# UPPER LIMITS TO THE DETECTION OF AMMONIA FROM PROTOPLANETARY DISKS AROUND HL TAURI AND L1551-IRS 5

DOI:
10.1086/173079
Publication date:
01/09/1993
Main author:
GOMEZ, JF
IAA authors:
Authors:
GOMEZ, JF; TORRELLES, JM; HO, PTP; RODRIGUEZ, LF; CANTO, J
Journal:
ASTROPHYSICAL JOURNAL
Publication type:
Article
Volume:
414
Pages:
333-336
Number:
Abstract:
We 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 approximately 0.4'' (approximately 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-1 and 3.9 mJy beam-1 for HL Tau and L1551-IRS 5, respectively, with a velocity resolution of approximately 5 km s-1. 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(-8))-1 M. for HL Tau and 0.1 (X(NH3)/10(-8))-1 M. for L1551-IRS 5.
Database:
WOK
Keywords:
CIRCUMSTELLAR MATTER; STARS, INDIVIDUAL (HL TAURI, L1551 IRS 5); STARS, PRE-MAIN-SEQUENCE