IALP   13078
INSTITUTO DE ASTROFISICA LA PLATA
Unidad Ejecutora - UE
artículos
Título:
Observational templates of star cluster disruption. The stellar group NGC 1901 in front of the Large Magellanic Cloud
Autor/es:
CARRARO, G.; DE LA FUENTE MARCOS, R.; VILLANOVA, S.; MONI BIDIN, C.; DE LA FUENTE MARCOS, C.; BAUMGARDT, H.; SOLIVELLA, G.
Revista:
ASTRONOMY AND ASTROPHYSICS
Referencias:
Año: 2007 vol. 466 p. 931 - 941
ISSN:
0004-6361
Resumen:
Context: Observations indicate that present-day star formation in the
Milky Way disk takes place in stellar ensembles or clusters rather than
in isolation. Bound, long-lived stellar groups are known as open
clusters. They gradually lose stars and are severely disrupted in their
final evolutionary stages, leaving an open cluster remnant made up of a
few stars. Aims: In this paper, we study in detail the stellar content
and kinematics of the poorly populated star cluster NGC 1901. This
object appears projected against the Large Magellanic Cloud. The aim of
the present work is to derive the current evolutionary status, binary
fraction, age, and mass of this stellar group. These are fundamental
quantities to compare with those from N-body models in order to study
the most general topic of star cluster evolution and dissolution.
Methods: The analysis is performed using wide-field photometry in the
UBVI pass-band, proper motions from the UCAC.2 catalog, and 3 epochs of
high-resolution spectroscopy, as well as results from extensive N-body
calculations. Results: The star group NGC 1901 is found to be an
ensemble of solar metallicity stars, 400±100 Myr old, with a core
radius of 0.23 pc, a tidal radius of 1.0 pc, and a location at
400±50 pc from the Sun. Out of 13 confirmed members, only 5
single stars have been found. Its estimated present-day binary fraction
is at least 62%. The calculated heliocentric space motion of the cluster
is not compatible with possible membership in the Hyades stream.
Conclusions: Our results show that NGC 1901 is a clear prototype of an
open cluster remnant characterized by a high value of the binary
fraction and a significant depletion of low-mass stars. In light of
numerical simulations, this is compatible with NGC 1901 being what
remains of a larger system initially made of 500-750 stars.
Data for Fig. 4 is only available in electronic form at the CDS via
anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?/A+A/466/931 Table 1 is only
available in electronic form at http://www.aanda.org