J/A+A/698/A168ivo://CDS.VizieR/J/A+A/698/A168doi:10.26093/cds/vizier/bc-nt/lbgiCDSMandarakas N.Tassis K.Skalidis R.2026-08-03T06:54:55Z2025-06-12T08:49:43ZCDS support team

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

cds-question@unistra.frstellar-distanceThe Serkowski relation is the cornerstone of studies of starlight polarizations as a function of wavelength. Although empirical, its extensive use since its inception in 1975 to describe polarization induced by interstellar dust has elevated the relation to the status of an indisputable "law": this is the benchmark against which models of interstellar dust grains are validated. We revisit the effects of the three - dimensional structure of the interstellar medium (ISM) on the wavelength dependence of interstellar polarization. We use analytical models to show how the wavelength dependence of both the polarization fraction and direction is affected by the presence of multiple clouds along the line of sight (LOS). We account for recent developments in dust distribution modelling and we utilize an expanded archive of stellar polarization measurements to establish the effect of multiple clouds along the LOS. We highlight concrete examples of stars whose polarization profiles are severely affected by LOS variations of the dust grain and magnetic field properties, and we provide a recipe to accurately fit multiple cloud Serkowski models to such cases. We present, for the first time, compelling observational evidence that the three - dimensional structure of the magnetized ISM often results to the violation of the Serkowski relation. We show that three - dimensional effects impact interstellar cloud parameters derived from Serkowski fits. In particular, the dust size distribution in single - cloud sightlines may differ from analyses that ignore 3D effects, with important implications for dust modelling in the Galaxy. Our results suggest that multiwavelength stellar polarization measurements offer an independent probe of the LOS variations of the magnetic field orientation, and thus constitute a potentially valuable new tool for the 3D cartography of the interstellar medium. Finally, we caution that, unless 3D effects are explicitly accounted for, a poor fit to the Serkowski relation does not, by itself, constitute conclusive evidence that a star is intrinsically polarized.2025A&A...698A.168Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/698/A168CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/698/A168https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/698/A168http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/698/A168https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/698/A168https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/698/A168http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/698/A168GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/698/A168/table4 (Information about the statistical sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/698/A168/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/698/A168/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/698/A168/table4?GETtext/xml+votable180.050000true80.6805633.288090.0055555555555555566/1285 1287 2859 2945 2948 3031 3384 3634-3635 3755 14353 21633 21635 23977 28890-28892 30635 31239-31240 31245 31250 31256 36956-36957 36959 37122 37128-37129 37846 42436https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/698/A168?format=asciidefaultJ/A+A/698/A168/table4Information about the statistical samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia DR3 source_idmeta.id;meta.mainRA_ICRSRight Ascension (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at Ep=2016.0degpos.eq.dec;meta.mainDistanceDistance of the sourcepcpos.distanceintAvExtinction of the sourcemagphys.absorptionfloatNbandsNumber of bands with measurementsmeta.numberintNCNumber of identified cloudsmeta.numbercharchi2nuchi2_nu for the q-u fittingstat.fit.chi2floatPmaxP_max_ retrieved from q-u fitting%phys.polarizationfloatKK retrieved from q-u fittingstat.fit.paramfloatlambdamaxlambda_max_ retrieved from q-u fittingumem.wlfloatthetatheta retrieved from q-u fittingdegstat.fit.paramfloat