J/A+A/675/A28 Properties of Group X candidate members (Olivares+, 2023)
The cosmic waltz of Coma Berenices and Latyshev 2 (Group X).
Membership, phase-space structure, mass, and energy distributions.
Olivares J., Lodieu N., Bejar V.J.S., Martin E.L., Zerjal M., Galli P.A.B.
<Astron. Astrophys. 675, A28 (2023)>
=2023A&A...675A..28O 2023A&A...675A..28O (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Associations, stellar ; Space velocities
Keywords: open clusters and associations: individual: Coma Berenices -
stars: kinematics and dynamics - solar neighbourhood -
methods: statistical - astrometry
Abstract:
Open clusters (OCs) are fundamental benchmarks where theories of star
formation and stellar evolution can be tested and validated. Coma
Berenices (Coma Ber) and Latyshev 2 (Group X) are the second and third
OCs closest to the Sun, making them excellent targets to search for
low-mass stars and ultra-cool dwarfs. In addition, this pair will
experience a flyby in 10-16Myr which makes it a benchmark to test OCs
pair interactions.
We aim at analysing the membership, luminosity, mass, phase-space
(i.e., positions and velocities), and energy distributions for
Coma Ber and Latyshev 2 and test the hypothesis of the mixing of their
populations at the encounter time.
We develop a new phase-space membership methodology and apply it to
Gaia data. With the recovered members we infer the phase-space,
luminosity and mass distributions using publicly available Bayesian
inference codes. Then, with a publicly available orbit integration
code and members' positions and velocities, we integrate their orbits
20Myr into the future.
In Coma Ber, we identify 302 candidate members distributed in the core
and tidal tails. The tails are dynamically cold and asymmetrically
populated. The stellar system called Group X is made of two
structures: the disrupted OC Latyshev 2 (186 candidate members) and a
loose stellar association called Mecayotl 1 (146 candidate members),
both of them will fly by Coma Ber in 11.3±0.5Myr and 14.0±0.6Myr,
respectively, and each other in 8.1±1.3Myr.
We study the dynamical properties of the core and tails of Coma Ber
and also confirm the existence of the OC Latyshev 2 and its neighbour
stellar association Mecayotl 1. Although these three systems will
experience encounters we find no evidence supporting the mixing of
their populations.
Description:
Table containing the properties of the 634 candidate members: 302 in
Coma Ber, 186 in Latyshev 2 and 146 in Mecayotl 1. It comprises, for
each candidate member, its Gaia DR3 source identifier, parent group,
right ascension, and declination, both from Gaia DR3. The remaining
properties were inferred using Markov Chain Monte Carlo methods and
the statistics of the resulting samples are provided as mean values and
standard deviations or percentiles and maximum-a-posteriori (i.e. the
mode of the posterior distribution).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled1.dat 288 634 Properties of the 634 candidate members
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Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaDR3 Gaia DR3 source identifier
21- 33 A13 --- Group Parent group
35- 52 F18.16 --- Pmemb [0.99/1.0] Membership probability to the
parent group
54- 71 F18.14 deg RAdeg [152.39/253.11] Gaia DR3 Right Ascencion
(ICRS) at Ep=2016.0
73- 92 F20.16 deg DEdeg [-6.87/73.23] Gaia DR3 Declination
(ICRS) at Ep=2016.0
94-101 F8.3 pc meanX [-109.68/-20.25] Mean X coordinate
103-107 F5.3 pc s_meanX [0.04/3.05] Standard deviation of the
X coordinate
109-115 F7.3 pc meanY [-81.84/55.66] Mean Y coordinate
117-121 F5.3 pc s_meanY [0.0/3.23] Standard deviation of the
Y coordinate
123-130 F8.3 pc meanZ [-13.52/113.33] Mean Z coordinate
132-136 F5.3 pc s_meanZ [0.02/4.18] Standard deviation of the
Z coordinate
138-143 F6.3 km/s meanU [-5.2/-0.09] Mean U coordinate
145-149 F5.3 km/s s_meanU [0.03/0.86] Standard deviation of the
U coordinate
151-155 F5.3 km/s meanV [1.37/8.94] Mean V coordinate
157-161 F5.3 km/s s_meanV [0.01/0.69] Standard deviation of the
V coordinate
163-168 F6.3 km/s meanW [-9.23/-1.5] Mean W coordinate
170-174 F5.3 km/s s_meanW [0.01/1.32] Standard deviation of the
W coordinate
176-193 F18.16 Msun b_Mass [0.06/2.08] Percentil 2.5 of the
mass distribution
195-212 F18.16 Msun Mass [0.06/2.5] Maximum-A-Posteriori of the
mass distribution
214-231 F18.16 Msun B_Mass [0.06/2.49] Percentil 97.5 of the
mass distribution
233-250 F18.16 mag b_AV [0.0/0.03] Percentil 2.5 of the
Av distribution
252-269 F18.16 mag AV [0.0/0.1] Maximum-A-Posteriori of the
Av distribution
271-288 F18.16 mag B_AV [0.07/0.1] Percentil 97.5 of the
Av distribution
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Acknowledgements:
Javier Olivares, jolivares(at)dia.uned.es
(End) Patricia Vannier [CDS] 19-Apr-2023