Detail View: NASA Astronomy Picture of the Day Collection: NGC 7023: The Iris Nebula

Title: 
NGC 7023: The Iris Nebula
Explanation: 
Like delicate cosmic petals, these clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the constellation Cepheus [ http://www.astropix.com/HTML/E_SUM_N/ CEPHEUSO.HTM ]. Sometimes called the Iris Nebula and dutifully cataloged as NGC [ http://www.seds.org/billa/ngc.html ] 7023, this is not the only nebula in the sky to evoke the imagery of flowers [ http://antwrp.gsfc.nasa.gov/apod/ap010214.html ]. Still, the beautiful digital image [ http://www.heavensgloryobservatory.com/ ] shows off the Iris Nebula's range of colors and symmetries in impressive detail. Within the Iris, dusty nebular material surrounds a massive, hot, young star in its formative [ http://btc.montana.edu/ceres/html/ stars1.html#lessonplans ] years. Central filaments of cosmic dust glow with a reddish photoluminesence as some dust grains effectively convert [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query? bibcode=1989ApJ...347L..25W&db_key=AST&high=3bc4bede8e21358 ] the star's invisible ultraviolet [ http://imagers.gsfc.nasa.gov/ems/uv.html ] radiation to visible red light. Yet the dominant color of the nebula is blue, characteristic of dust [ http://www.physics.muni.cz/~ondra/mix/mix.html ] grains reflecting starlight. Dark, obscuring clouds of dust and cold molecular gas are also present and can lead the eye to see other convoluted [ http://antwrp.gsfc.nasa.gov/apod/ap010720.html ] and fantastic [ http://antwrp.gsfc.nasa.gov/apod/ap990829.html ] shapes. Infrared observations [ http://cdsads.u-strasbg.fr/cgi-bin/ nph-bib_query?2000A%26A...354L..17M&db_key=AST&nosetcookie=1 ] indicate that this nebula may contain complex carbon molecules known as PAHs [ http://www.chem.ucl.ac.uk/cosmicdust/pah.htm ]. As shown here, the Iris Nebula [ http://www.robgendlerastropics.com/ 7023.html ] is about 6 light-years across.
Credit and Copyright: 
Brian Lula [ mailto:brianl@polytecpi.com ]
keyword: 
dark nebula
facet_where: 
Goddard Space Flight Center (GSFC)
facet_what: 
Cepheus
original url: 
http://antwrp.gsfc.nasa.gov/apod/ap011214.html
UID: 
SPD-APOD-ap011214