Astronomy Picture of the Day

                         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 October 29
                                      [2]
                Shells of Stars in Elliptical Galaxy PGC 42871
  Image Credit: Hubble Legacy Archive [3] , NASA [4] , ESA [5] ; Processing &
                        Copyright: Domingo Pestana [6]

Explanation: How do galaxies grow? To help find out, the Hubble Space
Telescope [7]  was deployed to image the unusual elliptical galaxy [8] PGC
42871. How this galaxy came to be surrounded by numerous shells of stars [9]
may give clues about how it evolved. Embedded in the diffuse shells [10]  are
massive globular clusters of stars [11]  -- stars which analyses show were
born during three different epochs. This and other data indicate [12]  that
PGC 42871 [13]  has been in at least two galactic collisions [14] , at least
one of which might have been with a former spiral galaxy [15] . The remaining
spiral galaxy on the far left is at the same distance as PGC 42871 [16]  and
may have been involved in some of the collisions. PGC 42871 spans about 20
thousand light years [17]  and lies about 270 million light years away toward
[18] the constellation of Centaurus [19] .

Open Science: Browse 1,800+ codes in the Astrophysics Source Code Library [20]

                    Tomorrow's picture: orionids from orion

-------------------------------------------------------------------------------
< [21] | Archive [22] | Submissions [23] | Index [24] | Search [25] | Calendar
  [26] | RSS [27] | Education [28] | About APOD [29] | Discuss [30] | > [31]
-------------------------------------------------------------------------------

    Authors & editors: Robert Nemiroff [32] (MTU [33] ) & Jerry Bonnell [34]
                                  (UMCP [35] )
          NASA Official:  Phillip Newman Specific rights apply [36] .
              NASA Web Privacy Policy and Important Notices [37]
              A service of: ASD [38]  at NASA [39]  / GSFC [40]
                           & Michigan Tech. U. [41]
----------
Site notes:
  [1] archivepix.html
  [2] image/1810/PGC42871_HubblePestana_5051.jpg
  [3] https://hla.stsci.edu/
  [4] https://www.nasa.gov/
  [5] https://www.esa.int/
  [6] https://www.flickr.com/photos/122467237@N08/
  [7] https://www.spacetelescope.org/announcements/...
  [8] https://en.wikipedia.org/wiki/Elliptical_gala...
  [9] ap180206.html
  [10] ap140105.html
  [11] ap160427.html
  [12] http://adsabs.harvard.edu/abs/2009AJ....137.....
  [13] https://www.spacetelescope.org/news/heic1516/
  [14] ap130514.html
  [15] https://www.nasa.gov/multimedia/imagegallery/...
  [16] https://www.spacetelescope.org/images/heic151...
  [17] https://starchild.gsfc.nasa.gov/docs/StarChil...
  [18] https://www.youtube.com/watch?v=0gYTXaLWqyI
  [19] https://en.wikipedia.org/wiki/Centaurus
  [20] http://ascl.net/code/all
  [21] ap181028.html
  [22] archivepix.html
  [23] lib/apsubmit2015.html
  [24] lib/aptree.html
  [25] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [26] calendar/allyears.html
  [27] /apod.rss
  [28] lib/edlinks.html
  [29] lib/about_apod.html
  [30] http://asterisk.apod.com/discuss_apod.php?dat...
  [31] ap181030.html
  [32] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [33] http://www.phy.mtu.edu/
  [34] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [35] http://www.astro.umd.edu/
  [36] lib/about_apod.html#srapply
  [37] https://www.nasa.gov/about/highlights/HP_Priv...
  [38] https://astrophysics.gsfc.nasa.gov/
  [39] https://www.nasa.gov/
  [40] https://www.nasa.gov/centers/goddard/
  [41] http://www.mtu.edu/

--- Mystic BBS v1.12 A39 (Windows/32)
 * Origin: FIDONet - The Positronium Repository (1:393/68)