{"id":645,"date":"2021-02-16T03:16:02","date_gmt":"2021-02-16T03:16:02","guid":{"rendered":"http:\/\/www.lunar.org\/wp\/?p=645"},"modified":"2021-02-16T03:16:02","modified_gmt":"2021-02-16T03:16:02","slug":"taking-the-dog-stars-for-a-springtime-walk-sirius-and-procyon","status":"publish","type":"post","link":"http:\/\/www.lunar.org\/wp\/?p=645","title":{"rendered":"Taking the Dog Stars for a Springtime Walk: Sirius and Procyon"},"content":{"rendered":"

David Prosper\"\"<\/a>
\nNASA JPL<\/p>\n

March skies feature many dazzling stars and constellations, glimmering high in the night, but two of the brightest stars are the focus of our attention this month: Sirius and Procyon, the dog stars!<\/p>\n

<\/p>\n

Sirius is the brightest star in the nighttime sky, in large part because it is one of the closest stars to our solar system at 8.6 light years away. Compared to our Sun, Sirius possesses twice the mass and is much younger. Sirius is estimated to be several hundred million<\/em> years old, just a fraction of the Sun\u2019s 4.6 billion<\/em> years. Near Sirius – around the width of a hand with fingers splayed out, held away at arm\u2019s length – you\u2019ll find Procyon, the 8th<\/sup> brightest star in the night sky. Procyon is another one of our Sun\u2019s closest neighbors, though a little farther away than Sirius, 11.5 light years away. While less massive than Sirius, it is much older and unusually luminous for a star of its type, leading astronomers to suspect that it may \u201csoon\u201d \u2013 at some point millions of years from now \u2013 swell into a giant star as it nears the end of its stellar life.<\/p>\n

Sirius and Procyon are nicknamed the \u201cDog Stars,\u201d an apt name as they are the brightest stars in their respective constellations \u2013 Canis Major and Canis Minor \u2013 whose names translate to \u201cBig Dog\u201d and \u201dLittle Dog.\u201d\u00a0 Not everyone sees them as canine companions. As two of the brightest stars in the sky, they feature prominently in the sky stories of cultures around the world. Sirius also captures the imaginations of people today: when rising or setting near the horizon, its brilliance mixes with our atmosphere\u2019s turbulence, causing the star\u2019s light to shimmer with wildly flickering color. This vivid, eerie sight was an indication to ancient peoples of changes in the seasons, and even triggers UFO reports in the modern era!<\/p>\n

Both of these bright stars have unseen companions: tiny, dense white dwarf stars, the remnants of supermassive companion stars. Interestingly, both of these dim companions were inferred from careful studies of their parent stars\u2019 movements in the 1800s, before they were ever directly observed! They are a challenging observation, even with a large telescope, since their parent stars are so very bright that their light overwhelms the much dimmer light of their tiny companions. The white dwarf stars, just like their parent stars, have differences: Sirius B is younger, brighter, and more energetic than Procyon B. Careful observations of these nearby systems over hundreds of years have helped advance the fields of: astrometry, the precise measurement of stars; stellar evolution; and astroseismology, the study of the internal structure of stars via their oscillations. Discover more about our stellar neighborhood at nasa.gov<\/a>!<\/p>\n

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Sirius and Procyon, the loyal hunting dogs of nearby Orion the Hunter! What other stories can you imagine for these stars?\u00a0 Learn about \u201cLegends in the Sky\u201d and create your own with this activity: https:\/\/bit.ly\/legendsinthesky<\/a> \u00a0 \u00a0 Image created with assistance from Stellarium.<\/em><\/p>\n

\"\"<\/a>Sirius A and B imaged by two different space telescopes, revealing dramatically different views! Hubble\u2019s image (left) <\/em>shows Sirius A shining brightly in visible light, with diminutive Sirius B a tiny dot. However, in Chandra\u2019s image (right)<\/em> tiny Sirius B is dramatically brighter in X-rays! The \u201cUniverse in a Different Light\u201d activity highlights more surprising views of some familiar objects: http:\/\/bit.ly\/different-light-nsn <\/a>NASA, ESA, H. Bond (STScI), and M. Barstow (University of Leicester) (left); NASA\/SAO\/CXC (right)<\/em><\/p>\n

This article is distributed by NASA Night Sky Network\u00a0 <\/strong>The Night Sky Network program supports astronomy clubs across the USA dedicated to astronomy outreach. Visit nightsky.jpl.nasa.gov<\/a> to find local clubs, events, and more!<\/p>\n","protected":false},"excerpt":{"rendered":"

David Prosper NASA JPL March skies feature many dazzling stars and constellations, glimmering high in the night, but two of the brightest stars are the focus of our attention this month: Sirius and Procyon, the dog stars!<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[14],"tags":[],"class_list":["post-645","post","type-post","status-publish","format-standard","hentry","category-nasa-space-place"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=\/wp\/v2\/posts\/645","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=645"}],"version-history":[{"count":1,"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=\/wp\/v2\/posts\/645\/revisions"}],"predecessor-version":[{"id":648,"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=\/wp\/v2\/posts\/645\/revisions\/648"}],"wp:attachment":[{"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=645"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=645"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.lunar.org\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=645"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}