2017A&A...608A.148Z


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.28CET09:35:28

2017A&A...608A.148Z - Astronomy and Astrophysics, volume 608A, 148-148 (2017/12-1)

Mapping young stellar populations toward Orion with Gaia DR1.

ZARI E., BROWN A.G.A., DE BRUIJNE J., MANARA C.F. and DE ZEEUW P.T.

Abstract (from CDS):

In this work we use the first data release of the Gaia mission to explore the three-dimensional arrangement and age ordering of the many stellar groups toward the Orion OB association, aiming at a new classification and characterization of the stellar population not embedded in the Orion A and B molecular clouds. We make use of the parallaxes and proper motions provided in the Tycho Gaia Astrometric Solution (TGAS) subset of the Gaia Data Release 1 (DR1) catalog and of the combination of Gaia DR1 and 2MASS photometry. In TGAS, we find evidence for the presence of a young population at a parallax p∼2.65mas, which is loosely distributed around the following known clusters: 25 Ori, ε Ori, and σ Ori, and NGC 1980 (ι Ori) and the Orion Nebula Cluster (ONC). The low mass counterpart of this population is visible in the color magnitude diagrams constructed by combining Gaia DR1 G-band photometry and 2MASS. We study the density distribution of the young sources in the sky using a kernel density estimation (KDE). We find the same groups as in TGAS and also some other density enhancements that might be related to the recently discovered Orion X group, Orion dust ring, and λ Ori complex. The maps also suggest that the 25 Ori group presents a northern elongation. We estimated the ages of this population using a Bayesian isochronal fitting procedure assuming a unique parallax value for all the sources, and we inferred the presence of an age gradient going from 25 Ori (13-15Myr) to the ONC (1-2Myr). We confirmed this age ordering by repeating the Bayesian fit using the Pan-STARRS1 data. Intriguingly, the estimated ages toward the NGC 1980 cluster span a broad range of values. This can either be due to the presence of two populations coming from two different episodes of star formation or to a large spread along the line of sight of the same population. Some confusion might arise from the presence of unresolved binaries, which are not modeled in the fit, and usually mimic a younger population. Finally, we provisionally relate the stellar groups to the gas and dust features in Orion. Our results form the first step toward using Gaia data to unravel the complex star formation history of the Orion region in terms of the various star formation episodes, their duration, and their effects on the surrounding interstellar medium.

Abstract Copyright: © ESO, 2017

Journal keyword(s): stars: distances - stars: formation - stars: pre-main sequence - stars: early-type - stars: early-type

VizieR on-line data: <Available at CDS (J/A+A/608/A148): origaia.dat x2mass.dat oritgas.dat fits/*>

Status in Simbad:  will not be processed

Simbad objects: 29

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Number of rows : 29

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Eridanus Shell sh 02 17 31 +07 49.6           ~ 45 0
2 NAME Orion X As* 05 14 -01.           ~ 4 0
3 LDN 1588 MoC 05 20.8 +08 30           ~ 17 0
4 NAME 25 Ori Group OpC 05 24 36 +01 48.0           ~ 87 1
5 NAME Barnard's Loop HII 05 27.5 -03 58           ~ 102 1
6 Barnard 30 DNe 05 30.3 +12 46           ~ 39 0
7 Ass Ori OB 1b As* 05 34.0 -01 30           ~ 234 0
8 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 1932 1
9 Cl Collinder 69 OpC 05 35 06 +09 56.0     2.8     ~ 221 0
10 NGC 1981 OpC 05 35 09 -04 25.9     4.2     ~ 69 0
11 NGC 1977 SFR 05 35 16.0 -04 49 15           ~ 181 0
12 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1445 1
13 M 42 HII 05 35 17.3 -05 23 28           ~ 3687 0
14 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 470 0
15 NAME Ori Complex Cld 05 35.3 -05 23           ~ 324 0
16 Ass Ori OB 1c As* 05 35 21 -05 20.5           ~ 129 1
17 NGC 1980 OpC 05 35 24 -05 54.9     2.5     ~ 83 0
18 M 43 HII 05 35 31 -05 16.2           ~ 156 0
19 NAME Ori I As* 05 38 -02.8           ~ 550 0
20 NAME Ori A MoC 05 38 -07.1           ~ 2639 0
21 NAME sigma Orionis Cluster MGr 05 38 42 -02 36.0           ~ 478 0
22 LDN 1641 MoC 05 39.0 -07 00           ~ 421 0
23 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1142 0
24 NGC 2112 OpC 05 53 45 +00 24.6     9.1     ~ 65 0
25 NAME ORI MOL CLOUD MoC 05 56 -01.8           ~ 831 1
26 NAME Mon R2 HII 06 07 46.6 -06 22 59           ~ 643 2
27 Ass Ori OB 1a As* ~ ~           ~ 190 0
28 NAME eps Ori Cluster Cl* ~ ~           ~ 19 1
29 NAME Gould Belt PoG ~ ~           ~ 700 1

    Equat.    Gal    SGal    Ecl

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2020.02.28-09:35:28

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