J/A+A/609/A8ivo://CDS.VizieR/J/A+A/609/A8doi:10.26093/cds/vizier.36090008CDSBailer-Jones C.A.L.2018-01-23T06:57:53Z2017-12-22T19:27:39ZCDS support team

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

cds-question@unistra.frastrometrysolar-systemI report on close encounters of stars to the Sun found in the first Gaia data release (GDR1). Combining Gaia astrometry with radial velocities of around 320 000 stars drawn from various catalogues, I integrate orbits in a Galactic potential to identify those stars which pass within a few parsecs. Such encounters could influence the solar system, for example through gravitational perturbations of the Oort cloud. 16 stars are found to come within 2pc (although a few of these have dubious data). This is fewer than were found in a similar study based on Hipparcos data, even though the present study has many more candidates. This is partly because I reject stars with large radial velocity uncertainties (>10km/s), and partly because of missing stars in GDR1 (especially at the bright end). The closest encounter found is Gl 710, a K dwarf long-known to come close to the Sun in about 1.3Myr. The Gaia astrometry predict a much closer passage than pre-Gaia estimates, however: just 16000AU (90% confidence interval: 10000-21000AU), which will bring this star well within the Oort cloud. Using a simple model for the spatial, velocity, and luminosity distributions of stars, together with an approximation of the observational selection function, I model the incompleteness of this Gaia-based search as a function of the time and distance of closest approach. Applying this to a subset of the observed encounters (excluding duplicates and stars with implausibly large velocities), I estimate the rate of stellar encounters within 5pc averaged over the past and future 5Myr to be 545+/-59Myr^-1^. Assuming a quadratic scaling of the rate within some encounter distance (which my model predicts), this corresponds to 87+/-9Myr-1 within 2pc. A more accurate analysis and assessment will be possible with future Gaia data releases.2018A&A...609A...8Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/609/A8CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/239 : The Hipparcos and Tycho Catalogues (ESA 1997)I/259 : The Tycho-2 Catalogue (Hog+ 2000)I/337 : Gaia DR1 (Gaia Collaboration, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/609/A8https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/609/A8http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/609/A8https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/609/A8https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/609/A8http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/609/A8GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/609/A8/encount (Perihelion parameters for all objects with a median perihelion distance below 10pc, in order of increasing median perihelion distance (table3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/609/A8/encount?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/609/A8/encount?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/609/A8/encount?GETtext/xml+votable180.050000true274.9618383-1.93861190.0055555555555555566/259 377 497 861 1030 1033 1077 1212 1237 1247 1289 1310 1408 1606 1822 1834 1888 1938 1976 2149 3085 3616 3929 3979 4808 4920 5065 5095 5263 6217 6346 6429 6447 7003 7076 7129 7419 7612 7698 7736 7763 7765 8011 8210 8887 9093 9339 9436 9529 9679 9801 9994 10023 10149 10448 10457 10683 10735 10812 10915 11010 11633 11671 11732 12015 12340 12388 12512 12621 12713 13203 13214 13954 14036 14277 14424 14539 14641 14709 14735 14765 14784 14791 14850 15030 15044 15121 15126 15145 15960 16144 16932 17020 17177 17458 17698 18299 18618 18821 18929 19064 19488 19997 20072 20113 20494 20566 20683 20701 20745 20760 20778 20808 20810 20864 21047 21050 21076 21080 21151 21179 21208 21228 21276 21386 21469 21477 21484 21673 21726 21784 21808 21838 21953 22020 22046 22128 22175 22185 22238 22250 22277 22490 22740 22744 22746 22808 22810 22849 22882 23056 23093 23555 23634 23719 23731 23765 23767 23938 23958 24117 24213 24502 24514 24713 24722 24841 25516 25709 26122 26163 26379 26538 27144 27374 27844 28341 28510 28518 28646 28822 29084 29093 29144 29152 29158 29289 29374 29578 29640 29661 29756 29777 29827 30176 30230 30255 30286 30343 30345 30451 30464 30599 30626 30658 30859 30921 30939 31029 31133 31191 31264 31267 31308 31415 31650 31730 31935 31970 31998 32115 32293 32396 32458 32500 32549 32579 32622 32847 32875 33075 33101 33116 33120 33156 33185 33206 33210 33398 33418 33510 33705 33937 34004 34074 34115 34119 34123 34144 34167 34175 34208 34245 34481 34499 34533 34541 34581 34591 34680 34793 34896 34905 35170 35288 35330 35626 35699 35934 36037 36208 36249 36288 36342 36418 36608 36631 36726 36915 36961 36965 37000 37134 37382 37414 37479 37626 37680 37685 37797 37809 37842 38055 38243 38414 38598 38807 38865 38868 38950 39036 39101 39212 39284 39342 39457 39464 39500 39502 39520 39554 39587 39766 39851 39869 39888 39912 40189 40197 40242 40664 40712 40716 40811 40972 40975 40981 41021 41326 41463 41607 41679 42022 42070 42189 42228 42333 42420 42426 42433 42520 42595 42778 43247 43258 43505 43795 43851 43884 44235 44715 44904 44937 45186 45237 45364 45373 45377 45423 45449 45483 45504 45506 45542 45575 45621-45622 45631 45680 45683 45823 45878 45985 45992 46020 46118 46287 46289 46655 46741 47188 47214 47442 47795 47961 48129 48258 48361 48572 48623 48744 48959https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/609/A8?format=asciidefaultJ/A+A/609/A8/encountPerihelion parameters for all objects with a median perihelion distance below 10pc, in order of increasing median perihelion distance (table3)SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDTycho or Hipparcos identifiermeta.idcharCat[1/10] Radial velocity catalogue identifier (1)meta.id;spect.dopplerVeloc;meta.tableinttphmedMedian perihelion timekyrsrc.orbital.periastron;stat.mediandoubletphlo5% bound on perihelion time distributionkyrsrc.orbital.periastrondoubletphup95% bound on perihelion time distributionkyrsrc.orbital.periastrondoubledphmedMedian perihelion distancepcpos.distance;src.orbital.periastron;stat.medianfloatdphlo5% bound on perihelion distance distributionpcpos.distance;src.orbital.periastronfloatdphup95% bound on perihelion distance distributionpcpos.distance;src.orbital.periastronfloatvphmedMedian perihelion speedkm/sphys.velocdoublevphlo5% bound on perihelion speed distributionkm/sphys.velocdoublevphup95% bound on perihelion speed distributionkm/sphys.velocdoublef0.5Probability star approaches within 0.5pcstat.fit.goodnessintf1.0Probability star approaches within 1.0pcstat.fit.goodnessintf2.0Probability star approaches within 2.0pcstat.fit.goodnessintplxParallaxmaspos.parallax.trigdoublee_plxParallax uncertainty (1 sigma)masstat.error;pos.parallaxdoublepmProper motionmas/yrpos.pmdoublee_pmProper motion uncertainty (1 sigma)mas/yrstat.errordoubleRVRadial velocitykm/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertainty (1 sigma)km/sstat.errordoubleGaiaDisplay the Gaia TGAS data (Gaia Collaboration, 2016, Cat. I/337)meta.ref.urlchar_RAPositions from Simnad and Tycho 2 (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simnad and Tycho 2 (declination part)degpos.eq.dec;meta.main