{"id":2028,"date":"2022-12-12T07:31:06","date_gmt":"2022-12-12T06:31:06","guid":{"rendered":"https:\/\/pepsi.aip.de\/?p=2028"},"modified":"2022-12-12T12:22:25","modified_gmt":"2022-12-12T11:22:25","slug":"untangling-the-sources-of-abundance-dispersion-in-low-metallicity-stars","status":"publish","type":"post","link":"https:\/\/pepsi.aip.de\/?p=2028","title":{"rendered":"Untangling the Sources of Abundance Dispersion in Low-Metallicity Stars"},"content":{"rendered":"\n<p>We measured abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample of 86 metal-poor subgiant stars in the solar neighborhood. Abundances are derived from high-resolution spectra taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument on the Large Binocular Telescope, modeled using iSpec and MOOG. By carefully quantifying the impact of photon-noise (&lt; 0.05 dex for all elements) we robustly measure the intrinsic scatter of abundance ratios. At fixed [Fe\/H] the RMS intrinsic scatter in [X\/Fe] ranges from 0.04 dex (Cr) to 0.16 dex (Na), with a median of 0.08 dex. Scatter in [X\/Mg] is similar, and accounting for [alpha\/Fe] only reduces the overall scatter moderately. We consider several possible origins of the intrinsic scatter with particular attention to fluctuations in the relative enrichment by core-collapse supernovae (CCSN) and Type Ia supernovae (SNIa) and stochastic sampling of the CCSN progenitor mass distribution. The stochastic sampling scenario provides a good quantitative explanation of our data if the effective number of CCSN contributing to the enrichment of a typical sample star is N approx 50. At the median metallicity of our sample, this interpretation implies that the CCSN ejecta are mixed over a gas mass 10<sup class=\"moz-txt-sup\">^5<\/sup> M<sub>Sun<\/sub> before forming stars. The scatter of elemental abundance ratios is a powerful diagnostic test for simulations of star formation, feedback, and gas mixing in the early phases of the Galaxy.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"329\" src=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/12\/F1_griffith-1024x329.png\" alt=\"\" class=\"wp-image-2027\" srcset=\"https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/12\/F1_griffith-1024x329.png 1024w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/12\/F1_griffith-300x96.png 300w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/12\/F1_griffith-768x246.png 768w, https:\/\/pepsi.aip.de\/wp-content\/uploads\/2022\/12\/F1_griffith.png 1265w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Spectral section from 5495\u22125535 A of three stars with [Fe\/H] near \u22122 (green), \u22121.5 (blue), and \u22121.0 (purple). Line features for Fe I, Ti I, Ca II, Sc II, and Mg I are labeled. Fluxes are normalized, with the [Fe\/H] \u2248 \u22121.5 spectrum offset by 0.5\nand the [Fe\/H] \u2248 \u22122 spectrum offset by 1.<\/figcaption><\/figure>\n\n\n\n<p>Read more:\u00a0 Griffith et al. 2022, ApJ, in press\u00a0 (<a href=\"https:\/\/arxiv.org\/pdf\/2210.01821.pdf\">arXiv:2210.01821<\/a>)<\/p>\n","protected":false},"excerpt":{"rendered":"<p>We measured abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample of 86 metal-poor subgiant stars in the solar neighborhood. Abundances are derived from high-resolution spectra taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument on the Large Binocular Telescope, modeled using iSpec and MOOG. &hellip; <a href=\"https:\/\/pepsi.aip.de\/?p=2028\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Untangling the Sources of Abundance Dispersion in Low-Metallicity Stars<\/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-2028","post","type-post","status-publish","format-standard","hentry","category-publications"],"_links":{"self":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/2028","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=2028"}],"version-history":[{"count":3,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/2028\/revisions"}],"predecessor-version":[{"id":2031,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=\/wp\/v2\/posts\/2028\/revisions\/2031"}],"wp:attachment":[{"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2028"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2028"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pepsi.aip.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2028"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}