J/A+A/663/A111 Expanding shells around young cluster Be 59 (Gahm+, 2022)
Expanding shells around young clusters - S 171/Be 59.
Gahm G.F., Wilhelm M.J.C., Persson C.M., Djupvik A.A., Portegies Zwart S.F.
<Astron. Astrophys. 663, A111 (2022)>
=2022A&A...663A.111G 2022A&A...663A.111G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Radial velocities
Keywords: HII regions - ISM: molecules - ISM: kinematics and dynamics -
evolution - stars: kinematics and dynamics
Abstract:
Some HII regions that surround young stellar clusters are bordered by
molecular shells that appear to expand at a rate inconsistent with our
current model simulations. In this study we focus on the dynamics of
Sharpless 171 (including NGC 7822), which surrounds the cluster
Berkeley 59.
We aim to compare the velocity pattern over the molecular shell with
the mean radial velocity of the cluster for estimates of the expansion
velocities of different shell structures, and to match the observed
properties with model simulations.
Optical spectra of 27 stars located in Berkeley 59 were collected at
the Nordic Optical Telescope, and a number of molecular structures
scattered over the entire region were mapped in 13CO(1-0) at Onsala
Space Observatory.
We obtained radial velocities and MK classes for the cluster's stars.
At least four of the O stars are found to be spectroscopic binaries,
in addition to one triplet system. From these data we obtain the mean
radial velocity of the cluster. From the 13CO spectra we identify
three shell structures, expanding relative to the cluster at moderate
velocity (4km/s), high velocity (12km/s), and in between. The
high-velocity cloudlets extend over a larger radius and are less
massive than the low-velocity cloudlets. We performed a model
simulation to understand the evolution of this complex.
Our simulation of the Sharpless 171 complex and Berkeley 59 cluster
demonstrates that the individual components can be explained as a
shell driven by stellar winds from the massive cluster members.
However, our relatively simple model produces a single component.
Modelling of the propagation of shell fragments through a uniform
interstellar medium demonstrates that dense cloudlets detached from
the shell are decelerated less efficiently than the shell itself. They
can reach greater distances and retain higher velocities than the
shell.
Description:
Optical spectroscopy with FIES at the Nordic Optical Telescope was
used to determine the radial velocity at a number of epochs for the
brightest stars in the Berkeley 59 cluster, of which several are found
to be spectroscopic binaries or even triples. The table taba1-a3.dat
contain tables A1-A3 in the Appendix A of the paper, i.e. the
individual epoch stellar radial velocities and here with the object
coordinates added. For other designations of the targets, as well as
parallax and proper motions, see Table 2 in the paper, and for
magnitudes, colours, spectral types and extinction, see Table 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 91 27 Program stars, parallaxes, and proper motions
taba1-a3.dat 64 136 Be59 stellar radial velocities
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See also:
J/other/BASI/35.53 : JH photometry of Berkeley 59 (Sharma+, 2007)
J/MNRAS/383/1241 : UBVIc photometry of cluster Berkeley 59 (Pandey+, 2008)
J/AJ/155/44 : Properties of PMS stars in Berkeley 59 (Panwar+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Object Designation used in paper
12 A1 --- n_Object [ab] Note on Object (1)
14- 35 A22 --- ONames Other names
37- 38 I2 h RAh Right Ascension (J2000) at Ep=1989.0
40- 41 I2 min RAm Right Ascension (J2000) at Ep=1989.0
43- 46 F4.1 s RAs Right Ascension (J2000) at Ep=1989.0
48 A1 --- DE- Declination sign (J2000) at Ep=1989.0
49- 50 I2 deg DEd Declination (J2000) at Ep=1989.0
52- 53 I2 arcmin DEm Declination (J2000) at Ep=1989.0
55- 56 I2 arcsec DEs Declination (J2000) at Ep=1989.0
58- 62 F5.2 mas Plx ? Parallax
64- 68 F5.3 mas e_Plx ? rms uncertainty on Parallax
69- 74 F6.2 mas/yr pmRA ? Proper motion along RA, pmRA*cosDE
76- 79 F4.2 mas/yr e_pmRA ? rms uncertainty on pmRA
81- 86 F6.2 mas/yr pmDE ? Proper motion along DE
88- 91 F4.2 mas/yr e_pmDE ? rms uncertainty on pmDE
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Note (1): Notes as follows:
a = 2MASS J00012663+6723461, WISE J000126.63+672346.1, UCAC4 787-000033
b = BD+66 1673
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Byte-by-byte Description of file: taba1-a3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Object Designation used in paper
11 A1 --- m_Object [ABC] Multiplicity index on Object
15- 16 I2 h RAh Right Ascension (J2000) at Ep=1989.0
18- 19 I2 min RAm Right Ascension (J2000) at Ep=1989.0
21- 24 F4.1 s RAs Right Ascension (J2000) at Ep=1989.0
26 A1 --- DE- Declination sign (J2000) at Ep=1989.0
27- 28 I2 deg DEd Declination (J2000) at Ep=1989.0
30- 31 I2 arcmin DEm Declination (J2000) at Ep=1989.0
33- 34 I2 arcsec DEs Declination (J2000) at Ep=1989.0
38- 51 F14.6 d HJD Heliocentric Julian Date
53- 58 F6.1 km/s RV Radial Velocity
61- 64 F4.1 km/s e_RV Error in Radial Velocity
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Acknowledgements:
Anlaug Amanda Djupvik, amanda(at)not.iac.es, Nordic Optical Telescope
(End) Anlaug Amanda Djupvik [NOT], Patricia Vannier [CDS] 26-Apr-2022