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Deep, Wide-field CCD Photometry for the Open Cluster NGC 3532

Clem, James L. and Landolt, Arlo U. and Hoard, D. W. and Wachter, Stefanie (2011) Deep, Wide-field CCD Photometry for the Open Cluster NGC 3532. Astronomical Journal, 141 (4). Art. No. 115. ISSN 0004-6256.

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We present the results of a deep, wide-field CCD survey for the open cluster NGC 3532. Our new BV(RI) c photometry effectively covers a one square degree area and reaches an unprecedented depth of V ~ 21 to reveal that NGC 3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams (CMDs), including supplementing our photometry with JHK_s data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main-sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence. Our results confirm previous findings that NGC 3532 lies fairly near to the Sun [(m – M)_0 = 8.46 ± 0.05; 492^(+12)_(–11) pc] and has an extremely low reddening for its location near the Galactic plane [E(B – V) = 0.028 ± 0.006]. Moreover, an age of ~300 Myr has been derived for the cluster by fitting a set of overshooting isochrones to the well-populated upper main sequence. This new photometry also extends faint enough to reach the cluster white dwarf sequence, as confirmed by our photometric recovery of eight spectroscopically identified members of the cluster. Using the location of these eight members, along with the latest theoretical cooling tracks, we have identified ~30 additional white dwarf stars in the [V, (B – V)] CMD that have a high probability of belonging to NGC 3532. Reassuringly, the age we derive from fitting white dwarf isochrones to the locus of these stars, 300 ± 100 Myr, is consistent with the age derived from the turnoff. Our analysis of the photometry also includes an estimation of the binary star fraction as well as a determination of the cluster's luminosity and mass functions.

Item Type:Article
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URLURL TypeDescription DOIArticle
Hoard, D. W.0000-0002-6800-6519
Additional Information:© 2011 American Astronomical Society. Received 2010 November 3; accepted 2011 January 13; published 2011 March 1. The authors extend their thanks to the staff of the CTIO for their superb aid during the data acquisition process. Thanks also go to K. Hainline, who helped us take an initial first look at these data. This work has made use of BaSTI web tools at This project has been funded by National Science Foundation grants AST 95-28177 and AST 08-03158 to A.U.L.
Funding AgencyGrant Number
NSFAST 95-28177
NSFAST 08-03158
Subject Keywords:open clusters and associations: individual (NGC 3532); techniques: photometric
Issue or Number:4
Classification Code:PACS: 95.80.+p; 97.10.Zr; 98.20.di; 97.20.Rp; 95.85.Kr
Record Number:CaltechAUTHORS:20110328-100710390
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Official Citation:Deep, Wide-field CCD Photometry for the Open Cluster NGC 3532 James L. Clem et al. 2011 The Astronomical Journal 141 115
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:23126
Deposited By: Ruth Sustaita
Deposited On:29 Mar 2011 20:24
Last Modified:17 Nov 2019 01:59

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