﻿ 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. 2024 February 12 [2]The image shows a dark field filled with stars and a diffuse red nebula running across horizontally. In the field are two circular objects that are bright, light colored. The lower object is larger and encircled in a blue glow. Please see the explanation for more detailed information. HFG1 & Abell 6: Planetary Nebulae Image Credit & Copyright: [3]Julien Cadena & [4]Mickael Coulon; Text: [5]Natalia Lewandowska ([6]SUNY Oswego) Explanation: [7]Planetary nebulae like [8]Heckathorn-Fesen-Gull 1 (HFG1) and [9]Abell 6 in the constellation [10]Cassiopeia are remnants from the last phase of a [11]medium sized star like our [12]Sun. In spite of their shapes, planetary nebulae have [13]nothing in common with actual planets. Located in the bottom left part of the [14]featured photo, HFG1 was created by the [15]binary star system V664 Cas, which consists of a [16]white dwarf star and a [17]red giant star. Both stars orbit their [18]center of mass over about [19]half an Earth day. Traveling with the entire nebula at a speed about 300 times faster than the fastest train on Earth, V664 Cas generates a [20]bluish arc shaped [21]shock wave. The wave interacts most strongly with the surrounding [22]interstellar medium in the areas where the arc is brightest. After roughly [23]10,000 years, planetary nebulae become invisible due to a lack of [24]ultraviolet light being emitted by the [25]stars that create them. Displaying [26]beautiful shapes and structures, planetary nebulae are [27]highly desired objects for astrophotographers. Tomorrow's picture: a wolf moon __________________________________________________________________ [28]< | [29]Archive | [30]Submissions | [31]Index | [32]Search | [33]Calendar | [34]RSS | [35]Education | [36]About APOD | [37]Discuss | [38]> __________________________________________________________________ Authors & editors: [39]Robert Nemiroff ([40]MTU) & [41]Jerry Bonnell ([42]UMCP) NASA Official: Amber Straughn; [43]Specific rights apply. [44]NASA Web Privacy Policy and Important Notices A service of: [45]ASD at [46]NASA / [47]GSFC, [48]NASA Science Activation & [49]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2402/Hfg1Abell6_CadenaCoulon_6140.jpg 3. https://www.astrobin.com/users/JulienCadena/ 4. https://www.instagram.com/mickael_coulon_astrophoto/ 5. https://www.oswego.edu/physics/natalia-lewandowska 6. https://www.oswego.edu/physics/ 7. https://en.wikipedia.org/wiki/Planetary_nebula 8. https://www.sternwarte-baerenstein.de/hfg1-abell6-en.html 9. https://in-the-sky.org/data/object.php?id=Abell_6 10. https://en.wikipedia.org/wiki/Cassiopeia_(constellation) 11. https://imagine.gsfc.nasa.gov/educators/lifecycles/SC_main_p1.html 12. https://science.nasa.gov/sun 13. https://images.squarespace-cdn.com/content/v1/5b631cba5b409b413bb3a633/1533669968141-15YL8HF098WAOR8RYKFD/A-dog-looking-confused-and-surprised.jpg 14. https://www.facebook.com/ZwoDesignAstronomyCameras/posts/802324015256448 15. https://science.nasa.gov/universe/stars/multiple-star-systems/ 16. https://apod.nasa.gov/apod/ap231224.html 17. https://apod.nasa.gov/apod/ap110408.html 18. https://spaceplace.nasa.gov/barycenter/en/ 19. https://www.astro.oma.be/en/gaia-observes-a-cosmic-clock-inside-a-large-planetary-nebula/ 20. https://www.astronomersdoitinthedark.com/index.php?c=145&p=571 21. https://apod.nasa.gov/apod/ap240104.html 22. https://en.wikipedia.org/wiki/Interstellar_medium 23. http://koreascience.or.kr/article/JAKO200502637762045.page 24. https://science.nasa.gov/ems/10_ultravioletwaves 25. https://en.wikipedia.org/wiki/Star 26. https://apod.nasa.gov/apod/ap240107.html 27. https://skynews.ca/hfg1-abell-6-by-dan-kusz/ 28. https://apod.nasa.gov/apod/ap240211.html 29. https://apod.nasa.gov/apod/archivepix.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.com/feed.rss 35. https://apod.nasa.gov/apod/lib/edlinks.html 36. https://apod.nasa.gov/apod/lib/about_apod.html 37. https://asterisk.apod.com/discuss_apod.php?date=240212 38. https://apod.nasa.gov/apod/ap240213.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. https://science.nasa.gov/learners 49. http://www.mtu.edu/