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Upper limits to the detection of ammonia from protoplanetary disks around HL Tauri and L1551-IRS 5We present NH3(1, 1) and (2, 2) observations of the young stellar sources HL Tau and L1551-IRS 5 using the VLA in its B-configuration, which provides an angular resolution of about 0.4 arcsec (about 50 AU at 140 pc) at 1.3 cm wavelength. Our goal was to detect and resolve circumstellar molecular disks with radius of the order of 100 AU around these two sources. No ammonia emission was detected toward either of them. The 3-sigma levels were 2.7 mJy/beam and 3.9 mJy/beam for HL Tau and L1551-IRS 5, respectively, with a velocity resolution of about 5 km/s. With this nondetection, we estimate upper limits to the mass of the proposed protoplanetary molecular disks (within a radius of 10 AU from the central stars) on the order of 0.02/(X(NH3)/10 exp -8) solar mass for HL Tau and 0.1/(X(NH3)/10 exp -8) solar mass for L1551-IRS 5.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Gomez, Jose F.
(NASA Headquarters Washington, DC United States)
Torrelles, Jose M.
(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA; Andalucia, Inst. de Astrofisica Granada, Spain)
Ho, Paul T. P.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Rodriguez, Luis F.
(NASA Headquarters Washington, DC United States)
Canto, Jorge
(Univ. Nacional Autonoma de Mexico Coyoacan, United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 414
Issue: 1
ISSN: 0004-637X
Subject Category
Accession Number
Funding Number(s)
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