J/A+A/551/A53ivo://CDS.VizieR/J/A+A/551/A53doi:10.26093/cds/vizier.35510053CDSGuerrero M.A.Miranda L.F.Ramos-Larios G.Vazquez R.2016-07-28T14:37:01Z2013-03-04T09:37:25ZCDS support team

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

cds-question@unistra.frplanetary-nebulaeOnce classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has only recently been recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time lapse between the ejection of the two pairs of bipolar lobes is much shorter than their dynamical ages, implying a rapid change in the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as for type II PNe) and a high helium abundance (as for type I PNe), although not atypical among symbiotic stars. Such an anomalous chemical composition may have resulted from the curtailment of the time in the asymptotic giant branch by the evolution of the progenitor star through a common envelope phase.2013A&A...551A..53Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/551/A53CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/551/A53https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/551/A53http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/551/A53https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/551/A53https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/551/A53http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/551/A53GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/551/A53/list (List of fits files)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/551/A53/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/551/A53/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/551/A53/list?GETtext/xml+votable180.050000true320.8041738.973610.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/551/A536/13958 13964https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/551/A53?format=asciidefaultJ/A+A/551/A53/listList of fits filesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainScale? Scale of the imagearcsec/pixinstr.scalefloatnullableNxNumber of pixels along X-axispixmeta.numberintNy? Number of pixels along Y-axispixmeta.numberintnullableFileNameName of FITS file in subdirectory fitsmeta.id;meta.fitscharSpplot of spectrummeta.ref.urlcharFITSDownload the FITS filemeta.ref.urlcharTitleTitle of the filemeta.note