Hunting for methanol in the water rich, planet forming disk around HL Tau
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866911628864258048 |
|---|---|
| author | Soave, Alessandro Leemker, Margot Facchini, Stefano Maud, Luke Rygl, Kazi Lucie Jessica Testi, Leonardo |
| author_facet | Soave, Alessandro Leemker, Margot Facchini, Stefano Maud, Luke Rygl, Kazi Lucie Jessica Testi, Leonardo |
| contents | Methanol, the simplest complex organic molecule found in space, is considered a key compound necessary for the formation of chemical species of prebiotic interest. Methanol detections in protoplanetary disks remain scarce, even though it is frequently detected in the material surrounding other Young Stellar Objects. We investigate the presence of methanol in the protoplanetary disk around the HL Tau protostar, motivated by the detection of spatially resolved warm water emission. Given the similar volatility of methanol and water, thermally desorbed gas-phase methanol is expected to emit from the same region of the HL Tau disk where water vapour has been observed. Accordingly, we selected and imaged the most promising ALMA archival observations to search for rotational methanol lines. We found no methanol emission in the analysed archival datasets. Assuming optically thin emission and LTE, we derive stringent upper limits on the methanol column density for different excitation temperatures: < 7.2 x 10^(14) cm^(-2) at 100 K and < 1.8 x 10^(15) cm^(-2) at 200 K, assuming a circular emitting region with a radius of 17 au (~ 0.12''). Furthermore, we obtain a stringent upper limit on the methanol-to-water column density ratio (< 0.55 x 10^(-3) at 100 K and < 1.4x 10^(-3) at 200 K), which is, on average, an order of magnitude lower than the values measured for other Young Stellar Objects and Solar System comets. We argue that the most likely explanation for the methanol non-detection in HL Tau is the presence of optically thick dust in the central region of the disk, which obscures part of the methanol emission. The upper limit on the methanol-to-water ratio in the HL Tau disk is at least an order of magnitude smaller than most clouds, YSOs and comets, possibly due to radiative transfer and/or excitation effects, or due to a different chemical evolution compared to the other sources. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_04322 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Hunting for methanol in the water rich, planet forming disk around HL Tau Soave, Alessandro Leemker, Margot Facchini, Stefano Maud, Luke Rygl, Kazi Lucie Jessica Testi, Leonardo Solar and Stellar Astrophysics Earth and Planetary Astrophysics Methanol, the simplest complex organic molecule found in space, is considered a key compound necessary for the formation of chemical species of prebiotic interest. Methanol detections in protoplanetary disks remain scarce, even though it is frequently detected in the material surrounding other Young Stellar Objects. We investigate the presence of methanol in the protoplanetary disk around the HL Tau protostar, motivated by the detection of spatially resolved warm water emission. Given the similar volatility of methanol and water, thermally desorbed gas-phase methanol is expected to emit from the same region of the HL Tau disk where water vapour has been observed. Accordingly, we selected and imaged the most promising ALMA archival observations to search for rotational methanol lines. We found no methanol emission in the analysed archival datasets. Assuming optically thin emission and LTE, we derive stringent upper limits on the methanol column density for different excitation temperatures: < 7.2 x 10^(14) cm^(-2) at 100 K and < 1.8 x 10^(15) cm^(-2) at 200 K, assuming a circular emitting region with a radius of 17 au (~ 0.12''). Furthermore, we obtain a stringent upper limit on the methanol-to-water column density ratio (< 0.55 x 10^(-3) at 100 K and < 1.4x 10^(-3) at 200 K), which is, on average, an order of magnitude lower than the values measured for other Young Stellar Objects and Solar System comets. We argue that the most likely explanation for the methanol non-detection in HL Tau is the presence of optically thick dust in the central region of the disk, which obscures part of the methanol emission. The upper limit on the methanol-to-water ratio in the HL Tau disk is at least an order of magnitude smaller than most clouds, YSOs and comets, possibly due to radiative transfer and/or excitation effects, or due to a different chemical evolution compared to the other sources. |
| title | Hunting for methanol in the water rich, planet forming disk around HL Tau |
| topic | Solar and Stellar Astrophysics Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2603.04322 |