Three-dimensional shock structure of the Orion KL outflow with IGRINS

Journal Article · Tue Dec 20 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/833/2/275· OSTI ID:22869623

Oh, Heeyoung; Yuk, In-Soo; Park, Byeong-Gon; Park, Chan; Chun, Moo-Young; Kim, Kang-Min; Oh, Jae Sok; Jeong, Ueejeong; Yu, Young Sam; Lee, Jae-Joon; Kim, Hwihyun; Hwang, Narae; Lee, Sungho ^[1]; Pyo, Tae-Soo ^[2]; Kaplan, Kyle; Mace, Gregory; Jaffe, Daniel T. ^[3]; Pak, Soojong; Lee, Hye-In ^[4]

---

1. Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong-gu, Daejeon 34055 (Korea, Republic of)
2. Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences (NINS), 650 North A’ohoku Place, Hilo, HI 96720 (United States)
3. Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)
4. School of Space Research and Institute of Natural Sciences, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104 (Korea, Republic of)

We report a study of the three-dimensional (3D) outflow structure of a 15″ × 13″ area around the H{sub 2} peak 1 in Orion KL with slit-scan observations (13 slits) using the Immersion Grating Infrared Spectrograph. The datacubes have a high-velocity resolution (∼7.5 km s{sup −1}), provide high-contrast imaging within ultra-narrow bands, and enable the detection of the main stream of the previously reported H{sub 2} outflow fingers. We identified 31 distinct fingers in the H{sub 2} 1−0 S(1) λ2.122 μm emission. The line profile at each finger shows multiple-velocity peaks with a strong low-velocity component around the systemic velocity at V{sub LSR} = +8 km s{sup −1} and high-velocity emission (|V{sub LSR}| = 45–135 km s{sup −1}), indicating a typical bow-shock. The observed radial velocity gradients of ∼4 km s{sup −1} arcsec{sup −1} agree well with the velocities inferred from large-scale proper motions, where the projected motion is proportional to the distance from a common origin. We construct a conceptual 3D map of the fingers with estimated inclination angles of 57°–74°. The extinction difference (ΔA {sub v} > 10 mag) between blueshifted and redshifted fingers indicates high internal extinction. The extinction, the overall angular spread, and the scale of the flow argue for an ambient medium with a very high density (10{sup 5}–10{sup 6} cm{sup −3}), consistent with molecular line observations of the Orion Molecular Cloud core. The radial velocity gradients and the 3D distributions of the fingers together support the hypothesis of a simultaneous radial explosion of the Orion KL outflow.

• OSTI ID: 22869623
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 833; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DENSITY
DETECTION
DISTANCE
DISTRIBUTION
EMISSION
EXPLOSIONS
HYDROGEN
INCLINATION
MOLECULES
PROPER MOTION
RADIAL VELOCITY
RED SHIFT
RESOLUTION
SHOCK WAVES
STARS
STREAMS
THREE-DIMENSIONAL CALCULATIONS