A KEPLERIAN CIRCUMBINARY DISK AROUND THE PROTOSTELLAR SYSTEM L1551 NE
- Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)
- ALMA Project Office, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)
- Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong)
We present Submillimeter Array observations of a Keplerian disk around the Class I protobinary system L1551 NE in 335 GHz continuum emission and submillimeter line emission in {sup 13}CO (J = 3-2) and C{sup 18}O (J = 3-2) at a resolution of {approx}120 Multiplication-Sign 80 AU. The 335 GHz dust-continuum image shows a strong central peak closely coincident with the binary protostars and likely corresponding to circumstellar disks, surrounded by a {approx}600 Multiplication-Sign 300 AU feature elongated approximately perpendicular to the [Fe II] jet from the southern protostellar component suggestive of a circumbinary disk. The {sup 13}CO and C{sup 18}O images confirm that the circumbinary continuum feature is indeed a rotating disk; furthermore, the C{sup 18}O channel maps can be well modeled by a geometrically thin disk exhibiting Keplerian rotation. We estimate a mass for the circumbinary disk of {approx}0.03-0.12 M{sub Sun }, compared with an enclosed mass of {approx}0.8 M{sub Sun} that is dominated by the protobinary system. Compared with several other Class I protostars known to exhibit Keplerian disks, L1551 NE has the lowest bolometric temperature ({approx}91 K), highest envelope mass ({approx}0.39 M{sub Sun }), and the lowest ratio in stellar mass to envelope + disk + stellar mass ({approx}0.65). L1551 NE may therefore be the youngest protostellar object so far found to exhibit a Keplerian disk. Our observations present firm evidence that Keplerian disks around binary protostellar systems, 'Keplerian circumbinary disks', can exist. We speculate that tidal effects from binary companions could transport angular momenta toward the inner edge of the circumbinary disk and create the Keplerian circumbinary disk.
- OSTI ID:
- 22039297
- Journal Information:
- Astrophysical Journal, Vol. 754, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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