Cinemática de estrellas en cúmulos abiertos y asociaciones OB

The impact of the new observing techniques on radial velocity measurements is summarized here, along with some current efforts on proper motion studies. For stars with spectral types later than F5, results from CORAVEL and coudé-CCD spectroscopy achieve precision better than 0.5 km/sec (works by Mer...

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Detalles Bibliográficos
Autor principal: Morrell, Nidia Irene
Formato: Articulo Comunicacion
Lenguaje:Español
Publicado: 1992
Materias:
Astronomía
Galaxia
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/143614
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-143614
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Español
topic Astronomía
Galaxia
spellingShingle Astronomía
Galaxia
Morrell, Nidia Irene
Cinemática de estrellas en cúmulos abiertos y asociaciones OB
topic_facet Astronomía
Galaxia
description The impact of the new observing techniques on radial velocity measurements is summarized here, along with some current efforts on proper motion studies. For stars with spectral types later than F5, results from CORAVEL and coudé-CCD spectroscopy achieve precision better than 0.5 km/sec (works by Mermilliod, Mayor, Latham, Mathieu, among others). Recently, Andersen et ai, 1990, showed how new radial velocity observations of stars in intermediate age open clusters (namely: IC 4651 and NGC 3680) changed dramatically the current ideas about the extent and shape of each cluster's Main Sequence. Regarding early-type stars, we face a quite different situation. Spectral features are often broad and few in number, making hard to get accurate radial velocities. The highest accuracy obtained so far is around 2 km/sec., with coudé-CCD spectroscopy and high S/N (see, for example, works by Fekel, Morse, etc.). As an example of the improvements obtained, we review different studies on the binary frequency of IC 4665 (Abt and Snowden, 1969; Abt et al., 1972; Crampton et al., 1976; Morrell and Abt, 1991) where the higher accuracy achieved led to a binary frequency lower than the one observed previously. However, proper motions determined by Prosser, 1992, cast some doubt about the membership in the cluster of 2 of the 4 binaries, in a sample of 15 probable members. The need of radial velocity work in OB associations is obvious if we are interested in knowing the Present Date Mass Function for that groups, based on empirical data.
format Articulo
Comunicacion
author Morrell, Nidia Irene
author_facet Morrell, Nidia Irene
author_sort Morrell, Nidia Irene
title Cinemática de estrellas en cúmulos abiertos y asociaciones OB
title_short Cinemática de estrellas en cúmulos abiertos y asociaciones OB
title_full Cinemática de estrellas en cúmulos abiertos y asociaciones OB
title_fullStr Cinemática de estrellas en cúmulos abiertos y asociaciones OB
title_full_unstemmed Cinemática de estrellas en cúmulos abiertos y asociaciones OB
title_sort cinemática de estrellas en cúmulos abiertos y asociaciones ob
publishDate 1992
url http://sedici.unlp.edu.ar/handle/10915/143614
work_keys_str_mv AT morrellnidiairene cinematicadeestrellasencumulosabiertosyasociacionesob
bdutipo_str Repositorios
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