PROPLYDS AROUND A B1 STAR: 42 ORIONIS IN NGC 1977

Journal Article · Wed Jul 20 04:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/826/1/L15· OSTI ID:22654268

Kim, Jinyoung Serena; Fang, Min ^[1]; Clarke, Cathie J. ^[2]; Facchini, Stefano ^[3]

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1. Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721-0065 (United States)
2. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
3. Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany)

We present the discovery of seven new proplyds (i.e., sources surrounded by cometary H α emission characteristic of offset ionization fronts (IFs)) in NGC 1977, located about 30′ north of the Orion Nebula Cluster (ONC) at a distance of ∼400 pc. Each of these proplyds is situated at projected distances 0.04–0.27 pc from the B1V star 42 Orionis ( c Ori), which is the main source of UV photons in the region. In all cases the IFs of the proplyds are clearly pointing toward the common ionizing source, 42 Ori, and six of the seven proplyds clearly show tails pointing away from it. These are the first proplyds to be found around a B star, with previously known examples instead being located around O stars, including those in the ONC around θ {sup 1} Ori C. The radii of the offset IFs in our proplyds are between ∼200 and 550 au; two objects also contain clearly resolved central sources that we associate with disks of radii 50–70 au. The estimated strength of the FUV radiation field impinging on the proplyds is around 10–30 times less than that incident on the classic proplyds in the ONC. We show that the observed proplyd sizes are however consistent with recent models for FUV photoevaporation in relatively weak FUV radiation fields.

• OSTI ID: 22654268
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 826; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
EMISSION
IONIZATION
NEBULAE
PHOTONS
PROTOPLANETS
STAR CLUSTERS
STARS