          APOD: 2017 November 8 - NGC 2261: Hubble s Variable Nebula

                         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.

                                2017 November 8
                                      [2]
                      NGC 2261: Hubble's Variable Nebula
    Image Credit: Hubble [3] , NASA [4] , ESA [5] ; Data:  Mark Clampin [6]
        (NASA's GSFC [7] ); Processing & License [8] : Judy Schmidt [9]

Explanation: What causes Hubble's Variable Nebula to vary? The unusual nebula
featured here changes its appearance [10]  noticeably in just a few weeks.
Discovered over 200 years ago and subsequently cataloged [11]  as NGC 2261,
the remarkable nebula is named for Edwin Hubble [12] , who studied it [13]
early last century. Fitting, perhaps, the featured image [14]  was taken by
another namesake of Hubble: the Space Telescope [15] . Hubble's Variable
Nebula [16]  is a reflection nebula [17] made of gas and fine dust [18]
fanning out from the star R Monocerotis. The faint nebula is about one
light-year [19]  across and lies about 2500 light-years away towards the
constellation [20]  of the Unicorn [21] (Monocerotis [22] ). The leading
variability explanation [23]  for Hubble's Variable Nebula [24]  holds that
dense knots of opaque dust pass close to R Mon [25]  and cast moving shadows
[26]  onto the reflecting dust seen in the rest of the nebula [27] .

Open Science: Browse 1,500+ codes in the Astrophysics Source Code Library [28]

                      Tomorrow's picture: open space [29]

-------------------------------------------------------------------------------
< [30] | Archive [31] | Submissions [32] | Index [33] | Search [34] | Calendar
  [35] | RSS [36] | Education [37] | About APOD [38] | Discuss [39] | > [40]
-------------------------------------------------------------------------------

    Authors & editors: Robert Nemiroff [41] (MTU [42] ) & Jerry Bonnell [43]
                                  (UMCP [44] )
          NASA Official:  Phillip Newman Specific rights apply [45] .
              NASA Web Privacy Policy and Important Notices [46]
              A service of: ASD [47]  at NASA [48]  / GSFC [49]
                           & Michigan Tech. U. [50]
----------
Site notes:
  [1] archivepix.html
  [2] image/1711/HubblesVariableNebula_HubbleSchmidt_1507.jpg
  [3] https://www.nasa.gov/mission_pages/hubble/main/index.html
  [4] https://www.nasa.gov/
  [5] http://www.esa.int/
  [6] https://science.gsfc.nasa.gov/sed/bio/mark.clampin-1
  [7] https://www.nasa.gov/goddard
  [8] https://creativecommons.org/licenses/by/2.0/
  [9] http://geckzilla.com/
  [10]
http://www.umanitoba.ca/faculties/science/astronomy/cbrown/imaging/hvn/
hvnanimation.html
  [11] http://spider.seds.org/ngc/ngc.html
  [12] https://en.wikipedia.org/wiki/Edwin_Hubble
  [13] http://adsabs.harvard.edu/abs/1916ApJ....44..190H
  [14] https://www.flickr.com/photos/geckzilla/34436743884/
  [15] https://www.nasa.gov/mission_pages/hubble/story/index.html
  [16] https://en.wikipedia.org/wiki/NGC_2261
  [17] https://apod.nasa.gov/apod/reflection_nebulae.html
  [18] ap990509.html
  [19] http://chandra.harvard.edu/photo/cosmic_distance.html
  [20] http://www.astro.wisc.edu/~dolan/constellations/constellations.html
  [21] https://en.wikipedia.org/wiki/Unicorn
  [22] https://en.wikipedia.org/wiki/Monoceros
  [23] http://adsabs.harvard.edu/abs/1978ApJ...226..455A
  [24]
https://www.cloudynights.com/topic/
535672-hubbles-variable-nebula-animation-22-frames-in-24-weeks/
  [25] http://adsabs.harvard.edu/abs/1997ApJ...489..210C
  [26] ap130215.html
  [27] http://hubblesite.org/image/904/news_release/1999-35
  [28] http://ascl.net/code/all
  [29] ap171109.html
  [30] ap171107.html
  [31] archivepix.html
  [32] lib/apsubmit2015.html
  [33] lib/aptree.html
  [34] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [35] calendar/allyears.html
  [36] /apod.rss
  [37] lib/edlinks.html
  [38] lib/about_apod.html
  [39] http://asterisk.apod.com/discuss_apod.php?date=171108
  [40] ap171109.html
  [41] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [42] http://www.phy.mtu.edu/
  [43] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [44] http://www.astro.umd.edu/
  [45] lib/about_apod.html#srapply
  [46] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [47] https://astrophysics.gsfc.nasa.gov/
  [48] https://www.nasa.gov/
  [49] https://www.nasa.gov/centers/goddard/
  [50] http://www.mtu.edu/
