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Searching for Be Stars in the Open Clusters with PTF/iPTF. I. Cluster Sample and Be Star Candidates

Yu, Po-Chieh and Yu, Chang-Hsien and Lee, Chien-De and Lin, Chien-Cheng and Hsia, Chih-Hao and Chang, Chang-Kao and Chen, I-Chenn and Ngeow, Chow-Choong and Ip, Wing-Huen and Chen, Wen-Ping and Laher, Russ and Surace, Jason and Kulkarni, Shrinivas R. (2018) Searching for Be Stars in the Open Clusters with PTF/iPTF. I. Cluster Sample and Be Star Candidates. Astronomical Journal, 155 (2). Art. No. 91. ISSN 1538-3881. http://resolver.caltech.edu/CaltechAUTHORS:20180131-131424122

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Abstract

We conducted a search for Be star candidates in open clusters using Hα imaging photometry of the Palomar Transient Factory Survey to investigate some connections among Be star phenomena, cluster environments, and ages. Stellar members of clusters were identified by spatial distributions, near-infrared magnitudes and colors, and by proper motions. Among 104 open clusters, we identified 96 Be star candidates in 32 clusters; 11 of our candidates have been reported in previous studies. We found that the clusters with age 7.5 < log(t(year)) ⩽ 8.5 tend to have more Be star candidates; there is about a 40% occurrence rate within this age bin. The clusters in this age bin also tend to have a higher Be fraction N(Be)/N(Be+B-type). These results suggest that the environments of young and intermediate clusters are favorable to the formation of Be phenomena. Spatial distribution of Be star candidates with different ages implies that they do not form preferentially in the central regions. Furthermore, we showed that the mid-infrared (MIR) colors of the Be star candidates are similar to known Be stars, which could be caused by free–free emission or bound-free emission. Some Be star candidates might have no circumstellar dust according to their MIR colors. Finally, among 96 Be candidates, we discovered that one Be star candidate FSR 0904-1 exhibits long-term variability on the timescale of ~2000 days with an amplitude of 0.2–0.3 mag, indicating a long timescale of disk evolution.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-3881/aaa45bDOIArticle
http://iopscience.iop.org/article/10.3847/1538-3881/aaa45b/metaPublisherArticle
ORCID:
AuthorORCID
Yu, Po-Chieh0000-0001-8894-0854
Lee, Chien-De0000-0002-3142-7299
Chen, I-Chenn0000-0002-1497-9884
Ngeow, Chow-Choong0000-0001-8771-7554
Chen, Wen-Ping0000-0003-0262-272X
Surace, Jason0000-0001-7291-0087
Kulkarni, Shrinivas R.0000-0001-5390-8563
Additional Information:© 2018 American Astronomical Society. Received 2017 June 6. Accepted 2017 December 26. Published 2018 January 29. This work is supported in part by the Ministry of Science and Technology of Taiwan under grants MOST 105-2119-M-008-003 (W.-H.I.), MOST 103-2112-M-008-024-MY3 (W.-P.C.), MOST 104-2112-M-008-012-MY3 (C.-C.N.), MOST 104-2112-M-008-014-MY3 (C.-K.C), and MOST 106-2917-I-564-042 (C.-C.L.). This work is also supported by the Science and Technology Development Fund of Macau (project codes: 039/2013/A2 and 017/2014/A1). This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This research has made use of the WEBDA database, operated at the Department of Theoretical Physics and Astrophysics of the Masaryk University.
Group:Infrared Processing and Analysis Center (IPAC), IPTF
Funders:
Funding AgencyGrant Number
Ministry of Science and Technology (Taipei)MOST-105-2119-M-008-003
Ministry of Science and Technology (Taipei)MOST 103-2112-M-008-024-MY3
Ministry of Science and Technology (Taipei)MOST 104-2112-M-008-012-MY3
Ministry of Science and Technology (Taipei)MOST 104-2112-M-008-014-MY3
Ministry of Science and Technology (Taipei)MOST 106-2917-I-564-042
Macau Science and Technology Development Fund039/2013/A2
Macau Science and Technology Development Fund017/2014/A1
NSFUNSPECIFIED
NASA/JPL/CaltechUNSPECIFIED
Subject Keywords:open clusters and associations: general; stars: emission-line, Be; stars: general; surveys
Record Number:CaltechAUTHORS:20180131-131424122
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180131-131424122
Official Citation:Po-Chieh Yu et al 2018 AJ 155 91
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84604
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:31 Jan 2018 22:13
Last Modified:31 Jan 2018 22:13

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