J/PASP/131/D4101 Likely Pleiades members with Gaia DR2 (Gao, 2019)
An investigation of the Pleiades cluster using machine learning.
Gao X.-H.
<PASP, 131d, 4101 (2019)>
=2019PASP..131d4101G 2019PASP..131d4101G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar
Keywords: (Galaxy:) open clusters and associations: individual (Pleiades) -
parallaxes - proper motions - methods: data analysis -
methods: statistical
Abstract:
This paper presents an investigation on fundamental astrophysical
properties of the Pleiades cluster (M 45) using high-precision
astrometric and photometric data from the Gaia Data Release 2
(Gaia-DR2). To obtain reliable cluster members, a machine-learning
(ML) method is used to compute membership probabilities for 31462
sample stars within a radius of 6.5° from the cluster center, both
the astrometric and photometric data are taken into account. We obtain
a total number of 1454 likely cluster members with membership
probabilities larger than 0.6, including a well-known white dwarf
(LB 1497) with a high membership probability of ∼0.96. We find a
well-defined relationship between the parallaxes and proper motions of
the cluster members, the most likely explanation for the relationship
is that the depth effect of the cluster along the line of sight must
be taken into consideration. Using Monte Carlo simulations, the most
likely distance, proper motion, and radial velocity of the cluster are
determined to be D=136.0±0.1pc, (<µαcosδ>,
<µδ>)=(+20.141±0.093, -45.536+/ -0.081)mas/yr, and
<Vr≥+5.8±0.1km/s, respectively. It is found that the likely
cluster members extend outward to a limiting radius of
Rlim=310'±12' (12.3±0.5pc) from the cluster center, and the
total mass of the cluster within this radius is
Mtot=721±93M☉. We find clear evidence for the presence of
spatial mass segregation in this young cluster by analyzing the
photometry and spatial positions of the likely cluster members.
Interestingly, we also find that four high-mass cluster members with
high membership probabilities (>0.99) are being ejected from the inner
region of the cluster, they may have formed via close encounters
between single and binary stars.
Description:
We reinvestigate likely cluster members and fundamental astrophysical
properties of the Pleiades cluster based on the high-precision
astrometry and photometry from Gaia-DR2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 56 1454 A catalog of fundamental information for the
1454 likely cluster members with PRF≥0.6
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See also:
J/A+A/563/A45 : Pleiades cluster membership probabilities (Sarro+, 2014)
J/A+A/617/A15 : Membership probabilities of Pleiades objects (Olivares+, 2018)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 18 I18 --- Gaia Gaia-DR2 identifier
20- 34 F15.11 deg RAdeg Gaia DR2 right ascension (ICRS) at epoch 2015.5
36- 50 F15.11 deg DEdeg Gaia DR2 declination (ICRS) at epoch 2015.5
52- 56 F5.3 --- Pmemb RF membership probability
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Acknowledgements:
Xinhua Gao, xhgcczu(at)163.com
(End) Patricia Vannier [CDS] 08-Apr-2019