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Authordc.contributor.authorBrandeker, Alexis 
Authordc.contributor.authorJayawardhana, Ray es_CL
Authordc.contributor.authorKhavari, Parandis es_CL
Authordc.contributor.authorHaisch, Karl E. es_CL
Authordc.contributor.authorMardones Pérez, Diego es_CL
Admission datedc.date.accessioned2008-12-12T15:08:10Z
Available datedc.date.available2008-12-12T15:08:10Z
Publication datedc.date.issued2006-12-01
Cita de ítemdc.identifier.citationASTROPHYSICAL JOURNAL Volume: 652 Issue: 2 Pages: 1572-1584 Part: Part 1 Published: DEC 1 2006en
Identifierdc.identifier.issn0004-637X
Identifierdc.identifier.urihttps://repositorio.uchile.cl/handle/2250/124772
Abstractdc.description.abstractWe have carried out a sensitive high-resolution imaging survey of stars in the young (6-8 Myr), nearby (97 pc) compact cluster around eta Chamaeleontis to search for stellar and substellar companions. Our data were obtained using the NACO adaptive optics system on the ESO Very Large Telescope (VLT). Given its youth and proximity, any substellar companions are expected to be luminous, especially in the near-infrared, and thus easier to detect next to their parent stars. Here, we present VLT NACO adaptive optics imaging with companion detection limits for 17 eta Cha cluster members, and follow-up VLT ISAAC near-infrared spectroscopy for companion candidates. The widest binary detected is similar to 0."2, corresponding to the projected separation 20 AU, despite our survey being sensitive down to substellar companions outside 0."3, and planetary-mass objects outside 0."5. This implies that the stellar companion probability outside 0."3 and the brown dwarf companion probability outside 0."5 are less than 0.16 with 95% confidence. We compare the wide binary frequency of eta Cha to that of the similarly aged TW Hydrae association and estimate the statistical likelihood that the wide binary probability is equal in both groups to be less than 2 x 10(-4). Even though the eta Cha cluster is relatively dense, stellar encounters in its present configuration cannot account for the relative deficit of wide binaries. We thus conclude that the difference in wide binary probability in these two groups provides strong evidence for multiplicity properties being dependent on environment. In two appendices we derive the projected separation probability distribution for binaries, used to constrain physical separations from observed projected separations, and summarize statistical tools useful for multiplicity studies.en
Lenguagedc.language.isoenen
Keywordsdc.subjectLOW-MASS STARSen
Títulodc.titleDeficit of wide binaries in the eta chamaeleontis young clusteren
Document typedc.typeArtículo de revista


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