J/A+A/627/A119 Extended halo of NGC 2682 (M 67) (Carrera+ 2019)
The extended halo of NGC 2682 (M 67) from Gaia DR2.
Carrera R., Pasquato M., Vallenari A., Balaguer-Nunez L.,
Cantat-Gaudin T., Mapelli M., Bragaglia A., Bossini D., Jordi C.,
Galadi-Enriquez D., Solano E.
<Astron. Astrophys. 627, A119 (2019)>
=2019A&A...627A.119C 2019A&A...627A.119C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar
Keywords: astrometry - open clusters and associations: individual: NGC 2682
Abstract:
NGC 2682 is a nearby open cluster that is approximately 3.5Gyr old.
Dynamically, most open clusters are expected to dissolve on shorter
timescales of ~=1Gyr. That it has survived until now means that NGC
2682 was likely much more massive in the past and is bound to have an
interesting dynamical history.
We investigate the spatial distribution of the stars in NGC 2682 to
constrain dynamical evolution of the cluster. We particularly focus on
the marginally bound stars in the cluster outskirts.
We used Gaia DR2 data to identify NGC 2682 members up to a distance of
∼150pc (10°). The two methods Clusterix and UPMASK were applied to
this end. We estimated distances to obtain 3D stellar positions using
a Bayesian approach to parallax inversion, with an appropriate prior
for star clusters. We calculated the orbit of NGC 2682 using the
GRAVPOT16 software.
The cluster extends up to 200' (50pc), which implies that its size
is at least twice as large as previously believed. This exceeds the
cluster Hill sphere based on the Galactic potential at the distance of
NGC 2682.
The extra-tidal stars in NGC 2682 may originate from external
perturbations such as disc-shocking or dynamical evaporation from
two-body relaxation. The former origin is plausible given the orbit of
NGC 2682, which crossed the Galactic disc ~=40Myr ago.
Description:
Stellar sample used in the analysis of the spatial distribution of the
M 67 stellar populations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 108 952 Stellar sample and membership probabilities
used in this study
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Star Star identification (Gaia DR2 sourve_id)
22- 30 F9.5 deg RAdeg Gaia DR2 right ascension (ICRS)
at epoch 2015.5
34- 41 F8.5 deg DEdeg Gaia DR2 declination (ICRS) at epoch 2015.5
46- 50 F5.3 mas Plx Gaia DR2 parallax
53- 59 F7.3 mas/yr pmRA Gaia DR2 proper motion along RA, pmRA*cosDE
63- 68 F6.3 mas/yr pmDE Gaia DR2 proper motion along DE
72- 77 F6.3 mag Gmag Gaia DR2 mean G magnitude
81- 86 F6.3 mag BPmag Gaia DR2 mean BP magnitude
90- 95 F6.3 mag RPmag Gaia DR2 mean RP magnitude
97 I1 --- Type [1/6] Star type (1)
99-102 F4.2 --- Pupmask UPMASK membership probability
104-108 F5.3 --- Pclusterix Clusterix membership probability
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Note (1): Stellar evolution stage of the stars used in the analysis as follows:
1 = red clump
2 = red giant branch
3 = subgiant branch
4 = Turn-off
5 = Main sequence
6 = Binaries
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Acknowledgements:
Ricardo Carrera, jimenez.carrera(at)inaf.it
(End) R. Carrera [Obs. astron. Padova, INAF], P. Vannier [CDS] 05-Jul-2019