Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-25T19:02:25.007Z Has data issue: false hasContentIssue false

Possibility to locate the position of the H2O snowline in protoplanetary disks through spectroscopic observations

Published online by Cambridge University Press:  04 September 2018

Shota Notsu
Affiliation:
Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan e-mail: snotsu@kusastro.kyoto-u.ac.jp Research Fellow of Japan Society for the Promotion of Science (DC1)
Hideko Nomura
Affiliation:
Department of Earth and Planetary Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
Catherine Walsh
Affiliation:
School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
Mitsuhiko Honda
Affiliation:
Department of Physics, School of Medicine, Kurume University, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
Tomoya Hirota
Affiliation:
National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
Eiji Akiyama
Affiliation:
National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
T. J. Millar
Affiliation:
Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, University Road, Belfast, BT7 1NN, UK
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Observationally measuring the location of the H2O snowline is crucial for understanding the planetesimal and planet formation processes, and the origin of water on Earth. The velocity profiles of emission lines from protoplanetary disks are usually affected by Doppler shift due to Keplerian rotation and thermal broadening. Therefore, the velocity profiles are sensitive to the radial distribution of the line-emitting regions. In our work (Notsu et al. 2016, 2017), we found candidate water lines to locate the position of the H2O snowline through future high-dispersion spectroscopic observations. First, we calculated the chemical composition of the disks around a T Tauri star and a Herbig Ae star using chemical kinetics. We confirmed that the abundance of H2O gas is high not only in the hot midplane region inside the H2O snowline but also in the hot surface layer and the photodesorption region of the outer disk. The position of the H2O snowline in the Herbig Ae disk exists at a larger radius from the central star than that in the T Tauri disk. Second, we calculated the H2O line profiles and identified that H2O emission lines with small Einstein A coefficients (∼10−6 − 10−3 s−1) and relatively high upper state energies (∼ 1000K) are dominated by emission from the hot midplane region inside the H2O snowline, and therefore their profiles potentially contain information which can be used to locate the position of the H2O snowline. The wavelengths of the H2O lines which are the best candidates to locate the position of the H2O snowline range from mid-infrared to sub-millimeter, and the total line fluxes tend to increase with decreasing wavelengths. We investigated the possibility of future observations using the ALMA and mid-infrared high-dispersion spectrographs (e.g., SPICA/SMI-HRS). Since the fluxes of those identified lines from a Herbig Ae disk are stronger than those of a T Tauri disk, the possibility of a successful detection is expected to increase for a Herbig Ae disk.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2018 

References

Banzatti, A., Pontoppidan, K. M., Salyk, C., et al. 2017, ApJ, 834, 152Google Scholar
Blevins, S. M., Pontoppidan, K. M., Banzatti, A., et al. 2016, ApJ, 818, 22Google Scholar
Eistrup, C., Walsh, C., & van Dishoeck, E. F., 2016, A&A, 595, A83Google Scholar
Furuya, K., Aikawa, Y., Nomura, H., Hersant, F., & Wakelam, V., 2013, ApJ, 779, 11Google Scholar
Graedel, T. E., Langer, W. D., & Frerking, M. A., 1982, ApJS, 48, 321Google Scholar
Hayashi, C., 1981, Progress of Theoretical Physics Supplement, 70, 35Google Scholar
Hayashi, C., Nakazawa, K., & Nakagawa, Y. 1985, Protostars and Planets II, University of Arizona Press, 1100Google Scholar
Heinzeller, D., Nomura, H., Walsh, C., & Millar, T. J., 2011, ApJ, 731, 115Google Scholar
Hogerheijde, M. R., Bergin, E. A., Brinch, C., et al. 2011, Science, 334, 338Google Scholar
Hogerheijde, M. R. & van der Tak, F. F. S., 2000, A&A, 362, 697Google Scholar
Morbidelli, A., Bitsch, B., Crida, A., et al. 2016, Icarus, 267, 368Google Scholar
Morbidelli, A., Chambers, J., Lunine, J. I., et al. 2000, Meteoritics and Planetary Science, 35, 1309Google Scholar
Morbidelli, A., Lunine, J. I., O’Brien, D. P., Raymond, S. N., & Walsh, K. J., 2012, Annual Review of Earth and Planetary Sciences, 40, 251Google Scholar
Nomura, H. & Millar, T. J., 2005, A&A, 438, 923Google Scholar
Nomura, H., Aikawa, Y., Tsujimoto, M., Nakagawa, Y., & Millar, T. J., 2007, ApJ, 661, 334Google Scholar
Notsu, S., Nomura, H., Ishimoto, D., Walsh, C., Honda, M., Hirota, T., & Millar, T. J., 2017a, ApJ, 836, 118Google Scholar
Notsu, S., Nomura, H., Ishimoto, D., Walsh, C., Honda, M., Hirota, T., & Millar, T. J., 2016, ApJ, 827, 113Google Scholar
Notsu, S., Nomura, H., Ishimoto, D., et al. 2015, Revolution in Astronomy with ALMA: The Third Year, ASP Conference Series, 499, 289Google Scholar
Öberg, K. I., Murray-Clay, R., & Bergin, E. A., 2011, ApJ, 743, L16Google Scholar
Oka, A., Nakamoto, T., & Ida, S., 2011, ApJ, 738, 141Google Scholar
Okuzumi, S., Tanaka, H., Kobayashi, H., & Wada, K., 2012, ApJ, 752, 106Google Scholar
Piso, A.-M. A., Öberg, K. I., Birnstiel, T., & Murray-Clay, R. A., 2015, ApJ, 815, 109Google Scholar
Podio, L., Kamp, I., Codella, C., et al. 2013, ApJ, 766, L5Google Scholar
Pontoppidan, K. M., Salyk, C., Blake, G. A., et al. 2010a, ApJ, 720, 887Google Scholar
Pontoppidan, K. M., Salyk, C., Blake, G. A., K&aumlufl, H. U., 2010b, ApJ, 722, L173Google Scholar
Ros, K. & Johansen, A., 2013, A&A, 552, A137Google Scholar
Rybicki, G. B. & Lightman, A. P. 1986, Radiative Processes in Astrophysics, by George B. Rybicki, Alan P. Lightman, pp. 400. ISBN 0-471-82759-2. Wiley-VCH, June 1986Google Scholar
Sato, T., Okuzumi, S., & Ida, S., 2016, A&A, 589, A15Google Scholar
Schöier, F. L., van der Tak, F. F. S., van Dishoeck, E. F., & Black, J. H., 2005, A&A, 432, 369Google Scholar
van Dishoeck, E. F., Bergin, E. A., Lis, D. C., & Lunine, J. I. 2014, Protostars and Planets VI, University of Arizona Press, 835Google Scholar
Walsh, C., Millar, T. J., & Nomura, H., 2010, ApJ, 722, 1607Google Scholar
Walsh, C., Millar, T. J., Nomura, H., et al. 2014a, A&A, 563, AA33Google Scholar
Walsh, C., Nomura, H., Millar, T. J., & Aikawa, Y., 2012, ApJ, 747, 114Google Scholar
Walsh, C., Nomura, H., & van Dishoeck, E., 2015, A&A, 582, A88Google Scholar
Woitke, P., Thi, W.-F., Kamp, I., & Hogerheijde, M. R., 2009b, A&A, 501, L5Google Scholar
Woodall, J., Agúndez, M., Markwick-Kemper, A. J., & Millar, T. J., 2007, A&A, 466, 1197Google Scholar