THE CURIOUS MORPHOLOGY AND ORIENTATION OF ORION PROPLYD HST-10

Journal Article · Sat Feb 01 04:00:00 EST 2014 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/781/2/L37· OSTI ID:22364006

Shuping, R. Y. ^[1]; Kassis, Marc ^[2]; Bally, John ^[3]

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1. Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States)
2. W. M. Keck Observatory, 65-1120 Mamalahoa Hwy, Kamuela, HI 96743-8431 (United States)
3. Center for Astrophysics and Space Astronomy, University of Colorado, 391 UCB, Boulder, CO 80309-0001 (United States)

HST-10 is one of the largest proplyds in the Orion Nebula and is located approximately 1' SE of the Trapezium. Unlike other proplyds in Orion, however, the long-axis of HST-10 does not align with θ{sup 1} C, but is instead aligned with the rotational axis of the HST-10 disk. This cannot be easily explained using current photoevaporation models. In this Letter, we present high spatial resolution near-infrared images of the Orion proplyd HST-10 using Keck/NIRC2 with the Laser Guide Star Adaptive Optics system, along with multi-epoch analysis of HH objects near HST-10 using Hubble Space Telescope (HST) WFPC2 and Advanced Camera for Surveys cameras. Our narrowband near-IR images resolve the proplyd ionization front (IF) and circumstellar disk down to 23 AU at the distance to Orion in Br γ, He I, H{sub 2}, and polycyclic aromatic hydrocarbon (PAH) emission. Br γ and He I emission primarily trace the IF (with the disk showing prominently in silhouette), while the H{sub 2} and PAH emission trace the surface of the disk itself. PAH emission also traces small dust grains within the proplyd envelope which is asymmetric and does not coincide with the IF. The curious morphology of the PAH emission may be due to UV heating by both θ{sup 1} COri and θ{sup 2} AOri. Multi-epoch HST images of the HST-10 field show proper motion of three knots associated with HH 517, clearly indicating that HST-10 has a jet. We postulate that the orientation of HST-10 is determined by the combined ram pressure of this jet and the FUV-powered photo-ablation flow from the disk surface.

• OSTI ID: 22364006
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 781; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABLATION
APPROXIMATIONS
ASYMMETRY
CAMERAS
COSMIC DUST
EMISSION
HYDROGEN
IMAGES
IONIZATION
JETS
NEBULAE
OPTICS
POLYCYCLIC AROMATIC HYDROCARBONS
PROPER MOTION
SPACE
SPATIAL RESOLUTION
STARS
STELLAR WINDS
SURFACES
TELESCOPES