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.

                              2019 December 18
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                A Hotspot Map of Neutron Star J0030's Surface
            Image Credit: [3]NASA, [4]NICER, [5]GSFC's [6]CI Lab

   Explanation: What do neutron stars look like? Previously these
   [7]city-sized stars were too small and too far away to resolve.
   Recently, however, the [8]first maps of the locations and sizes of
   [9]hotspots on a neutron star's surface have been made by carefully
   modeling how the rapid spin makes the star's [10]X-ray brightness rise
   and fall. Based on a leading model, an [11]illustrative map of
   [12]pulsar [13]J0030+0451's hotspots is pictured, with the rest of the
   star's surface filled in with a false patchy blue. [14]J0030 spins once
   every 0.0049 seconds and is located about 1000 [15]light years away.
   [16]The map was computed from data taken by NASA's Neutron star
   Interior Composition ExploreR ([17]NICER) X-ray telescope attached to
   the [18]International Space Station. The [19]computed locations of
   [20]these hotspots is surprising and not well understood. Because the
   gravitational [21]lensing effect of neutron stars is so strong, J0300
   [22]displays more than half of its surface toward the Earth.
   [23]Studying the [24]appearance of pulsars like J0030 allows accurate
   estimates of the [25]neutron star's mass, radius, and the [26]internal
   physics that keeps the star from imploding into a [27]black hole.

                       Tomorrow's picture: open space
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    Authors & editors: [39]Robert Nemiroff ([40]MTU) & [41]Jerry Bonnell
                                 ([42]UMCP)
          NASA Official: Phillip Newman [43]Specific rights apply.
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                A service of: [45]ASD at [46]NASA / [47]GSFC
                           & [48]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix2015.html
   2. https://apod.nasa.gov/apod/image/1912/J0030_NICER_1024.jpg
   3. https://www.nasa.gov/
   4. https://www.nasa.gov/content/about-nicer
   5. https://www.nasa.gov/goddard
   6. https://svs.gsfc.nasa.gov/cilab/index.html
   7. https://media.ligo.northwestern.edu/gallery/neutron-star-over-chicago
   8. https://www.nasa.gov/feature/goddard/2019/nasa-s-nicer-delivers-best-ever-pulsar-measurements-1st-surface-map
   9. https://phys.org/news/2018-04-magnetic-hot-neutron-stars-survive.html
  10. https://science.nasa.gov/ems/11_xrays
  11. https://svs.gsfc.nasa.gov/13240
  12. https://en.wikipedia.org/wiki/Pulsar
  13. https://arxiv.org/abs/0904.4377
  14. https://www.forbes.com/sites/startswithabang/2019/12/16/nasas-nicer-mission-reveals-an-unexpected-neutron-star-surprise/
  15. https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html
  16. https://cms.iopscience.org/c5dfe599-1b5b-11ea-8ae4-b3312b4ab81c/J0030_Model_Side-by-Side_.gif
  17. https://www.nasa.gov/content/about-nicer
  18. https://apod.nasa.gov/apod/ap151109.html
  19. https://ui.adsabs.harvard.edu/abs/2019ApJ...887L..24M/abstract
  20. https://ui.adsabs.harvard.edu/abs/2019ApJ...887L..21R/abstract
  21. https://ui.adsabs.harvard.edu/abs/1986ApJ...300..203F/abstract
  22. https://apod.nasa.gov/htmltest/rjn_bht.html
  23. https://images.all-free-download.com/images/graphiclarge/cat_staring_at_fish_in_jar_596232.jpg
  24. https://ui.adsabs.harvard.edu/abs/2019ApJ...887L..26B/abstract
  25. https://apod.nasa.gov/apod/ap180930.html
  26. https://iopscience.iop.org/journal/2041-8205/page/Focus_on_NICER_Constraints_on_the_Dense_Matter_Equation_of_State
  27. http://cosmology.berkeley.edu/Education/BHfaq.html
  28. https://apod.nasa.gov/apod/ap191217.html
  29. https://apod.nasa.gov/apod/archivepix2015.html
  30. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  31. https://apod.nasa.gov/apod/lib/aptree.html
  32. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  33. https://apod.nasa.gov/apod/calendar/allyears.html
  34. https://apod.nasa.gov/apod.rss
  35. https://apod.nasa.gov/apod/lib/edlinks.html
  36. https://apod.nasa.gov/apod/lib/about_apod.html
  37. http://asterisk.apod.com/discuss_apod.php?date=191218
  38. https://apod.nasa.gov/apod/ap191219.html
  39. http://www.phy.mtu.edu/faculty/Nemiroff.html
  40. http://www.phy.mtu.edu/
  41. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  42. http://www.astro.umd.edu/
  43. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  44. https://www.nasa.gov/about/highlights/HP_Privacy.html
  45. https://astrophysics.gsfc.nasa.gov/
  46. https://www.nasa.gov/
  47. https://www.nasa.gov/centers/goddard/
  48. http://www.mtu.edu/