{"id":925,"date":"2019-10-10T02:06:43","date_gmt":"2019-10-10T02:06:43","guid":{"rendered":"https:\/\/araucaria.camk.edu.pl\/?p=925"},"modified":"2021-09-25T00:36:27","modified_gmt":"2021-09-25T00:36:27","slug":"candidates-for-non-pulsating-stars-in-the-cepheid-instability-strip","status":"publish","type":"post","link":"https:\/\/araucaria.camk.edu.pl\/index.php\/2019\/10\/10\/candidates-for-non-pulsating-stars-in-the-cepheid-instability-strip\/","title":{"rendered":"Candidates for non-pulsating stars in the Cepheid instability strip"},"content":{"rendered":"\n<p>Surprising discovery of non-pulsating stars residing inside the instability of LMC Cepheids is further examined with the help of&nbsp;Str\u00f6mgren photometry.&nbsp;<\/p>\n\n\n\n<hr class=\"wp-block-separator has-text-color has-background is-style-dots\" style=\"background-color:#275b12;color:#275b12\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Candidates for non-pulsating stars located in the Cepheid instability strip in the Large Magellanic Cloud based on Str\u00f6mgren photometry<\/h3>\n\n\n\n<p><em>W. Narloch, G. Pietrzy\u0144ski, Z. Ko\u0142aczkowski, R. Smolec, M. G\u00f3rski, K. Kubiak, A. Udalski, I. Soszy\u0144ski, D. Graczyk, W. Gieren, P. Karczmarek, B. Zgirski, P. Wielg\u00f3rski, K. Suchomska, B. Pilecki, M. Taormina, M. Ka\u0142uszy\u0144ski<\/em><\/p>\n\n\n\n<p><a href=\"https:\/\/ui.adsabs.harvard.edu\/abs\/2019MNRAS.489.3285N\/abstract\">2019, MNRAS,&nbsp;489, 3285<\/a><\/p>\n\n\n\n<p>Based on OGLE photometric maps combined with Str\u00f6mgren photometry and Gaia DR2 data for four fields in the&nbsp;LMC we found 19 candidates for non-pulsating stars located&nbsp;in empirical instability strip. An analysis of their light curves&nbsp;downloaded from OGLE surveys confirmed that they are&nbsp;stable at the level of a few of mmag.<\/p>\n\n\n\n<div class=\"wp-block-image wp-image-926\"><figure class=\"aligncenter size-large is-resized\"><img decoding=\"async\" src=\"https:\/\/araucaria.camk.edu.pl\/wp-content\/uploads\/2020\/02\/nonpulsatingstars.png\" alt=\"\" class=\"wp-image-1259\" width=\"500\" srcset=\"https:\/\/araucaria.camk.edu.pl\/wp-content\/uploads\/2020\/02\/nonpulsatingstars.png 970w, https:\/\/araucaria.camk.edu.pl\/wp-content\/uploads\/2020\/02\/nonpulsatingstars-300x206.png 300w, https:\/\/araucaria.camk.edu.pl\/wp-content\/uploads\/2020\/02\/nonpulsatingstars-768x527.png 768w\" sizes=\"(max-width: 970px) 100vw, 970px\" \/><figcaption>Dereddened Str\u00f6mgren color-magnitude diagram for stars brighter 19 mag. Green dots mark candidates for non-pulsating stars (CAN). Blue and red lines mark the approximate position of the empirical IS determined on the basis of the OGLE cefeid and transformed into Str\u00f6mgren filters.<\/figcaption><\/figure><\/div>\n\n\n\n<p>Our results show that&nbsp;between about 21% to 30% of LMC giants located in the&nbsp;instability strip might not pulsate. More observations will be required&nbsp;for further investigation of the candidates, in order to find&nbsp;any signs of variability indicating kinds of behaviour other&nbsp;than classical pulsations, e.g., nonradial pulsation or binarity (where both components of the system lie in fact outside&nbsp;the IS).<\/p>\n\n\n\n<p>The relation (u\u2212b) \u2212log P plotted for classical Cepheids&nbsp;identified in the fields gave us two potential candidates for&nbsp;binary Cepheids with hot companions and two other are&nbsp;questionable. These systems might be interesting for further&nbsp;follow up spectroscopic observations to confirm these&nbsp; suspicions.<\/p>\n\n\n\n<div class=\"wp-block-image wp-image-927\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/araucaria.camk.edu.pl\/wp-content\/uploads\/2019\/10\/fig2.png\" alt=\"\" class=\"wp-image-927\" width=\"500\" height=\"292\"\/><figcaption>Color-period relation for classical Cepheids identified in the four fields in the LMC.<\/figcaption><\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Surprising discovery of non-pulsating stars residing inside the instability of LMC Cepheids is further examined with the help of\u00a0Str\u00f6mgren photometry.<\/p>\n","protected":false},"author":1,"featured_media":926,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[11,19],"class_list":["post-925","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science-highlights","tag-cepheid","tag-lmc"],"_links":{"self":[{"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/posts\/925","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/comments?post=925"}],"version-history":[{"count":6,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/posts\/925\/revisions"}],"predecessor-version":[{"id":1870,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/posts\/925\/revisions\/1870"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/media\/926"}],"wp:attachment":[{"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/media?parent=925"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/categories?post=925"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/araucaria.camk.edu.pl\/index.php\/wp-json\/wp\/v2\/tags?post=925"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}