{"id":170537,"date":"2024-11-19T21:05:14","date_gmt":"2024-11-19T21:05:14","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=170537"},"modified":"2024-11-19T21:05:16","modified_gmt":"2024-11-19T21:05:16","slug":"how-is-a-cepheid-variable-star-identified","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2024\/11\/19\/how-is-a-cepheid-variable-star-identified\/","title":{"rendered":"How is a cepheid Variable star identified"},"content":{"rendered":"\n

How is a cepheid Variable star identified?
Pulsates radically with a clear change in Luminosity<\/p>\n\n\n\n

It\u2019s luminosity dims as it rotates<\/p>\n\n\n\n

It\u2019s being torn apart by tidal forces<\/p>\n\n\n\n

It\u2019s brightness appears to change during transit<\/p>\n\n\n\n

The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n

The correct answer is:<\/p>\n\n\n\n

Pulsates radically with a clear change in luminosity.<\/strong><\/p>\n\n\n\n

Explanation:<\/h3>\n\n\n\n

A Cepheid variable star is a type of pulsating star whose luminosity (or brightness) changes in a regular and predictable pattern due to periodic expansion and contraction of the star’s outer layers. These stars are crucial to astronomers because their pulsation period is directly related to their intrinsic luminosity, making them key “standard candles” for measuring astronomical distances.<\/p>\n\n\n\n

The defining feature of a Cepheid variable star is its pulsation<\/strong>\u2014the star’s outer layers expand and contract over a regular period. This pulsation leads to variations in brightness, as the star\u2019s surface temperature and size change during the cycle. The change in luminosity is what allows astronomers to identify a Cepheid variable star. These stars are typically brighter during their expanded phase and dimmer when contracted.<\/p>\n\n\n\n

The pulsation of Cepheid variables is driven by a process known as the “instability strip”<\/strong> in the Hertzsprung-Russell diagram, where stars become unstable and undergo regular oscillations. The period of pulsation is linked to the star’s luminosity via the Leavitt Law<\/strong> (or the Period-Luminosity Relation<\/strong>), which states that the longer the pulsation period, the greater the luminosity of the star. This relationship makes Cepheid variables invaluable tools for measuring distances to galaxies.<\/p>\n\n\n\n

In contrast, the other options listed are not characteristic of Cepheid variables:<\/p>\n\n\n\n

    \n
  • Luminosity dims as it rotates<\/strong>: This is more likely to apply to stars that experience starspots or other rotational variations, not Cepheid variables.<\/li>\n\n\n\n
  • Being torn apart by tidal forces<\/strong>: This is typical of stars in binary systems or those near black holes, but not Cepheid variables.<\/li>\n\n\n\n
  • Brightness appears to change during transit<\/strong>: This describes a transit event where a planet passes in front of a star, not the intrinsic pulsation of a Cepheid star.<\/li>\n<\/ul>\n\n\n\n

    Therefore, the key identifying characteristic of a Cepheid variable star is the radical pulsation with clear changes in luminosity.<\/p>\n","protected":false},"excerpt":{"rendered":"

    How is a cepheid Variable star identified?Pulsates radically with a clear change in Luminosity It\u2019s luminosity dims as it rotates It\u2019s being torn apart by tidal forces It\u2019s brightness appears to change during transit The Correct Answer and Explanation is : The correct answer is: Pulsates radically with a clear change in luminosity. Explanation: A […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-170537","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/170537","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=170537"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/170537\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=170537"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=170537"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=170537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}