A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination
We present a population study of 20 exoplanets, ranging from Neptune-like to inflated hot-Jupiter planets, observed during transit with the Space Telescope Imaging Spectrograph (STIS) and Wide Field Camera 3 (WFC3) instruments on board the Hubble Space Telescope (HST). To obtain spectral information...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4365/ad8c3c |
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| author | Arianna Saba Alexandra Thompson Kai Hou Yip Sushuang Ma Angelos Tsiaras Ahmed Faris Al-Refaie Giovanna Tinetti |
| author_facet | Arianna Saba Alexandra Thompson Kai Hou Yip Sushuang Ma Angelos Tsiaras Ahmed Faris Al-Refaie Giovanna Tinetti |
| author_sort | Arianna Saba |
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| description | We present a population study of 20 exoplanets, ranging from Neptune-like to inflated hot-Jupiter planets, observed during transit with the Space Telescope Imaging Spectrograph (STIS) and Wide Field Camera 3 (WFC3) instruments on board the Hubble Space Telescope (HST). To obtain spectral information from the near-ultraviolet to the near-infrared, we reanalyzed 16 WFC3 and over 50 STIS archival data sets with our dedicated HST pipeline. We also include 24 WFC3 data sets previously reduced with the same software. Across our target sample, we observe significant divergence among multiple observations conducted with the same STIS grating at various epochs, while we do not detect variations in the WFC3 data sets. These results are suggestive of stellar contamination, which we have investigated further using known Bayesian tools and other tailored metrics, facilitating a more objective assessment of stellar activity intensity within each system. Our findings reveal that stellar activity contaminates up to half of the studied exoplanet atmospheres, albeit at varying extents. Accounting for stellar activity can significantly alter planetary atmospheric parameters like molecular abundances (up to 6 orders of magnitude) and temperature (up to 145%), contrasting with the results of analyses that neglect activity. Our results emphasize the importance of considering the effects of stellar contamination in exoplanet transit studies; this issue is particularly true for data sets obtained with facilities that do not cover the optical and/or UV spectral range where the activity is expected to be more impactful but also more easily detectable. Our results also provide a catalog of potentially active stars for further investigation and monitoring. |
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| institution | Kabale University |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-1ea258a612dd47728068553160b226942025-02-06T11:57:51ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127627010.3847/1538-4365/ad8c3cA Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar ContaminationArianna Saba0https://orcid.org/0000-0002-1437-4228Alexandra Thompson1https://orcid.org/0000-0003-4128-2270Kai Hou Yip2https://orcid.org/0000-0002-9616-1524Sushuang Ma3https://orcid.org/0000-0001-9010-0539Angelos Tsiaras4https://orcid.org/0000-0003-3840-1793Ahmed Faris Al-Refaie5https://orcid.org/0000-0003-2241-5330Giovanna Tinetti6https://orcid.org/0000-0001-6058-6654Department of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKDepartment of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKDepartment of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKDepartment of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKDepartment of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKDepartment of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKDepartment of Physics and Astronomy, University College London , Gower Street, WC1E 6BT London, UKWe present a population study of 20 exoplanets, ranging from Neptune-like to inflated hot-Jupiter planets, observed during transit with the Space Telescope Imaging Spectrograph (STIS) and Wide Field Camera 3 (WFC3) instruments on board the Hubble Space Telescope (HST). To obtain spectral information from the near-ultraviolet to the near-infrared, we reanalyzed 16 WFC3 and over 50 STIS archival data sets with our dedicated HST pipeline. We also include 24 WFC3 data sets previously reduced with the same software. Across our target sample, we observe significant divergence among multiple observations conducted with the same STIS grating at various epochs, while we do not detect variations in the WFC3 data sets. These results are suggestive of stellar contamination, which we have investigated further using known Bayesian tools and other tailored metrics, facilitating a more objective assessment of stellar activity intensity within each system. Our findings reveal that stellar activity contaminates up to half of the studied exoplanet atmospheres, albeit at varying extents. Accounting for stellar activity can significantly alter planetary atmospheric parameters like molecular abundances (up to 6 orders of magnitude) and temperature (up to 145%), contrasting with the results of analyses that neglect activity. Our results emphasize the importance of considering the effects of stellar contamination in exoplanet transit studies; this issue is particularly true for data sets obtained with facilities that do not cover the optical and/or UV spectral range where the activity is expected to be more impactful but also more easily detectable. Our results also provide a catalog of potentially active stars for further investigation and monitoring.https://doi.org/10.3847/1538-4365/ad8c3cExoplanet atmospheresBayesian statisticsSurveysStellar activityHubble Space TelescopeAstronomy data reduction |
| spellingShingle | Arianna Saba Alexandra Thompson Kai Hou Yip Sushuang Ma Angelos Tsiaras Ahmed Faris Al-Refaie Giovanna Tinetti A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination The Astrophysical Journal Supplement Series Exoplanet atmospheres Bayesian statistics Surveys Stellar activity Hubble Space Telescope Astronomy data reduction |
| title | A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination |
| title_full | A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination |
| title_fullStr | A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination |
| title_full_unstemmed | A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination |
| title_short | A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination |
| title_sort | population analysis of 20 exoplanets observed from optical to near infrared wavelengths with the hubble space telescope evidence for widespread stellar contamination |
| topic | Exoplanet atmospheres Bayesian statistics Surveys Stellar activity Hubble Space Telescope Astronomy data reduction |
| url | https://doi.org/10.3847/1538-4365/ad8c3c |
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