J/MNRAS/495/2882 Open cluster radii from Gaia proper motions (Sanchez+, 2020)
A catalogue of open cluster radii determined from Gaia proper motions.
Sanchez N., Alfaro E., Lopez-Martinez F.
<Mon. Not. R. Astron. Soc. 495, 2882-2893 (2020)>
=2020MNRAS.495.2882S 2020MNRAS.495.2882S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Proper motions
Keywords: methods: data analysis - catalogues - proper motions -
stars: kinematics and dynamics -
open clusters and associations: general
Abstract:
In this work, we improve a previously published method to calculate in
a reliable way the radius of an open cluster (OC). The method is based
on the behaviour of stars in the proper motion space as the sampling
changes in the position space. Here, we describe the new version of
the method and show its performance and robustness. Additionally, we
apply it to a large number of OCs using data from Gaia second data
release to generate a catalogue of 401 clusters with reliable radius
estimations. The range of obtained apparent radii goes from
Rc=1.4±0.1arcmin (for the cluster FSR 1651) to Rc=25.5±3.5arcmin
(for NGC 2437). Cluster linear sizes follow very closely a lognormal
distribution with a mean characteristic radius of Rc=3.7pc, and its
high radius tail can be fitted by a power law as
N∝Rc-3.11±0.35. Additionally, we find that number of
members, cluster radius, and age follow the relationship
Nc∝Rc1.2±0.1.Tc-1.9±0.4 where the younger and more
extensive the cluster, the more members it presents. The proposed
method is not sensitive to low density or irregular spatial
distributions of stars and, therefore, is a good alternative or
complementary procedure to calculate OC radii not having previous
information on star memberships.
Description:
We improved a method to calculate open cluster radii from proper
motion data in a reliable way. We applied it to a list of clusters
using data from Gaia DR2. This table contains the obtained radii for
401 clusters. Additionally, we report the estimated number of members
and the mean cluster proper motion.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 69 401 Catalog of open cluster radii
--------------------------------------------------------------------------------
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Cluster name
19- 27 F9.5 deg RAdeg Right ascension (J2000)
29- 37 F9.5 deg DEdeg Declination (J2000)
39- 43 F5.2 arcmin Rc Angular cluster radius
45- 48 F4.2 arcmin e_Rc Uncertainty in Rc
50 A1 --- Type [AB] Flag indicating type of solution
52- 55 I4 --- Nm Estimated number of kinematic members
57- 62 F6.3 mas/yr pmRA* Proper motion in right ascension, pmRA*cosDE
64- 69 F6.3 mas/yr pmDE Proper motion in declination
--------------------------------------------------------------------------------
Acknowledgements:
Nestor Sanchez, nestor.sanchezd(at)campusviu.es
(End) Nestor Sanchez [VIU, Spain], Patricia Vannier [CDS] 31-May-2020