Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC
High-resolution cross-correlation spectroscopy is a technique for detecting the atmospheres of close-in planets using the change in the projected planet velocity over a few hours. To date, this technique has most often been applied to hot Jupiters, which show a large change in velocity on short time...
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IOP Publishing
2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-3881/ade3c4 |
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| author | Kevin S. Hong Luke Finnerty Michael P. Fitzgerald |
| author_facet | Kevin S. Hong Luke Finnerty Michael P. Fitzgerald |
| author_sort | Kevin S. Hong |
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| description | High-resolution cross-correlation spectroscopy is a technique for detecting the atmospheres of close-in planets using the change in the projected planet velocity over a few hours. To date, this technique has most often been applied to hot Jupiters, which show a large change in velocity on short timescales. Applying this technique to planets with longer orbital periods requires an improved understanding of how the size of the velocity shift and the observational signal-to-noise ratio (SNR) impact detectability. We present grids of simulated Keck/Keck Planet Imager and Characterizer (KPIC) observations of hot Jupiter systems, varying the observed planet velocity shift and SNR, to estimate the minimum thresholds for a successful detection. These simulations realistically model the cross-correlation process, which includes a time-varying telluric spectrum in the simulated data and data detrending via principal component analysis. We test three different planet models based on an ultrahot Jupiter, a classical hot Jupiter, and a metal-rich hot Saturn. For a 6 σ detection suitable for retrieval analysis, we estimate a minimum velocity shift of Δ v _pl ∼ 30, 50, 60 km s ^−1 , compared to an instrumental resolution of 9 km s ^−1 , and minimum SNR ∼ 370, 800, 1200 for the respective planet models. We find that reported KPIC detections to-date fall above or near the 6 σ limit. These simulations can be efficiently rerun for other planet models and observational parameters, which can be useful in observation planning and detection validation. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| spelling | doaj-art-c169b588a64b4eafbd380ef8e63bd0fe2025-08-20T03:25:53ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01170211010.3847/1538-3881/ade3c4Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPICKevin S. Hong0https://orcid.org/0000-0002-1024-7627Luke Finnerty1https://orcid.org/0000-0002-1392-0768Michael P. Fitzgerald2https://orcid.org/0000-0002-0176-8973Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; kevinh29@ucla.eduDepartment of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; kevinh29@ucla.eduDepartment of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; kevinh29@ucla.eduHigh-resolution cross-correlation spectroscopy is a technique for detecting the atmospheres of close-in planets using the change in the projected planet velocity over a few hours. To date, this technique has most often been applied to hot Jupiters, which show a large change in velocity on short timescales. Applying this technique to planets with longer orbital periods requires an improved understanding of how the size of the velocity shift and the observational signal-to-noise ratio (SNR) impact detectability. We present grids of simulated Keck/Keck Planet Imager and Characterizer (KPIC) observations of hot Jupiter systems, varying the observed planet velocity shift and SNR, to estimate the minimum thresholds for a successful detection. These simulations realistically model the cross-correlation process, which includes a time-varying telluric spectrum in the simulated data and data detrending via principal component analysis. We test three different planet models based on an ultrahot Jupiter, a classical hot Jupiter, and a metal-rich hot Saturn. For a 6 σ detection suitable for retrieval analysis, we estimate a minimum velocity shift of Δ v _pl ∼ 30, 50, 60 km s ^−1 , compared to an instrumental resolution of 9 km s ^−1 , and minimum SNR ∼ 370, 800, 1200 for the respective planet models. We find that reported KPIC detections to-date fall above or near the 6 σ limit. These simulations can be efficiently rerun for other planet models and observational parameters, which can be useful in observation planning and detection validation.https://doi.org/10.3847/1538-3881/ade3c4Exoplanet atmospheresHot JupitersExoplanet atmospheric compositionHigh resolution spectroscopy |
| spellingShingle | Kevin S. Hong Luke Finnerty Michael P. Fitzgerald Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC The Astronomical Journal Exoplanet atmospheres Hot Jupiters Exoplanet atmospheric composition High resolution spectroscopy |
| title | Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC |
| title_full | Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC |
| title_fullStr | Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC |
| title_full_unstemmed | Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC |
| title_short | Velocity Shift and Signal-to-Noise Ratio Limits for High-resolution Spectroscopy of Hot Jupiters Using Keck/KPIC |
| title_sort | velocity shift and signal to noise ratio limits for high resolution spectroscopy of hot jupiters using keck kpic |
| topic | Exoplanet atmospheres Hot Jupiters Exoplanet atmospheric composition High resolution spectroscopy |
| url | https://doi.org/10.3847/1538-3881/ade3c4 |
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