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Title: Candidate Water Vapor Lines to Locate the H{sub 2}O Snowline Through High-dispersion Spectroscopic Observations. II. The Case of a Herbig Ae Star

Abstract

Observationally measuring the location of the H{sub 2}O snowline is crucial for understanding planetesimal and planet formation processes, and the origin of water on Earth. In disks around Herbig Ae stars (T {sub *} ∼ 10,000 K, M {sub *} ≳ 2.5M {sub ⊙}), the position of the H{sub 2}O snowline is farther from the central star compared with that around cooler and less massive T Tauri stars. Thus, the H{sub 2}O emission line fluxes from the region within the H{sub 2}O snowline are expected to be stronger. In this paper, we calculate the chemical composition of a Herbig Ae disk using chemical kinetics. Next, we calculate the H{sub 2}O emission line profiles and investigate the properties of candidate water lines across a wide range of wavelengths (from mid-infrared to submillimeter) that can locate the position of the H{sub 2}O snowline. Those lines identified have small Einstein A coefficients (∼10{sup −6}--10{sup −3} s{sup −1}) and relatively high upper-state energies (∼1000 K). The total fluxes tend to increase with decreasing wavelengths. We investigate the possibility of future observations (e.g., ALMA, SPICA/SMI-HRS) locating the position of the H{sub 2}O snowline. Since the fluxes of those identified lines from Herbig Ae disks are stronger than those frommore » T Tauri disks, the possibility of a successful detection is expected to increase for a Herbig Ae disk.« less

Authors:
;  [1];  [2];  [3];  [4];  [5]
  1. Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)
  2. Department of Earth and Planetary Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)
  3. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  4. Department of Physics, School of Medicine, Kurume University, 67 Asahi-machi, Kurume, Fukuoka 830-0011 (Japan)
  5. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
Publication Date:
OSTI Identifier:
22869355
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 836; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; DETECTION; DISPERSIONS; EMISSION; MOLECULES; PLANETS; PROTOPLANETS; STAR EVOLUTION; T TAURI STARS; WATER VAPOR

Citation Formats

Notsu, Shota, Ishimoto, Daiki, Nomura, Hideko, Walsh, Catherine, Honda, Mitsuhiko, Hirota, Tomoya, and Millar, T. J., E-mail: snotsu@kusastro.kyoto-u.ac.jp. Candidate Water Vapor Lines to Locate the H{sub 2}O Snowline Through High-dispersion Spectroscopic Observations. II. The Case of a Herbig Ae Star. United States: N. p., 2017. Web. doi:10.3847/1538-4357/836/1/118.
Notsu, Shota, Ishimoto, Daiki, Nomura, Hideko, Walsh, Catherine, Honda, Mitsuhiko, Hirota, Tomoya, & Millar, T. J., E-mail: snotsu@kusastro.kyoto-u.ac.jp. Candidate Water Vapor Lines to Locate the H{sub 2}O Snowline Through High-dispersion Spectroscopic Observations. II. The Case of a Herbig Ae Star. United States. https://doi.org/10.3847/1538-4357/836/1/118
Notsu, Shota, Ishimoto, Daiki, Nomura, Hideko, Walsh, Catherine, Honda, Mitsuhiko, Hirota, Tomoya, and Millar, T. J., E-mail: snotsu@kusastro.kyoto-u.ac.jp. 2017. "Candidate Water Vapor Lines to Locate the H{sub 2}O Snowline Through High-dispersion Spectroscopic Observations. II. The Case of a Herbig Ae Star". United States. https://doi.org/10.3847/1538-4357/836/1/118.
@article{osti_22869355,
title = {Candidate Water Vapor Lines to Locate the H{sub 2}O Snowline Through High-dispersion Spectroscopic Observations. II. The Case of a Herbig Ae Star},
author = {Notsu, Shota and Ishimoto, Daiki and Nomura, Hideko and Walsh, Catherine and Honda, Mitsuhiko and Hirota, Tomoya and Millar, T. J., E-mail: snotsu@kusastro.kyoto-u.ac.jp},
abstractNote = {Observationally measuring the location of the H{sub 2}O snowline is crucial for understanding planetesimal and planet formation processes, and the origin of water on Earth. In disks around Herbig Ae stars (T {sub *} ∼ 10,000 K, M {sub *} ≳ 2.5M {sub ⊙}), the position of the H{sub 2}O snowline is farther from the central star compared with that around cooler and less massive T Tauri stars. Thus, the H{sub 2}O emission line fluxes from the region within the H{sub 2}O snowline are expected to be stronger. In this paper, we calculate the chemical composition of a Herbig Ae disk using chemical kinetics. Next, we calculate the H{sub 2}O emission line profiles and investigate the properties of candidate water lines across a wide range of wavelengths (from mid-infrared to submillimeter) that can locate the position of the H{sub 2}O snowline. Those lines identified have small Einstein A coefficients (∼10{sup −6}--10{sup −3} s{sup −1}) and relatively high upper-state energies (∼1000 K). The total fluxes tend to increase with decreasing wavelengths. We investigate the possibility of future observations (e.g., ALMA, SPICA/SMI-HRS) locating the position of the H{sub 2}O snowline. Since the fluxes of those identified lines from Herbig Ae disks are stronger than those from T Tauri disks, the possibility of a successful detection is expected to increase for a Herbig Ae disk.},
doi = {10.3847/1538-4357/836/1/118},
url = {https://www.osti.gov/biblio/22869355}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 836,
place = {United States},
year = {2017},
month = {2}
}