J/A+A/670/A108 Kinematic history of NGC 6611/M16 (Stoop+, 2023)
The early evolution of young massive clusters.
The kinematic history of NGC 6611/M16.
Stoop M., Kaper L., de Koter A., Guo D., Lamers H.J.G.L.M., Rieder S.
<Astron. Astrophys., 670, A108 (2023)>
=2023A&A...670A.108S 2023A&A...670A.108S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar ; Optical
Keywords: HII regions - open clusters and associations: individual: NGC 6611 -
astrometry - stars: kinematics and dynamics - stars: massive
Abstract:
Young massive clusters provide the opportunity to study the outcome of
the star formation process and the early evolution of star clusters.
In the first few million years, the (massive) stars dynamically
interact, producing runaways and affecting the initial (binary)
population.
Observing and interpreting the dynamics of young massive clusters is
key to our understanding of the star formation process and predicting
the outcome of stellar evolution, for example the number of
gravitational wave sources.
We have studied NGC 6611 in the Eagle Nebula (M16), a young massive
cluster hosting ∼19 O stars. We used Gaia EDR3 data to determine the
membership, age, cluster dynamics, and the kinematics of the massive
stars including runaways.
The membership analysis yields 137 members located at a mean distance
of 1706±7pc. The colour - absolute magnitude diagram reveals a blue
and a red population of pre-main-sequence stars, consistent with two
distinct populations of stars. In line with earlier studies, the
youngest (reddest) population has a mean extinction of
AV=3.6±0.1mag and an age of 1.3±0.2Myr, while the older
population of stars has a mean extinction of AV=2.0±0.1mag and an
age of 7.5±0.4Myr. The latter population is more spatially extended
than the younger generation of stars. We argue that most of the OB
stars belong to the younger population. We identify eight runaways
originating from the centre of NGC 6611, consistent with the dynamical
ejection scenario.
We have studied the kinematics of the O stars in detail and show that
∼50% of the O stars have velocities comparable to or greater than
the escape velocity. These O stars can be traced back to the centre of
NGC 6611 with kinematic ages ranging from 0 to 2Myr. These results
suggest that dynamical interactions played an important role in the
early evolution of NGC 6611, which is surprising considering the
relatively low current stellar density (0.1-1x103M☉/pc3).
Comparing our results to simulations of young massive clusters, the
initial radius of 0.1-0.5pc (needed to produce the observed O star
runaway fraction) is not consistent with that of NGC 6611. We propose
a scenario where the O stars initially form in wide binaries or higher
order systems and possibly harden through dynamical interactions.
Description:
We have studied the Eagle Nebula and its young massive cluster NGC
6611 in detail with Gaia EDR3.
List of 146 members of NGC 6611.
Objects:
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RA (2000) DE Designation(s)
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18 18 45.11 -13 47 31.1 NGC 6611 = M 16
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 115 146 Members of NGC 6611 with, if known, their
spectral, astrometric and photometric data
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaEDR3 Gaia EDR3 source_id
21- 44 A24 --- SpType Spectral type
47- 54 F8.4 deg RAdeg Right ascension (ICRS) at Ep=2015.5
56- 63 F8.4 deg DEdeg Declination (ICRS) at Ep=2015.5
65- 69 F5.3 mag plx Parallax
71- 76 F6.3 mas/yr pmRA* Proper motion along RA, pmRA*cosDE
78- 83 F6.3 mas/yr pmDE Proper motion along DE
85- 90 F6.1 km/s RV ?=- Radial velocity
92- 95 F4.1 km/s sigma ?=- Velocity dispersion
97-101 F5.2 mag B-V ?=- B-V colour index
103-108 F6.3 mag Vmag ?=- V magnitude
110-113 F4.2 mag E(B-V) ?=- Extinction
115 I1 --- Ref ?=- Reference (1)
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Note (1): References as follows:
1 = Sana et al. (2009MNRAS.400.1479S 2009MNRAS.400.1479S, Cat. J/MNRAS/400/1479)
2 = Evans et al. (2005A&A...437..467E 2005A&A...437..467E, Cat. J/A+A/437/467)
3 = Martayan et al. (2008A&A...489..459M 2008A&A...489..459M)
4 = Hillenbrand et al. (1993AJ....106.1906H 1993AJ....106.1906H, Cat. J/AJ/106/1906)
5 = Maiz Apellaniz et al. (2016ApJS..224....4M 2016ApJS..224....4M, Cat. J/ApJS/224/4)
6 = Gvaramadze & Bomans (2008A&A...490.1071G 2008A&A...490.1071G)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Jun-2023