J/ApJ/917/21 Stellar kinematics in Orion Complex with Gaia (Swiggum+, 2021) ================================================================================ Evidence for radial expansion at the core of the Orion Complex with Gaia EDR3. Swiggum C., D'Onghia E., Alves J., Grossschedl J., Foley M., Zucker C., Meingast S., Chen B., Goodman A. =2021ApJ...917...21S ================================================================================ ADC_Keywords: Radial velocities; Proper motions; Star Forming Region; Stars, ages; Associations, stellar; Optical Keywords: Star forming regions ; Stellar feedback ; Stellar associations ; Stellar ages ; Stellar dynamics Abstract: We present a phase-space study of two stellar groups located at the core of the Orion Complex: Briceno-1 and Orion Belt Population-near (OBP-near). We identify the groups with the unsupervised clustering algorithm, Shared Nearest Neighbor (SNN), which previously identified 12 new stellar substructures in the Orion Complex. For each of the two groups, we derive the 3D space motions of individual stars using Gaia-EDR3 proper motions supplemented by radial velocities from Gaia-DR2, APOGEE-2, and GALAH DR3. We present evidence for radial expansion of the two groups from a common center. Unlike previous work, our study suggests that evidence of stellar group expansion is confined only to OBP-near and Briceno-1, whereas the rest of the groups in the complex show more complicated motions. Interestingly, the stars in the two groups lie at the center of a dust shell, as revealed via an extant 3D dust map. The exact mechanism that produces such coherent motions remains unclear, while the observed radial expansion and dust shell suggest that massive stellar feedback could have influenced the star formation history of these groups. Description: Chen+ (2020A&A...643A.114C) applied two clustering algorithms, namely, Shared Nearest Neighbor (SNN; Chen+ 2018ApJ...860...70C) and EnLink (Sharma & Johnston 2009ApJ...703.1061S), to Gaia DR2 in the vicinity of Orion, to uncover stellar groups clustered in R.A., decl., parallaxes and proper motions. We query the Gaia EDR3 database using the same region selection for Orion as used in Chen et al. (2020); see Section 2. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 112 15 Summary of Shared Nearest Neighbor (SNN) groups table2.dat 257 5020 Shared Nearest Neighbor (SNN) catalog -------------------------------------------------------------------------------- See also: I/345 : Gaia DR2 (Gaia Collaboration, 2018) I/350 : Gaia EDR3 (Gaia Collaboration, 2020) III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020) V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020) J/A+A/289/101 : Orion OB1 association. I. (Brown+, 1994) J/AJ/131/1574 : Infrared photometry of IC348 members (Lada+, 2006) J/ApJ/661/1119 : Spectroscopy in the 25 Ori group (Briceno+, 2007) J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009) J/MNRAS/424/1925 : Spectrocopic Binarity of O and B type stars (Chini+, 2012) J/A+A/584/A26 : Cosmography of OB stars in solar neighbourhood (Bouy+, 2015) J/AJ/153/188 : Spectroscopy of the foreground pop. in Orion A (Fang+, 2017) J/A+A/608/A148 : Stellar populations towards Orion with GaiaDR1 (Zari+, 2017) J/ApJS/236/27 : APOGEE-2 survey of Orion Complex (OSFC). I. (Cottle+, 2018) J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018) J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018) J/A+A/626/A17 : Young pop. in Vela-Puppis region (Cantat-Gaudin+, 2019) J/A+A/622/A149 : Vienna survey in Orion. III. (Grossschedl+, 2019) J/A+A/631/A166 : Members of 5 cluster in Ori OB1a association (Kos+, 2019) J/ApJ/870/32 : Kinematics in young star clusters & assoc. (Kuhn+, 2019) J/MNRAS/486/2477 : Catalogue of members of NGC 6530 (Wright+, 2019) J/ApJ/899/128 : Members of NGC7000/IC5070 Complex (Kuhn+, 2020) J/MNRAS/495/663 : Gaia DR2 OB associations (Ward+, 2020) J/A+A/633/A51 : Distances to molecular clouds in SFR (Zucker+, 2020) J/MNRAS/506/150 : The GALAH+ Survey DR3 (Buder+, 2021) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- Group [1/24] Original SNN group label assigned by Chen+ (2020A&A...643A.114C) 4- 21 A18 --- Name Name of the group 23- 25 I3 --- Stab [41/383] Stability score from SNN 27- 29 I3 --- Ns [85/909] Number of stars in group 31- 34 F4.1 Myr Age [3.1/22.5] Age of group 36- 38 F3.1 Myr e_Age [1.5/6.9] Lower uncertainty on Age 40- 42 F3.1 Myr E_Age [0.9/9.8] Upper uncertainty on Age 44- 46 F3.1 mag Av [0.2/0.6] Extinction of group 48- 51 F4.1 % DR2p [58/84.3] Percent of group's stars from Chen+ (2020A&A...643A.114C) that are coincident with present work's stellar membership 53- 56 F4.1 deg RAdeg [78.5/88] Average right ascension 58- 60 F3.1 deg e_RAdeg [0.4/1.5] RAdeg 1{sigma} uncertainty 62- 65 F4.1 deg DEdeg [-8.1/9.7] Average declination 67- 69 F3.1 deg e_DEdeg [0.6/2.2] DEdeg 1{sigma} uncertainty 71- 75 F5.1 pc Dist [285/446] Average distance 77- 80 F4.1 pc e_Dist [11/31] Dist 1{sigma} uncertainty 82- 85 F4.1 mas/yr pmRA [-3.3/2] Average pmRA 87- 89 F3.1 mas/yr e_pmRA [0.2/0.4] pmRA 1{sigma} uncertainty 91- 94 F4.1 mas/yr pmDE [-3/0.8] Average pmDE 96- 98 F3.1 mas/yr e_pmDE [0.2/0.3] pmDE 1{sigma} uncertainty 100- 103 F4.1 km/s HRV [14/33] Average heliocentric RV 105- 108 F4.1 km/s e_HRV [3/77] HRV 1{sigma} uncertainty 110- 112 I3 --- Nrv [2/197] Number of available RVs from Gaia DR2, APOGEE-2, and GALAH DR3 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- Group [1/24] Shared nearest neighbor (SNN) label (as in Table 1) 4- 22 I19 --- GaiaDR3 Gaia EDR3 source ID 24- 40 F17.14 deg RAdeg [75.18/89.88] Right Ascension, Gaia DR3 (ICRS) at Epoch=2016.0 42- 53 F12.10 deg e_RAdeg [0.007/1.11] Uncertainty in RAdeg 55- 74 F20.16 deg DEdeg [-14.3/13.1] Declination, Gaia DR3 (ICRS) at Epoch=2016.0 76- 87 F12.10 deg e_DEdeg [0.006/1.1] Uncertainty in DEdeg 89-106 F18.16 mas Plx [2/4.1] Parallax, Gaia DR3 108-119 F12.10 mas e_Plx [0.01/0.7] Uncertainty in Plx 121-142 F22.19 mas/yr pmRA [-3.84/2.5] Proper motion in RA, Gaia DR3 144-155 F12.10 mas/yr e_pmRA [0.01/1.1] Uncertainty in pmRA 157-178 F22.19 mas/yr pmDE [-3.5/1.5] Proper motion in DE, Gaia DR3 180-191 F12.10 mas/yr e_pmDE [0.008/1.1] Uncertainty in pmDE 193-203 F11.7 km/s RVel1 [-24.8/52.8]? Gaia DR2 radial velocity 205-215 F11.8 km/s e_RVel1 [0.27/20]? Uncertainty in RVel1 217-225 F9.5 km/s RVel2 [-22/633]? APOGEE-2 radial velocity 227-233 F7.5 km/s e_RVel2 [0.01/5.7]? Uncertainty in RVel2 235-243 F9.6 km/s RVel3 [3.6/91.3]? GALAH DR3 radial velocity 245-252 F8.6 km/s e_RVel3 [0.3/3]? Uncertainty in RVel3 254-257 F4.2 --- Prob [0.02/1] SNN probability -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Jan-2023