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: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 91 27 Program stars, parallaxes, and proper motions taba1-a3.dat 64 136 Be59 stellar radial velocities -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Note (1): Notes as follows: a = 2MASS J00012663+6723461, WISE J000126.63+672346.1, UCAC4 787-000033 b = BD+66 1673 -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Acknowledgements: Anlaug Amanda Djupvik, amanda(at)not.iac.es, Nordic Optical Telescope
(End) Anlaug Amanda Djupvik [NOT], Patricia Vannier [CDS] 26-Apr-2022
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