The observations show that there is at least three times more water in the inner disc of the young Sun-like star HL Tauri than in all of Earth’s oceans combined.
HL Tau also called HL Tauri is a young T Tauri star located approximately 450 light-years away from earth in the Taurus Molecular Cloud. It is surrounded by a protoplanetary disk that exhibits a series of concentric bright rings separated by gaps, as revealed by high-resolution observations from the Atacama Large Millimeter/submillimeter Array (ALMA).
Location of HL Tau in the Taurus Molecular Cloud
https://twitter.com/universal_sci/status/1762962965446180910
Taurus Molecular Cloud Gas Dynamics:
Protoplanetary Disk Structure
The striking ring-like structures observed in the HL Tau disk are believed to be indicators of ongoing planet formation processes. The gaps in the disk may be carved out by forming planets, while the bright rings could be regions of higher dust density where planet formation is occurring. The presence of these features suggests that planet formation may happen more rapidly than previously thought, as the HL Tau system is estimated to be less than 100,000 years old.
Disk Properties and Modeling
Detailed radiative transfer modeling of the dust emission from the HL Tau disk has been conducted to derive its surface density profile and structure. The modeling results indicate a radial gradient in the dust grain size distribution, with larger grains present in the inner disk regions.
Theoretical studies have explored the possibility of planet formation in the HL Tau disk, considering various planet trapping mechanisms and disk models with different initial masses. These simulations suggest that the prominent gaps and rings observed in the disk could indeed be associated with the formation of planets, particularly at the locations of volatile ice lines.
Water detected with ALMA
Three times more water than the Earth’s oceans!
Outflows and Jets
In addition to the protoplanetary disk, HL Tau is also known to exhibit bipolar outflows and jets of gas, such as the Herbig-Haro object HH 150. These outflows are emitted along the rotational axis of the disk and interact with the surrounding interstellar material, producing observable features.
Overall, the HL Tau system provides a unique opportunity to study the early stages of planet formation and the evolution of protoplanetary disks, thanks to the detailed observations and modeling efforts enabled by advanced telescopes like ALMA.
References:
The properties of the inner disk around HL Tau: Multi-wavelength modeling of the dust emission
Yao Liu, Thomas Henning, Carlos Carrasco-González, Claire J. Chandler, Hendrik Linz, Til Birnstiel, Roy van Boekel, Laura M. Pérez, Mario Flock, Leonardo Testi, Luis F. Rodríguez and Roberto Galván-Madrid
| Issue | A&AVolume 607, November 2017 |
|---|---|
| Article Number | A74 |
| Number of page(s) | 10 |
| Section | Interstellar and circumstellar matter |
| DOI | https://doi.org/10.1051/0004-6361/201629786 |
| Published online | 16 November 2017 |
https://www.aanda.org/articles/aa/full_html/2017/11/aa29786-16/aa29786-16.html
Physics of planet trapping with applications to HL Tau
Alexander J Cridland, Ralph E Pudritz, Matthew Alessi
Monthly Notices of the Royal Astronomical Society, Volume 484, Issue 1, March 2019, Pages 345–363, https://doi.org/10.1093/mnras/stz008
Published: 05 January 2019
https://academic.oup.com/mnras/article/484/1/345/5274147
On planet formation in HL Tau
Giovanni Dipierro, Daniel Price, Guillaume Laibe, Kieran Hirsh, Alice Cerioli, Giuseppe Lodato
https://academic.oup.com/mnrasl/article/453/1/L73/983336
Astronomers reveal a new link between water and planet formation
Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk
Stefano Facchini, Leonardo Testi, Elizabeth Humphreys, Mathieu Vander Donckt, Andrea Isella, Ramon Wrzosek, Alain Baudry, Malcom D. Gray,
Anita M. S. Richards & Wouter Vlemmmings
https://www.nature.com/articles/s41550-024-02207-w
Circular Astronomy 