J/A+A/664/A175 Milky Way low mass young stars from Gaia EDR3 (Prisinzano+, 2022)
Low-mass young stars in the Milky Way unveiled by DBSCAN and Gaia EDR3.
Mapping the star forming regions within 1.5 Kpc.
Prisinzano L., Damiani F., Sciortino S., Flaccomio E., Guarcello M.G.,
Micela G., Tognelli E., Jeffries R.D., Alcala J.M.
<Astron. Astrophys. 664, A175 (2022)>
=2022A&A...664A.175P 2022A&A...664A.175P (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Galactic plane ; Fundamental catalog ;
Clusters, open ; YSOs ; Stars, pre-main sequence
Keywords: methods: data analysis -
Galaxy: open clusters and associations: general - catalogs -
surveys - stars: formation - stars: pre-main sequence
Abstract:
With an unprecedented astrometric and photometric data precision, Gaia
EDR3 provides, for the first time, the opportunity to systematically
detect and map, in the optical bands, the low-mass populations of the
star forming regions (SFRs) in the Milky Way.
We aim to provide a catalogue of the Gaia EDR3 data (photometry,
proper motions and parallaxes) of the young stellar objects (YSOs)
identified in the Galactic plane |b|<30°) within about 1.5kpc. The
catalogue of the SFRs to which they belong is also provided to study
the properties of the very young clusters and put them in the context
of the Galaxy structure.
We applied the machine learning unsupervised clustering algorithm
density-based spatial clustering of applications with noise (DBSCAN)
to a sample of Gaia EDR3 data photometrically selected on the region
where very young stars (t≲10Myr) are expected to be found, with
the aim of identifying co-moving and spatially consistent stellar
clusters. A sub-sample of 52 clusters, selected among the 7323 found
with DBSCAN, has been used as template data set to identify very young
clusters from the pattern of the observed colour-absolute magnitude
diagrams through a pattern-match process.
We find 124440 candidate YSOs clustered in 354 SFRs and stellar
clusters younger than 10Myr and within ≲1.5kpc. In addition, 65 863
low-mass members of 322 stellar clusters located within ∼500pc and
with ages 10Myr≲t≲100Myr were also found.
The selected YSOs are spatially correlated with the well-known SFRs.
Most of them are associated with well-concentrated regions or complex
structures of the Galaxy, and a substantial number of them have been
recognised for the first time. The massive SFRs, such as, for example,
Orion, Sco-Cen, and Vela, located within 600-700 pc trace a very
complex three-dimensional pattern, while the farthest ones seem to
follow a more regular pattern along the Galactic plane.
Description:
Stars form in clusters and are mainly distributed in the Galactic
disk.
Mapping the youngest stellar populations of the Milky Way is crucial
to characterise the Galactic spiral arms and shed light on star and
planet formation theories. By combining the unprecedented astrometric
precision of Gaia EDR3 data, a machine learning unsupervised
clustering algorithm, and the stellar evolutionary properties from the
exquisite Gaia color-absolute magnitude diagrams, we identified 124440
young low mass stars clustered in 354 star forming regions (SFRs)
younger than 10Myr within about 1.5Kpc. In addition, 65863 low mass
members of 322 open clusters (OCs) located within about 500pc and
with ages 10Myr<t<100Myr were also found.
A substantial number of them are recognised for the first time and the
bulk of previously known star forming regions are also detected
enabling us to homogeneously single out the asymmetric complex
structure of the Galaxy in the solar neighbourhood.
The catalogue can serve as base for future studies on star formation
history, cluster dynamics, and Initial Mass Function, as well as
detailed studied of circumstellar disk evolution and search for young
giant planets by direct imaging.
Gaia EDR3 astrometric and kinematic parameters (l, b, parallaxes and
proper motions) and photometry in three broad bands (G, GBP, GRP)
in the Galactic Plane (b|<30deg) were used to select, with the machine
learning clustering algorithm DBSCAN, clusters kinematically and
spatially coherent. A subsample of 52 clusters, selected among the
7323 found with DBSCAN, has been used as template data set, to
identify very young clusters from the pattern of the observed
colour-absolute magnitude diagrams through a pattern match process.
Table 3 presents some properties of the SFRs and the OCs found in this
work. It includes an identification number, the median of the Galactic
coordinates of the members, the radius containing half of the members,
the cluster distance obtained as the median of inverted parallaxes of
members and the total number of members. A flag from 1 to 28 is
assigned to the SFRs with ages t<10Myr and from 29 to 36 to the OCs
with ages 10Myr<t<100Myr. The literature cluster names given in the
last column are mainly taken from Cantat-Gaudin & Anders
(2020A&A...633A..99C 2020A&A...633A..99C, Cat. J/A+A/633/A99) or Zucker et al.
(2020A&A...633A..51Z 2020A&A...633A..51Z, Cat. J/A+A/633/A51) or from Simbad, and are only
indicative of the region.
Table 4 lists the Gaia EDR3 data (source identification, Galactic
coordinates, parallax, proper motion and G, BP, RP magnitudes) of
members found for the SFRs and the OCs presented in Table 3. The flag
and the identification number of the cluster to which they belong are
also given.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 73 676 Properties of the SFRs and the OCs found
in this work
table4.dat 113 190303 Gaia EDR3 data of members found for the SFRs and
the OCs presented in Table 3
--------------------------------------------------------------------------------
See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/A+A/649/A3 : Gaia Early Data Release 3 photometric passbands (Riello+, 2021)
J/A+A/633/A51 : Distances to molecular clouds in SFR (Zucker+, 2020)
J/A+A/633/A99 : Gaia DR2 open clusters in the Milky Way. II
(Cantat-Gaudin+, 2020)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 5 I3 --- Cluster [1/676] ID of SFRs and young stellar clusters
7- 14 F8.3 deg GLON [] Median Galactic longitude of members
17- 23 F7.3 deg GLAT Median Galactic latitude of members
27- 32 F6.3 deg r50 Radius containing half of the members (r50)
37- 40 I4 pc d Median of inverted parallaxes of members
44- 48 I5 --- N Number of members
53- 54 I2 --- Flag [1/36] Flag ([1:28] for SFRs; [29:36] for OCs)
58- 73 A16 --- Name Literature cluster name
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaEDR3 Gaia EDR3 unique source identifier
21- 27 F7.3 deg GLON Galactic longitude
29- 35 F7.3 deg GLAT Galactic latitude
38- 43 F6.3 mas Plx Corrected parallax
47- 51 F5.3 mas e_Plx Standard error of parallax
53- 59 F7.3 mas/yr pmRA Proper motion in RA direction
63- 67 F5.3 mas/yr e_pmRA Standard error of proper motion in RA
69- 75 F7.3 mas/yr pmDE Proper motion in Dec
79- 83 F5.3 mas/yr e_pmDE Standard error of proper motion in Dec
86- 90 F5.2 mag Gmag G-band mean magnitude
93- 97 F5.2 mag BPmag ? Integrated BP mean magnitude
100-104 F5.2 mag RPmag Integrated RP mean magnitude
106-107 I2 --- Flag [1/36] Flag ([1:28] for SFRs; [29:36] for OCs)
111-113 I3 --- Cluster [1/676] Cluster ID (as in table 3)
--------------------------------------------------------------------------------
Acknowledgements:
Loredana Prisinzano, loredana.prisinzano(at)inaf.it
References:
Gaia Early Data Release 3: Summary of the contents and survey properties
Brown, A.G.A., et al., 2020A&A...649A...1G 2020A&A...649A...1G
Gaia Early Data Release 3: The astrometric solution
Lindegren, L., et al., 2020A&A...649A...2L 2020A&A...649A...2L
Gaia Early Data Release 3: Photometric content and validation
Riello, M., et al., 2020A+&...649A...3R 2020A+&...649A...3R, Cat. J/A+A/649/A3
Gaia Early Data Release 3: Parallax bias versus magnitude, colour and position
Lindegren, L., et al., 2020A&A...649A...4L 2020A&A...649A...4L
(End) Patricia Vannier [CDS] 06-Jun-2022