Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2503.07719 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866911281638801408 |
|---|---|
| author | Lenhart, Calder Johnson, Marshall C. Wang, Ji Asnodkar, Anusha Pai Petz, Sydney Duck, Alison Strassmeier, Klaus G. Ilyin, Ilya |
| author_facet | Lenhart, Calder Johnson, Marshall C. Wang, Ji Asnodkar, Anusha Pai Petz, Sydney Duck, Alison Strassmeier, Klaus G. Ilyin, Ilya |
| contents | KELT-20b is a well-studied ($T_{\text{eq}}=2262$ K) ultra hot Jupiter, but its multidimensional atmospheric structure remains unconstrained. We performed high-resolution cross-correlation transmission spectroscopy (HRCCTS) on a single transit time series of KELT-20b, observed with PEPSI on the LBT. Upon combining nineteen in-transit exposures, we detect Fe I $(11.9σ)$ and Fe II $(23.7σ)$ and tentatively detect Na I $(3.4σ)$ and Cr I $(3.3σ)$. The full-transit velocity offsets of the strongest absorbers are $ΔV_{\text{Fe I}} = -1.0 \pm 0.7$ km s$^{-1}$ and $ΔV_{\text{Fe II}}= 0.0\pm 0.5$ km s$^{-1}$, which are mostly inconsistent with previously published values for KELT-20b, although the previous measurements are mostly inconsistent with each other. By correcting for discrepant systemic velocity solutions of up to $1.7$ km s$^{-1}$ between studies, our Fe II offset becomes consistent with previous measurements ($\leq 1.7σ$), while Fe I remains significantly less blueshifted than in earlier studies ($ \geq 2.2-4.5σ$). We propose a set of detection criteria to improve future reproducibility in HRCCTS work. Phase-resolving the Fe I and Fe II absorption signatures into eight orbital phase bins reveals distinct dynamical regimes: Fe II exhibits a strong phase-dependent blueshift from ingress to egress along with significant limb asymmetry, while Fe I shows weaker signals and a more modest blueshift with phase. These patterns indicate day-to-night winds and suggest scale height differences are a significant driver of limb asymmetry in KELT-20b. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_07719 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). II. Phase-Resolved Cross-Correlation Transmission Spectroscopy of KELT-20b Lenhart, Calder Johnson, Marshall C. Wang, Ji Asnodkar, Anusha Pai Petz, Sydney Duck, Alison Strassmeier, Klaus G. Ilyin, Ilya Earth and Planetary Astrophysics KELT-20b is a well-studied ($T_{\text{eq}}=2262$ K) ultra hot Jupiter, but its multidimensional atmospheric structure remains unconstrained. We performed high-resolution cross-correlation transmission spectroscopy (HRCCTS) on a single transit time series of KELT-20b, observed with PEPSI on the LBT. Upon combining nineteen in-transit exposures, we detect Fe I $(11.9σ)$ and Fe II $(23.7σ)$ and tentatively detect Na I $(3.4σ)$ and Cr I $(3.3σ)$. The full-transit velocity offsets of the strongest absorbers are $ΔV_{\text{Fe I}} = -1.0 \pm 0.7$ km s$^{-1}$ and $ΔV_{\text{Fe II}}= 0.0\pm 0.5$ km s$^{-1}$, which are mostly inconsistent with previously published values for KELT-20b, although the previous measurements are mostly inconsistent with each other. By correcting for discrepant systemic velocity solutions of up to $1.7$ km s$^{-1}$ between studies, our Fe II offset becomes consistent with previous measurements ($\leq 1.7σ$), while Fe I remains significantly less blueshifted than in earlier studies ($ \geq 2.2-4.5σ$). We propose a set of detection criteria to improve future reproducibility in HRCCTS work. Phase-resolving the Fe I and Fe II absorption signatures into eight orbital phase bins reveals distinct dynamical regimes: Fe II exhibits a strong phase-dependent blueshift from ingress to egress along with significant limb asymmetry, while Fe I shows weaker signals and a more modest blueshift with phase. These patterns indicate day-to-night winds and suggest scale height differences are a significant driver of limb asymmetry in KELT-20b. |
| title | PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). II. Phase-Resolved Cross-Correlation Transmission Spectroscopy of KELT-20b |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2503.07719 |