HO Puppis: Not a Be Star, but a Newly Confirmed IW And-type Star
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Award ID(s):
Publication Date:
NSF-PAR ID:
10280402
Journal Name:
The Astrophysical Journal
Volume:
911
Issue:
1
Page Range or eLocation-ID:
51
ISSN:
0004-637X
1. ABSTRACT We present the star formation history (SFH) of the isolated (D ∼ 970 kpc) Local Group dwarf galaxy Wolf–Lundmark–Melotte (WLM) measured from colour–magnitude diagrams (CMDs) constructed from deep Hubble Space Telescope imaging. Our observations include a central ($0.5 \, r_h$) and outer field ($0.7 \, r_h$) that reach below the oldest main-sequence turn-off. WLM has no early dominant episode of star formation: 20 per cent of its stellar mass formed by ∼12.5 Gyr ago ($z$ ∼ 5). It also has an SFR that rises to the present with 50 per cent of the stellar mass within the most recent 5 Gyr ($z$ < 0.7). There ismore »