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Possibility to locate the position of the H2O snowline in protoplanetary disks through spectroscopic observations
| Content Provider | Scilit |
|---|---|
| Author | Notsu, Shota Nomura, Hideko Walsh, Catherine Honda, Mitsuhiko Hirota, Tomoya Akiyama, Eiji Millar, T. J. |
| Copyright Year | 2017 |
| Abstract | Observationally measuring the location of the $H_{2}$O 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 $H_{2}$O 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 $H_{2}$O gas is high not only in the hot midplane region inside the $H_{2}$O snowline but also in the hot surface layer and the photodesorption region of the outer disk. The position of the $H_{2}$O 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 $H_{2}$O line profiles and identified that $H_{2}$O 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 $H_{2}$O snowline, and therefore their profiles potentially contain information which can be used to locate the position of the $H_{2}$O snowline. The wavelengths of the $H_{2}$O lines which are the best candidates to locate the position of the $H_{2}$O 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. |
| Related Links | https://www.cambridge.org/core/services/aop-cambridge-core/content/view/442D2455417FBC3E328927AEEC250C0A/S1743921317007797a.pdf/div-class-title-possibility-to-locate-the-position-of-the-h-span-class-sub-2-span-o-snowline-in-protoplanetary-disks-through-spectroscopic-observations-div.pdf |
| Ending Page | 120 |
| Page Count | 8 |
| Starting Page | 113 |
| ISSN | 17439213 |
| e-ISSN | 17439221 |
| DOI | 10.1017/s1743921317007797 |
| Journal | Proceedings of the International Astronomical Union |
| Issue Number | S332 |
| Volume Number | 13 |
| Language | English |
| Publisher | Cambridge University Press (CUP) |
| Publisher Date | 2017-03-01 |
| Access Restriction | Open |
| Subject Keyword | Proceedings of the International Astronomical Union Astronomy and Astrophysics Emission Lines High Dispersion Locate the Position |
| Content Type | Text |
| Resource Type | Article |
| Subject | Astronomy and Astrophysics Space and Planetary Science |
