011AstL...37..707G) is used to detect systematic large-scale variations of the interstellar extinction law within the nearest kiloparsec. The characteristic of the extinction law, the total-to-selective extinction ratio Rv, which also characterizes the size and other properties of interstellar dust grains, has been calculated for various regions of space by the extinction law extrapolation method. The results for the two classes of stars agree: the standard deviation of the "red giants minus OB" Rv differences within 500pc of the Sun is 0.2. The detected Rv variations between 2.2 and 4.4 not only manifest themselves in individual clouds but also span the entire space near the Sun, following Galactic structures. In the Local Bubble within about 100 pc of the Sun, Rv has a minimum. In the inner part of the Gould Belt and at high Galactic latitudes, at a distance of about 150 pc from the Sun, Rv reaches a maximum and then decreases to its minimum in the outer part of the Belt and other directions at a distance of about 500 pc from the Sun, returning to its mean values far from the Sun. The detected maximum of Rv at high Galactic latitudes is important when allowance is made for the interstellar extinction toward extragalactic objects. In addition, a monotonic increase in Rv by 0.3 per kpc toward the Galactic center has been found near the Galactic equator. It is consistent with the result obtained by Zasowski et al. (2009ApJ...707..510Z) for much of the Galaxy. Ignoring the Rv variations and traditionally using a single value for the entire space must lead to systematic errors in the calculated distances reaching 10%.2012PAZh...38...15Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/PAZh/38/15CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/239 : The Hipparcos and Tycho Catalogues (ESA 1997)I/259 : The Tycho-2 Catalogue (Hog+ 2000)I/311 : Hipparcos, the new Reduction of the Raw data (van Leeuwen 2007)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/PAZh/36/615 : 3D reddening map for stars from 2MASS phot. (Gontcharov, 2010)J/PAZh/38/776 : Complete sample of OB stars within 350pc (Gontcharov, 2012)J/PAZh/38/108 : 3D interstellar extinction map within nearest kpchttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/PAZh/38/15https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/PAZh/38/15http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/PAZh/38/15https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/PAZh/38/15https://vizier.iucaa.in/viz-bin/votable?-source=J/PAZh/38/15http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/PAZh/38/15GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/PAZh/38/15/mapxyzrRv tabulated as a function of X, Y, Z coordinatesRvTotal-to-selective extinction ratio (2)phys.absorption.gal;arith.ratiofloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintX[-650,650] X rectangular galactic coordinate (1)pcpos.cartesian.x;pos.galacticintY[-650,650] Y rectangular galactic coordinate (1)pcpos.cartesian.y;pos.galacticintZ[-600,600] Z rectangular galactic coordinate (1)pcpos.cartesian.z;pos.galacticint