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. 2021 September 3 [2]See Explanation. Clicking on the picture will download the highest resolution version available. NGC 7023: The Iris Nebula Image Credit & [3]Copyright: [4]Satwant Kumar Explanation: These cosmic clouds have blossomed 1,300 light-years away, in the fertile starfields of the [5]constellation Cepheus. Called the Iris Nebula, [6]NGC 7023 is not the only nebula to evoke the imagery [7]of flowers. Still, this [8]deep telescopic image shows off the Iris Nebula's range of colors and symmetries, embedded in surrounding fields of interstellar dust. Within the Iris itself, dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue, characteristic of dust grains reflecting starlight. [9]Central filaments of the reflection nebula glow with a faint reddish photoluminesence as some dust grains [10]effectively convert the star's invisible ultraviolet radiation to visible red light. Infrared [11]observations indicate that this nebula contains complex carbon molecules known as [12]PAHs. The dusty blue petals of the Iris Nebula span about six light-years. Tomorrow's picture: light-weekend __________________________________________________________________ [13]< | [14]Archive | [15]Submissions | [16]Index | [17]Search | [18]Calendar | [19]RSS | [20]Education | [21]About APOD | [22]Discuss | [23]> __________________________________________________________________ Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell ([27]UMCP) NASA Official: Phillip Newman [28]Specific rights apply. [29]NASA Web Privacy Policy and Important Notices A service of: [30]ASD at [31]NASA / [32]GSFC & [33]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2109/Irish_RC8_LHaRGB.png 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.astrobin.com/users/photonCatcher/ 5. http://hawastsoc.org/deepsky/cep/index.html 6. http://www.universetoday.com/17597/ngc-7023-iris-from-the-dust-by-kent-wood/ 7. https://apod.nasa.gov/apod/ap080214.html 8. https://www.astrobin.com/2bvs08/ 9. http://www.spacetelescope.org/news/heic0915/ 10. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1989ApJ...347L..25W&db_key=AST&high=3bc4bede8e21358 11. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2000A&A...354L..17M&db_key=AST&nosetcookie=1 12. https://www.spitzer.caltech.edu/news/feature07-03-spitzer-learns-about-carbons-cosmic-life 13. https://apod.nasa.gov/apod/ap210902.html 14. https://apod.nasa.gov/apod/archivepix.html 15. https://apod.nasa.gov/apod/lib/apsubmit2015.html 16. https://apod.nasa.gov/apod/lib/aptree.html 17. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 18. https://apod.nasa.gov/apod/calendar/allyears.html 19. https://apod.nasa.gov/apod.rss 20. https://apod.nasa.gov/apod/lib/edlinks.html 21. https://apod.nasa.gov/apod/lib/about_apod.html 22. http://asterisk.apod.com/discuss_apod.php?date=210903 23. https://apod.nasa.gov/apod/ap210904.html 24. http://www.phy.mtu.edu/faculty/Nemiroff.html 25. http://www.phy.mtu.edu/ 26. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 27. http://www.astro.umd.edu/ 28. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 29. https://www.nasa.gov/about/highlights/HP_Privacy.html 30. https://astrophysics.gsfc.nasa.gov/ 31. https://www.nasa.gov/ 32. https://www.nasa.gov/centers/goddard/ 33. http://www.mtu.edu/