J/MNRAS/511/4500ivo://CDS.VizieR/J/MNRAS/511/4500doi:10.26093/cds/vizier.75114500CDSYep A.C.White R.J.2024-08-22T20:15:15Z2022-12-30T09:58:24ZCDS support team

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

cds-question@unistra.frmilky-way-galaxystellar-associationsphotometryvisible-astronomystellar-distancestellar-massesBased on Gaia DR2 data and new CHIRON radial velocities, we have discovered that two nearby stellar associations UPK 535 (318.08+/-0.29pc, 25^+15^_-10_Myr, 174 stars) and Yep 3 (339.54+/-0.25pc, 45^+55^_-20_Myr, 297 stars) in the Gum Nebula have recently collided. We project stars' current positions, motions, and measurement uncertainties backward and forward through time in a 10000-trial Monte Carlo simulation. On average, the associations' centres of mass come within 18.89+/-0.73pc of each other 0.84+/-0.03Myr ago. A mode of 54+/-7 close (<1pc) stellar encounters occur during the collision. We cannot predict specific star-star close encounters with our current ~7.6pc distance precision and 21.5-per-cent-complete radial velocity sample. Never the less, we find that two stars in UPK 535 and two stars in Yep 3 undergo a nonspecific close encounter in >70 per cent of trials and multiple close encounters in ~30 per cent. On average, the closest approach of any two stars is 0.13+/-0.06pc, or 27000+/-12000au. With impulse-tracing values up to 2.7^+3.1^_-1.1_(M_{sun}_/pc^2^)/(km/s) , such close encounters could perturb stars' Oort cloud comets (if present), cause heavy bombardment events for exoplanets (if present), and reshape solar system architectures. Finally, an expansion of our simulation suggests other associations in the region are also interacting. Association collisions may be commonplace, at least in the Gum Nebula straddling the Galactic plane, and may spur solar system evolution more than previously recognized.2022MNRAS.511.4500Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/511/4500CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)Table 1: Position and motion cuts for isolating the associations UPK 535 andhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/511/4500https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/511/4500http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/511/4500https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/511/4500https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/511/4500http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/511/4500GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/511/4500/table3a (UPK 535)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/511/4500/table3a?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/511/4500/table3a?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/511/4500/table3a?GETtext/xml+votable180.050000true127.1059633270868-50.73807954187750.005555555555555556Cone search capability for table J/MNRAS/511/4500/table3b (Yep 3)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/511/4500/table3b?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/511/4500/table3b?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/511/4500/table3b?GETtext/xml+votable180.050000true132.612838292288-54.13164219310050.0055555555555555564/2363 5/9423 9445 9447 9796-9798 6/37686 37739 37777 37779 37785-37787 37799 37805-37807 37834 37856 378581.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/511/4500?format=asciiOpticaldefaultJ/MNRAS/511/4500/table3aUPK 535plxParallaxmaspos.parallax.trigfloate_Vmag? Error in V magnitudemagstat.error;phot.magdoublenullableSpType? Spectral typesrc.spTypechare_SpType? Class error in spectral typestat.error;src.spTypedoublenullableBinFlag? Spectroscopic binary star flagmeta.codecharDistDistance (3)pcpos.distancedoubleE_DistUncertainty (upper) on distance from parallax errorpcstat.error;stat.maxdoublee_DistUncertainty (lower) on distance from parallax errorpcstat.errordoubleMass? Stellar mass from spectral type or BP-RP color or corrected absolute G magnitudesolMassphys.massdoublenullablee_MassError in stellar masssolMassstat.error;phys.massdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 source ID (Caution, some wrong identifiers)meta.id;meta.mainNameName of spectroscopically observed starmeta.idcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_plxStandard error in parallaxmasstat.error;pos.parallaxfloatpmRAProper motion in right ascension (1)mas/yrpos.pm;pos.eq.rafloate_pmRAStandard error in proper motion in right ascension, pmRA*cosDEmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion in declination (2)mas/yrpos.pm;pos.eq.decfloate_pmDEStandard error in proper motion in declinationmas/yrstat.error;pos.pm;pos.eq.decfloatRV? Spectroscopic heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricdoublenullablee_RV? Error in radial velocitykm/sstat.errordoublenullableGmag? Gaia DR2 G-band mean magnitudemagphot.mag;em.optdoublenullablee_Gmag? Error in G magnitude from error in fluxmagstat.error;phot.magdoublenullableBPmag? Gaia DR2 integrated BP mean magnitudemagphot.mag;em.opt.Bdoublenullablee_BPmag? Error in BP magnitude from error in fluxmagstat.error;phot.magdoublenullableRPmag? Gaia DR2 integrated RP mean magnitudemagphot.mag;em.opt.Rdoublenullablee_RPmag? Error in RP magnitude from error in fluxmagstat.error;phot.magdoublenullableVmag? Johnson V magnitude from BP and RPmagphot.mag;em.opt.VdoublenullableJ/MNRAS/511/4500/table3bYep 3recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 source ID (Caution, some wrong identifiers)meta.id;meta.mainNameName of spectroscopically observed starmeta.idcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainplxParallaxmaspos.parallax.trigfloate_plxStandard error in parallaxmasstat.error;pos.parallaxfloatpmRAProper motion in right ascension (1)mas/yrpos.pm;pos.eq.rafloate_pmRAStandard error in proper motion in right ascension, pmRA*cosDEmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion in declination (2)mas/yrpos.pm;pos.eq.decfloate_pmDEStandard error in proper motion in declinationmas/yrstat.error;pos.pm;pos.eq.decfloatRV? Spectroscopic heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricdoublenullablee_RV? Error in radial velocitykm/sstat.errordoublenullableGmag? Gaia DR2 G-band mean magnitudemagphot.mag;em.optdoublenullableBPmag? Gaia DR2 integrated BP mean magnitudemagphot.mag;em.opt.Bdoublenullablee_BPmag? Error in BP magnitude from error in fluxmagstat.error;phot.magdoublenullableSpType? Spectral typesrc.spTypechare_Gmag? Error in G magnitude from error in fluxmagstat.error;phot.magdoublenullableRPmag? Gaia DR2 integrated RP mean magnitudemagphot.mag;em.opt.Rdoublenullablee_RPmag? Error in RP magnitude from error in fluxmagstat.error;phot.magdoublenullableVmag? Johnson V magnitude from BP and RPmagphot.mag;em.opt.Vdoublenullablee_Vmag? Error in V magnitudemagstat.error;phot.magdoublenullablee_SpType? Class error in spectral typestat.error;src.spTypedoublenullableBinFlag? Spectroscopic binary star flagmeta.codecharDistDistance (3)pcpos.distancedoubleE_DistUncertainty (upper) on distance from parallax errorpcstat.error;stat.maxdoublee_DistUncertainty (lower) on distance from parallax errorpcstat.errordoubleMass? Stellar mass from spectral type or BP-RP color or corrected absolute G magnitudesolMassphys.massdoublenullablee_MassError in stellar masssolMassstat.error;phys.massdouble