2024-03-28T09:20:20Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1676142020-12-10T15:48:49Zcom_10261_97com_10261_4com_10261_44col_10261_350col_10261_297
The Gaia-ESO Survey: Structural and dynamical properties of the young cluster Chamaeleon i
Sacco, G. G.
Spina, L.
Randich, S.
Palla, F.
Parker, R. J.
Jeffries, R.D.
Jackson, R. J.
Meyer, M. R.
Mapelli, M.
Lanzafame, A.C.
Bonito, R.
Damiani, F.
Franciosini, E.
Frasca, A.
Klutsch, A.
Prisinzano, L.
Tognelli, E.
Degl'Innocenti, S.
Prada Moroni, P. G.
Alfaro, Emilio J.
Micela, G.
Prusti, T.
Barrado y Navascués, David
Biazzo, K.
Bouy, Hervé
Bravi, L.
López-Santiago, J.
Wright, N.J.
Bayo, A.
Gilmore, G.
Bragaglia, A.
Flaccomio, E.
Koposov, S.
Pancino, E.
Casey, A. R.
Costado, M. T.
Donati, P.
Hourihane, A.
Jofré, P.
Lardo, C.
Lewis, J.
Magrini, L.
Monaco, L.
Morbidelli, L.
Sousa, S. G.
Worley, C. C.
Zaggia, S.
Ministero dell'Istruzione, dell'Università e della Ricerca
Istituto Nazionale di Astrofisica
European Research Council
Fundação para a Ciência e a Tecnologia (Portugal)
Open clusters and associations: Individual: Chamaeleon I
Techniques: Spectroscopic
Stars: Pre-main sequence
Stars: Kinematics and dynamics
Investigating the physical mechanisms driving the dynamical evolution of young star clusters is fundamental to our understanding of the star formation process and the properties of the Galactic field stars. The young (~2 Myr) and partially embedded cluster Chamaeleon I is one of the closest laboratories for the study of the early stages of star cluster dynamics in a low-density environment. The aim of this work is to study the structural and kinematical properties of this cluster combining parameters from the high-resolution spectroscopic observations of the Gaia-ESO Survey with data from the literature. Our main result is the evidence of a large discrepancy between the velocity dispersion (σ = 1.14 ± 0.35 km s) of the stellar population and the dispersion of the pre-stellar cores (~0.3 km s) derived from submillimeter observations. The origin of this discrepancy, which has been observed in other young star clusters, is not clear. It has been suggested that it may be due to either the effect of the magnetic field on the protostars and the filaments or to the dynamical evolution of stars driven by two-body interactions. Furthermore, the analysis of the kinematic properties of the stellar population puts in evidence a significant velocity shift (~1 km s) between the two subclusters located around the north and south main clouds of the cluster. This result further supports a scenario where clusters form from the evolution of multiple substructures rather than from a monolithic collapse. Using three independent spectroscopic indicators (the gravity indicator γ, the equivalent width of the Li line at 6708 Å, and the Hα 10% width), we performed a new membership selection. We found six new cluster members all located in the outer region of the cluster, proving that Chamaeleon I is probably more extended than previously thought. Starting from the positions and masses of the cluster members, we derived the level of substructure Q, the surface density Σ, and the level of mass segregation Λ of the cluster. The comparison between these structural properties and the results of N-body simulations suggests that the cluster formed in a low-density environment, in virial equilibrium or a supervirial state, and highly substructured.© 2017 ESO.
This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR) in the form of the grant >Premiale VLT 2012>. This work has been partially supported by PRIN-INAF-2014. The results presented here benefited from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. M.M. acknowledges financial support from the Italian Ministry of Education, University and Research (MIUR) through grant FIRB 2012 RBFR12PM1F, from INAF through grant PRIN-2014-14, and from the MERAC Foundation. S.G.S. acknowledges the support by Fundacao para a Ciencia e Tecnologia (FCT) through national funds and a research grant (project Ref. UID/FIS/04434/2013, and PTDC/FIS-AST/7073/2014). S.G.S. also acknowledge the support from FCT through Investigador FCT contract of reference IF/00028/2014 and POPH/FSE (EC) by FEDER funding through the program Programa Operacional de Factores de Competitividade COMPETE.
Peer Reviewed
2018-07-16T06:47:45Z
2018-07-16T06:47:45Z
2017
2018-07-16T06:47:46Z
artículo
http://purl.org/coar/resource_type/c_6501
doi: 10.1051/0004-6361/201629698
issn: 1432-0746
Astronomy and Astrophysics 601: A97 (2017)
http://hdl.handle.net/10261/167614
10.1051/0004-6361/201629698
http://dx.doi.org/10.13039/501100001871
http://dx.doi.org/10.13039/501100003407
http://dx.doi.org/10.13039/501100005184
http://dx.doi.org/10.13039/501100000781
#PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/FP7/320360
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