Tracing the formation and migration history: molecular signatures in the atmosphere of misaligned hot Jupiter WASP-94Ab using JWST NIRSpec/G395H
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866916780205670400 |
|---|---|
| author | Ahrer, Eva-Maria Gandhi, Siddharth Alderson, Lili Kirk, James Teske, Johanna Booth, Richard A. McDonald, Catriona H. Christie, Duncan A. Claringbold, Alastair B. Nealon, Rebecca Panwar, Vatsal Veras, Dimitri Wakeford, Hannah R. Wheatley, Peter J. Zamyatina, Maria |
| author_facet | Ahrer, Eva-Maria Gandhi, Siddharth Alderson, Lili Kirk, James Teske, Johanna Booth, Richard A. McDonald, Catriona H. Christie, Duncan A. Claringbold, Alastair B. Nealon, Rebecca Panwar, Vatsal Veras, Dimitri Wakeford, Hannah R. Wheatley, Peter J. Zamyatina, Maria |
| contents | The discovery of hot Jupiters that orbit very close to their host stars has long challenged traditional models of planetary formation and migration. Characterising their atmospheric composition - mainly in the form of the carbon-to-oxygen (C/O) ratio and metallicity - can provide insights into their formation locations and evolution pathways. With JWST we can characterise the atmospheres of these types of planets more precisely than previously possible, primarily because it allows us to determine both their atmospheric oxygen and carbon composition. Here, we present a JWST NIRSpec/G395H transmission spectrum from 2.8-5.1$μm$ of WASP-94Ab, an inflated hot Jupiter with a retrograde misaligned orbit around its F-type host star. We find a relatively cloud-free atmosphere, with absorption features of H$_2$O and CO$_2$ at detection significances of $\sim 4σ$ and $\sim 11σ$, respectively. In addition, we detect tentative evidence of CO absorption at $\sim3σ$, as well as hints of sulphur with the detection of H$_2$S at a $\sim 2.5σ$ confidence level. Our favoured equilibrium chemistry model determines a C/O ratio of $0.49^{+0.08}_{-0.13}$ for WASP-94Ab's atmosphere, which is substellar compared to the star's C/O ratio of $0.68 \pm 0.10$. The retrieved atmospheric metallicity is similar to the star's metallicity as both are $\sim 2\times$ solar. We find that this sub-stellar C/O ratio and stellar metallicity can be best explained by pebble accretion or planetesimal accretion in combination with large-distance migration of the planet. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_11224 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Tracing the formation and migration history: molecular signatures in the atmosphere of misaligned hot Jupiter WASP-94Ab using JWST NIRSpec/G395H Ahrer, Eva-Maria Gandhi, Siddharth Alderson, Lili Kirk, James Teske, Johanna Booth, Richard A. McDonald, Catriona H. Christie, Duncan A. Claringbold, Alastair B. Nealon, Rebecca Panwar, Vatsal Veras, Dimitri Wakeford, Hannah R. Wheatley, Peter J. Zamyatina, Maria Earth and Planetary Astrophysics The discovery of hot Jupiters that orbit very close to their host stars has long challenged traditional models of planetary formation and migration. Characterising their atmospheric composition - mainly in the form of the carbon-to-oxygen (C/O) ratio and metallicity - can provide insights into their formation locations and evolution pathways. With JWST we can characterise the atmospheres of these types of planets more precisely than previously possible, primarily because it allows us to determine both their atmospheric oxygen and carbon composition. Here, we present a JWST NIRSpec/G395H transmission spectrum from 2.8-5.1$μm$ of WASP-94Ab, an inflated hot Jupiter with a retrograde misaligned orbit around its F-type host star. We find a relatively cloud-free atmosphere, with absorption features of H$_2$O and CO$_2$ at detection significances of $\sim 4σ$ and $\sim 11σ$, respectively. In addition, we detect tentative evidence of CO absorption at $\sim3σ$, as well as hints of sulphur with the detection of H$_2$S at a $\sim 2.5σ$ confidence level. Our favoured equilibrium chemistry model determines a C/O ratio of $0.49^{+0.08}_{-0.13}$ for WASP-94Ab's atmosphere, which is substellar compared to the star's C/O ratio of $0.68 \pm 0.10$. The retrieved atmospheric metallicity is similar to the star's metallicity as both are $\sim 2\times$ solar. We find that this sub-stellar C/O ratio and stellar metallicity can be best explained by pebble accretion or planetesimal accretion in combination with large-distance migration of the planet. |
| title | Tracing the formation and migration history: molecular signatures in the atmosphere of misaligned hot Jupiter WASP-94Ab using JWST NIRSpec/G395H |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2505.11224 |