ALMA BAND 8 CONTINUUM EMISSION FROM ORION SOURCE I

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

DOI:https://doi.org/10.3847/1538-4357/833/2/238· OSTI ID:22661457

Hirota, Tomoya; Matsumoto, Naoko ^[1]; Machida, Masahiro N.; Matsushita, Yuko ^[2]; Motogi, Kazuhito; Honma, Mareki ^[3]; Kim, Mi Kyoung ^[4]

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1. Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka-shi, Tokyo 181-8588 (Japan)
2. Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Motooka 744, Nishi-ku, Fukuoka-shi, Fukuoka 819-0395 (Japan)
3. Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, Hoshigaoka2-12, Mizusawa-ku, Oshu-shi, Iwate 023-0861 (Japan)
4. Korea Astronomy and Space Science Institute, Hwaam-dong 61-1, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of)

We have measured continuum flux densities of a high-mass protostar candidate, a radio source I in the Orion KL region (Orion Source I) using the Atacama Large Millimeter/Submillimeter Array (ALMA) at band 8 with an angular resolution of 0.″1. The continuum emission at 430, 460, and 490 GHz associated with Source I shows an elongated structure along the northwest–southeast direction perpendicular to the so-called low-velocity bipolar outflow. The deconvolved size of the continuum source, 90 au × 20 au, is consistent with those reported previously at other millimeter/submillimeter wavelengths. The flux density can be well fitted to the optically thick blackbody spectral energy distribution, and the brightness temperature is evaluated to be 700–800 K. It is much lower than that in the case of proton–electron or H{sup −} free–free radiations. Our data are consistent with the latest ALMA results by Plambeck and Wright, in which the continuum emission was proposed to arise from the edge-on circumstellar disk via thermal dust emission, unless the continuum source consists of an unresolved structure with a smaller beam filling factor.

• OSTI ID: 22661457
• 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
BRIGHTNESS
COSMIC DUST
ELECTRONS
EMISSION
ENERGY SPECTRA
FLUX DENSITY
GHZ RANGE
HYDROGEN IONS 1 MINUS
MASS
PROTONS
PROTOSTARS
RESOLUTION
STARS
VELOCITY
WAVELENGTHS