Astronomy Picture of the Day

   [1]Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                              2022 February 24
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                            Beautiful Albireo AB
                 Image Credit & [3]Copyright: [4]Robert Eder

   Explanation: [5]Beta Cygni is a single bright star to the naked eye.
   About 420 light-years away it marks the foot of the Northern Cross,
   famous asterism in the constellation Cygnus. But a view through the
   eyepiece of a small telescope will transform it into a beautiful double
   star, a [6]treasure of the night sky in blue and gold. Beta Cygni is
   [7]also known as Albireo, designated Albireo AB to indicate its two
   bright component stars. Their visually striking color difference is
   illustrated [8]in this telescopic snapshot, along with their associated
   [9]visible spectrum of starlight shown in insets to the right. Albireo
   A, top inset, shows the spectrum of a K-type giant star, cooler than
   the Sun and emitting most of its energy at yellow and red wavelengths.
   Below, Albireo B has the spectrum of a main sequence star much hotter
   than the Sun, emitting more energy in blue and violet. [10]Albireo A is
   known to be a binary star, two stars together orbiting a common center
   of mass, though the two stars are too close together to be seen
   separately with a small telescope. Well-separated Albireo A and B most
   likely represent an optical double star and not a physical binary
   system [11]because the two components have clearly different measured
   motions through space.

                     Tomorrow's picture: mars with moxie
     __________________________________________________________________

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    Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell
                                 ([26]UMCP)
          NASA Official: Phillip Newman [27]Specific rights apply.
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                A service of: [29]ASD at [30]NASA / [31]GSFC
                           & [32]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2202/albireoSpectrum.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.astrobin.com/users/Robsi/
   5. https://en.wikipedia.org/wiki/Albireo
   6. https://earthsky.org/brightest-stars/albireo-finest-double-star/
   7. http://stars.astro.illinois.edu/sow/albireo.html
   8. https://www.astrobin.com/xssrcf/
   9. https://science.nasa.gov/ems/09_visiblelight
  10. https://en.wikipedia.org/wiki/Albireo#Albireo_A
  11. https://arxiv.org/abs/1811.01665
  12. https://apod.nasa.gov/apod/ap220223.html
  13. https://apod.nasa.gov/apod/archivepix.html
  14. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  15. https://apod.nasa.gov/apod/lib/aptree.html
  16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  17. https://apod.nasa.gov/apod/calendar/allyears.html
  18. https://apod.nasa.gov/apod.rss
  19. https://apod.nasa.gov/apod/lib/edlinks.html
  20. https://apod.nasa.gov/apod/lib/about_apod.html
  21. http://asterisk.apod.com/discuss_apod.php?date=220224
  22. https://apod.nasa.gov/apod/ap220225.html
  23. http://www.phy.mtu.edu/faculty/Nemiroff.html
  24. http://www.phy.mtu.edu/
  25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  26. http://www.astro.umd.edu/
  27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  28. https://www.nasa.gov/about/highlights/HP_Privacy.html
  29. https://astrophysics.gsfc.nasa.gov/
  30. https://www.nasa.gov/
  31. https://www.nasa.gov/centers/goddard/
  32. http://www.mtu.edu/