Subj : Daily APOD Report To : All From : Ben Ritchey Date : Wed Jul 11 2018 10:18:05 APOD: 2018 July 11 - Symbiotic R Aquarii Astronomy Picture of the Day Discover the cosmos! [1] Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 July 11 [2] Symbiotic R Aquarii Image Credit: Hubble [3] , NASA [4] , ESA [5] ; Processing & License [6] : Judy Schmidt [7] Explanation: You can see it change in brightness with just binoculars over the course of a year. Variable star R Aquarii [8] is actually an interacting binary star system, two stars that seem to have a close, symbiotic relationship [9] . About 710 light years away, this intriguing system consists of a cool red giant star [10] and hot, dense white dwarf star [11] in mutual orbit around their common center of mass. The binary system's visible light is dominated by the red giant, itself a Mira [12] -type long period variable star [13] . But material in the cool giant star's extended envelope is pulled by gravity onto the surface of the smaller, denser white dwarf, eventually triggering [14] a thermonuclear explosion [15] and blasting material into space. The featured image [16] from the Hubble Space Telescope [17] shows the still-expanding ring of debris which spans less than a light year [18] and originated from a blast that would have been seen in the early 1770s. The evolution of [19] less understood energetic events producing high energy emission in the R Aquarii [20] system has been monitored since 2000 using Chandra X-ray Observatory [21] data. Tomorrow's picture: open space [22] ------------------------------------------------------------------------------- < [23] | Archive [24] | Submissions [25] | Index [26] | Search [27] | Calendar [28] | RSS [29] | Education [30] | About APOD [31] | Discuss [32] | > [33] ------------------------------------------------------------------------------- Authors & editors: Robert Nemiroff [34] (MTU [35] ) & Jerry Bonnell [36] (UMCP [37] ) NASA Official: Phillip Newman Specific rights apply [38] . NASA Web Privacy Policy and Important Notices [39] A service of: ASD [40] at NASA [41] / GSFC [42] & Michigan Tech. U. [43] ---------- Site notes: [1] archivepix.html [2] image/1807/Raquarii_HubbleSchmidt_3116.jpg [3] https://www.nasa.gov/mission_pages/hubble/main/index.html [4] https://www.nasa.gov/ [5] http://www.esa.int/ [6] https://creativecommons.org/licenses/by/2.0/ [7] http://geckzilla.com/ [8] https://www.aavso.org/vsots_raqr [9] http://chandra.harvard.edu/photo/2017/raqr/ [10] https://en.wikipedia.org/wiki/Red_giant [11] https://imagine.gsfc.nasa.gov/science/objects/dwarfs2.html [12] ap060722.html [13] https://www.aavso.org/public [14] ap060726.html [15] https://www.youtube.com/watch?v=RZKiWGT4Za4 [16] https://www.flickr.com/photos/geckzilla/37736684446/in/dateposted/ [17] https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/ what-is-the-hubble-space-telecope-58.html [18] https://spaceplace.nasa.gov/light-year/en/ [19] http://chandra.harvard.edu/photo/2017/raqr/animations.html [20] https://en.wikipedia.org/wiki/R_Aquarii [21] http://chandra.harvard.edu/index.html [22] ap180712.html [23] ap180710.html [24] archivepix.html [25] lib/apsubmit2015.html [26] lib/aptree.html [27] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search [28] calendar/allyears.html [29] /apod.rss [30] lib/edlinks.html [31] lib/about_apod.html [32] http://asterisk.apod.com/discuss_apod.php?date=180711 [33] ap180712.html [34] http://www.phy.mtu.edu/faculty/Nemiroff.html [35] http://www.phy.mtu.edu/ [36] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html [37] http://www.astro.umd.edu/ [38] lib/about_apod.html#srapply [39] https://www.nasa.gov/about/highlights/HP_Privacy.html [40] https://astrophysics.gsfc.nasa.gov/ [41] https://www.nasa.gov/ [42] https://www.nasa.gov/centers/goddard/ [43] http://www.mtu.edu/ --- Mystic BBS v1.12 A39 (Windows/32) * Origin: FIDONet - The Positronium Repository (1:393/68) .