{"id":2280,"date":"2025-11-21T12:38:42","date_gmt":"2025-11-21T11:38:42","guid":{"rendered":"https:\/\/pepsi.aip.de\/?p=2280"},"modified":"2025-11-21T12:38:42","modified_gmt":"2025-11-21T11:38:42","slug":"pepsi-investigation-retrieval-and-atlas-of-numerous-giant-atmospheres-piranga-iv-high-resolution-phased-resolved-spectroscopy-of-the-ultra-hot-jupiter-kelt-20-b","status":"publish","type":"post","link":"https:\/\/pepsi.aip.de\/?p=2280","title":{"rendered":"PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). IV.High-Resolution Phased-Resolved Spectroscopy of The Ultra Hot Jupiter KELT-20 b"},"content":{"rendered":"\n<p>We present five datasets of high-resolution optical emission spectra of the ultra-hot Jupiter KELT-20 b with the PEPSI spectrograph. Using a Bayesian retrieval framework, we constrain its dayside pressure-temperature profile and abundances of Fe, Ni, and Ca, providing the first measurements for Ni and Ca for KELT-20 b in emission. We retrieve the pre- and post-eclipse datasets separately (corresponding to the evening and morning sides, respectively), and compare the constraints on their thermal structures and chemical abundances. We constrain lower abundances in the pre-eclipse datasets compared to the post-eclipse datasets. We interpret these results with an equilibrium chemistry model which suggests \u223c 10 \u2212 30\u00d7 supersolar refractory abundances. Due to the well-known degeneracy between absolute abundances and continuum opacities, the abundance ratios are more precise probes of the planetary abundances. Therefore we measure the abundance ratios [Ni\/Fe] and [Ca\/Fe] across these datasets and find they agree within 1\u03c3. We constrain [Ni\/Fe] to be consistent with solar within 2\u03c3, and [Ca\/Fe] to be 0.001-0.01\u00d7 solar, not accounting for ionization.<\/p>\n\n\n\n<figure id=\"attachment_2277\" aria-describedby=\"caption-attachment-2277\" style=\"width: 1343px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2025\/11\/Piranga-4.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-2277\" src=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2025\/11\/Piranga-4.png\" alt=\"\" width=\"1343\" height=\"1139\" srcset=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2025\/11\/Piranga-4.png 1343w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2025\/11\/Piranga-4-300x254.png 300w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2025\/11\/Piranga-4-1024x868.png 1024w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2025\/11\/Piranga-4-768x651.png 768w\" sizes=\"auto, (max-width: 1343px) 100vw, 1343px\" \/><\/a><figcaption id=\"caption-attachment-2277\" class=\"wp-caption-text\">Top-down view of KELT-20 b\u2019s orbit as it passes behind its host star, moving counterclockwise from pre-eclipse to post-eclipse. The orange side depicts the hot day side, while the blue side corresponds to the cooler night side of the tidally-locked planet. The translucent gray side depicts the side of the planet that is outside of the view of the observer, who is positioned off the bottom of the page.<\/figcaption><\/figure>\n\n\n\n<p>Read more: Bonidie et al. 2025, AJ, in press.\u00a0 eprint <a href=\"http:\/\/arXiv:2511.09720\">arXiv:2511.09720<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>We present five datasets of high-resolution optical emission spectra of the ultra-hot Jupiter KELT-20 b with the PEPSI spectrograph. Using a Bayesian retrieval framework, we constrain its dayside pressure-temperature profile and abundances of Fe, Ni, and Ca, providing the first measurements for Ni and Ca for KELT-20 b in emission. We retrieve the pre- and &hellip; <a href=\"https:\/\/pepsi.aip.de\/?p=2280\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). IV.High-Resolution Phased-Resolved Spectroscopy of The Ultra Hot Jupiter KELT-20 b<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-2280","post","type-post","status-publish","format-standard","hentry","category-publications"],"_links":{"self":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/2280","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2280"}],"version-history":[{"count":1,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/2280\/revisions"}],"predecessor-version":[{"id":2281,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/2280\/revisions\/2281"}],"wp:attachment":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2280"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2280"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2280"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}