Water Absorption from Gas Very Near the Massive Protostar AFGL 2136 IRS 1

Abstract

We present ground-based observations of the nu_1 and nu_3 fundamental bands of H2O toward the massive protostar AFGL 2136 IRS 1, identifying absorption features due to 47 different ro-vibrational transitions between 2.468 micron and 2.561 micron. Analysis of these features indicates the absorption arises in warm (T=506+-25 K), very dense (n(H2)>5*10^9 cm^-3) gas, suggesting an origin close to the central protostar. The total column density of warm water is estimated to be N(H2O)=(1.02+-0.02)*10^19 cm^-2, giving a relative abundance of N(H2O)/N(H2)~10^-4. Our study represents the first extensive use of water vapor absorption lines in the near infrared, and demonstrates the utility of such observations in deriving physical parameters.

17 pages, 4 figures, 1 table, accepted for publication in The Astrophysical Journal

References in corpus (3)

• H2O and OH gas in the terrestrial planet-forming zones of protoplanetary disks
• Hubble Space Telescope Survey of Interstellar ^12CO/^13CO in the Solar Neighborhood
• Direct Determination of the HF/H2 Abundance Ratio in Interstellar Gas

Cited by in corpus (5)

• Interstellar water chemistry: from laboratory to observations
• SOFIA/EXES Observations of Water Absorption in the Protostar AFGL 2591 at High Spectral Resolution
• The H${}_2$O Spectrum of the Massive Protostar AFGL 2136 IRS 1 from 2 to 13 $\mu$m at High Resolution: Probing the Circumstellar Disk
• Fundamental Vibrational Transitions of HCl Detected in CRL 2136
• Search for H${}_3^{+}$ isotopologues toward CRL 2136 IRS 1