J/A+A/694/A258 Tidal tails of nearby open clusters (Risbud+, 2025)
Tidal tails of nearby open clusters I. Mapping with Gaia DR3.
Risbud D., Jadhav V.V., Kroupa P.
<Astron. Astrophys. 694, A258 (2025)>
=2025A&A...694A.258R 2025A&A...694A.258R (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open ; Positional data ; Optical
Keywords: methods: observational - Galaxy: kinematics and dynamics -
open clusters and associations: general
Abstract:
Tidal tails of open clusters are the result of the stellar evaporation
from the cluster due to the Galactic potential and the
internal dynamics. With the recent availability of high precision
data, tidal tails are being detected for most of the nearby open
clusters.
In this work, we aim to identify the tidal tail members for all open
clusters within a distance of 400 pc which are older than 100 Myr and
have >100 members using model-independent methods.
We used the convergent point method to identify the co-moving stars
near the open clusters using Gaia DR3 data. A new method called
"self compact convergent point method" was proposed and applied to
some of the clusters which performed better in tracing the tails. We
also analysed the colour-magnitude diagrams and orbital energy to
diagnose possible contamination.
19 out of 21 clusters have tidal tails. 5 of them have been discovered
for the first time through this work. The typical span of the tidal
tails is 20-200 pc with 30-700 member stars in the region inside
the tidal radius and the tidal tails. 4 out of 19 tidal tails are
tilted away from direction of the Galactic Centre which defy the known
theory of the formation of the tidal tails. The luminosity function of
the tails and clusters are consistent with each other and with the
canonical stellar IMF, while systematically larger trailing tail
radial velocities than the leading tail radial velocities were
observed for the first time.
The convergent point method is useful to detect tidal tails on ~=100pc
scale for clusters closer than 400pc. Further analysis of theoretical
N-body models is required to understand the incompleteness and biases
in the current sample of tidal tails.
Description:
Tidal tails of open star clusters within 400pc from the Sun.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 60 19 List of studied clusters
members.dat 286 10762 Tidal tails of open star clusters within 400pc
from the Sun
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/627/A4 : Praesepe (NGC 2632) and its tidal tails (Roeser+, 2019)
J/ApJ/912/162 : Open clusters in solar neighborhood (Pang+, 2021)
J/A+A/645/A84 : Coronae of nearby star clusters (Meingast+, 2021)
J/A+A/624/L11 : Coma Berenices neighbor moving group (Fuernkranz+, 2019)
J/ApJ/877/12 : Coma Ber and a Neighbor Stellar Group tidal tails (Tang+, 2019)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Cluster Name of the cluster
16- 17 I2 h RAh Simbad right ascension (J2000)
19- 20 I2 min RAm Simbad right ascension (J2000)
22- 26 F5.2 s RAs Simbad right ascension (J2000)
28 A1 --- DE- Simbad declination sign (J2000)
29- 30 I2 deg DEd Simbad declination (J2000)
32- 33 I2 arcmin DEm Simbad declination (J2000)
35- 38 F4.1 arcsec DEs Simbad declination (J2000)
40- 43 I4 --- Nmemb Number of members in members.dat file
45- 60 A16 --- SName Simbad name
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Byte-by-byte Description of file: members.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Cluster Name of the cluster
15- 33 I19 --- GaiaDR3 Gaia DR3 source_id
35- 44 F10.6 deg RAdeg Right ascension (ICRS) at Ep=2016
46- 55 F10.6 deg DEdeg Declination (ICRS) at Ep=2016
57- 66 F10.6 mas plx Absolute stellar parallax
68- 78 F11.6 mas/yr pmRA Proper motion in right ascension
80- 90 F11.6 mas/yr pmDE Proper motion in declination
92- 97 F6.3 mag BP-RP Gaia DR3 BP minus RP colour
99-104 F6.3 mag Gmag Gaia DR3 mean G magnitude
106-111 F6.3 mag GMAG Absolute G magnitude
113-119 F7.2 pc X Solar system barycentric cartesian
X coordinate
121-127 F7.2 pc Y Solar system barycentric cartesian
Y coordinate
129-135 F7.2 pc Z Solar system barycentric cartesian
Z coordinate
137-142 F6.2 km/s Delvpll Velocity parallel to the convergent
point (Delvparallel)
144-148 F5.2 km/s vperobs Velocity perpendicular to the
convergent point (vperpendicularobs)
150-161 F12.6 mas/yr pmRAc Proper motion in right ascension
corrected for solar reflex motion
163-173 F11.6 mas/yr pmDEc Proper motion in declination
corrected for solar reflex motion
175-185 F11.6 deg phi1 Tail aligned longitude
187-196 F10.6 deg phi2 Tail aligned latitude
198-209 F12.6 mas/yr pmphi1cosphi2 Proper motion in phi1, pmph1*cosphi2
211-221 F11.6 mas/yr pmphi2 Proper motion in phi2
223-226 I4 --- 5DNeighcount Number of neighbors in 5 dimensions
228 I1 --- FleadingTail [0/1] Flag indicating the star in
leading tail
230 I1 --- FtrailingTail [0/1] Flag indicating the star in
trailing tail
232 I1 --- FwithinTidRad [0/1] Flag indicating the star in
within the tidal radius
234 I1 --- FCorrSamp [0/1] Flag indicating the star is
a part of corrected sample
236-243 A8 --- Method Method used
245-267 F23.18 km/s RV ?=- Radial Velocity
269-275 F7.2 kpc.km/s Lz ?=- Z-component of orbital angular
momentum of star
277-286 F10.2 10+5km2/s2 Energy ?=- Total orbital Energy of star
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Acknowledgements:
Dhanraj Risbud, University of Bonn, dvr.blackhole(at)gmail.com
(End) Patricia Vannier [CDS] 13-Jan-2025