J/A+A/620/A172      Solar neighbourhood young stars 3D mapping     (Zari+, 2018)

3D mapping of young stars in the solar neighbourhood with Gaia DR2. Zari E., Hashemi H., Brown A.G.A., K.Jardine, de Zeeuw P.T. <Astron. Astrophys. 620, A172 (2018)> =2018A&A...620A.172Z 2018A&A...620A.172Z (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Clusters, open ; Stars, nearby ; YSOs Keywords: stars: distances - stars: formation - stars: pre-main sequence - stars: early-type - solar neighbourhood - open clusters and associations Abstract: We study the three dimensional arrangement of young stars in the solar neighbourhood using the second release of the Gaia mission (Gaia DR2) and we provide a new, original view of the spatial configuration of the star forming regions within 500pc from the Sun. By smoothing the star distribution through a gaussian filter, we construct three dimensional density maps for early-type stars (upper-main sequence, UMS) and pre-main sequence (PMS) sources. The PMS and the UMS samples are selected through a combination of photometric and astrometric criteria. A side product of the analysis is a three dimensional, G-band extinction map, which we use to correct our colour-magnitude diagram for extinction and reddening. Both density maps show three prominent structures, Scorpius-Centaurus, Orion, and Vela. The PMS map shows a plethora of lower mass star forming regions, such as Taurus, Perseus, Cepheus, Cassiopeia and Lacerta, which are less visible in the UMS map, due to the lack of large numbers of bright, early-type stars. We report the finding of a candidate new open cluster towards l, b ∼218.5°, -2°, which could be related to the Orion star forming complex. We estimate ages for the PMS sample and we study the distribution of PMS stars as a function of their age. We find that younger stars cluster in dense, compact clumps, and are surrounded by older sources, whose distribution is instead more diffuse. The youngest groups that we find are mainly located in Scorpius-Centaurus, Orion, Vela and Taurus. Cepheus, Cassiopeia, and Lacerta are instead more evolved and less numerous. Finally, we find that the three dimensional density maps show no evidence for the existence of the ring-like structure which is usually referred to as the Gould Belt. Description: The files ums.dat (ums.fits) and ums.dat (pms.fits) contain the upper main sequence (UMS) and pre-main sequence (PMS) table data used in this work. We provide two additional files - pmsvt2.dat (pms_vt2.fits) and pmsvt3.dat )pms_vt3.fits) - which were not used in this study, but contain PMS stars within the S=2 and S=3 levels defined in the text. Finally we provide the extinction and colour excess data cubes that were produced to correct the colour-magnitude diagrams. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file pms.dat 199 43719 Pre-main sequence table data ums.dat 192 86102 Upper main sequence table data pmsvt2.dat 199 33985 Pre-main sequence stars within the S=2 level in tangential velocity pmsvt3.dat 199 23686 Pre-main sequence stars within the S=3 level in tangential velocity list.dat 212 2 List of fits maps fits/* . 6 Fits maps and tables -------------------------------------------------------------------------------- See also: I/337 : Gaia DR1 (Gaia Collaboration, 2016) I/345 : Gaia DR2 (Gaia Collaboration, 2018) Byte-by-byte Description of file: pms*.dat ums.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 I19 --- Source Unique source identifier (unique within a single release) (source_id) 21- 35 F15.11 deg GLON Galactic longitude (l) 37- 51 F15.11 deg GLAT Galactic latitude (b) 53- 62 F10.4 mag Plx Parallax (parallax) 64- 69 F6.4 mag e_Plx Standard error of parallax (parallax_error) 71- 79 F9.3 mas/yr pmGLON proper motion in galactic longitude, pmGLON*cosGLAT (pmlcosb) 81- 85 F5.3 mas/yr e_pmGLON Standard error of proper motion in galactic longitude (pmlerror) 87- 95 F9.3 mas/yr pmGLAT Proper motion in galactic latitude (pm_b) 97-101 F5.3 mas/yr e_pmGLAT Standard error of proper motion in galactic latitude (pmberror) 103-109 F7.4 --- pmlbcorr Correlation between proper motion in galactic longitude and proper motion in galactic latitude (pmlpmbcorr) 111-118 F8.3 km/s RV ?=- radial velocity (radial_velocity) 120-125 F6.3 km/s e_RV ?=- radial velocity error (radialvelocityerror) 127-134 F8.5 mag Gmag G-band mean magnitude (photgmean_mag) 136-143 F8.5 mag BPmag BP band mean magnitude (photbpmean_mag) 145-152 F8.5 mag RPmag RP band mean magnitude (photrpmean_mag) 154-160 F7.5 --- E(BR/RP) BP/RP excess factor (photbprpexcessfactor) 162-173 E12.6 --- chi2AL AL chi-square value (astrometricchi2al) 175-178 I4 --- NgAL Number of good observation AL (astrometricngoodobsal) 180-185 F6.4 mag AG Extinction in G-band (A_G) 187-192 F6.4 mag E(BP-RP) Colour excess in BP-RP (E_BPminRP) 194-199 F6.4 --- UWE ? Unit Weight Error, as defined in Lindegren et al., 2018A&A...616A...2L 2018A&A...616A...2L, Cat. I.345), only in pms.,dat file (UWE) -------------------------------------------------------------------------------- Byte-by-byte Description of file: list.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Nx Number of pixels along X-axis 5- 7 I3 --- Ny Number of pixels along Y-axis 9- 11 I3 --- Nz Number of slices 13- 16 I4 Kibyte size Size of FITS file 18- 32 A15 --- FileName Name of FITS file, in subdirectory fits 34-212 A179 --- Title Title of the FITS file -------------------------------------------------------------------------------- Acknowledgements: Eleonora Zari, zariem(at)strw.leidenuniv.nl Referneces: Gaia Collaboration, Prusti et al., 2016A&A...595A...1G 2016A&A...595A...1G Gaia Collaboration, Brown et al., 2016A&A...595A...2G 2016A&A...595A...2G
(End) Patricia Vannier [CDS] 24-Oct-2018
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