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 July 6 [2]See Explanation. Clicking on the picture will download the highest resolution version available. NGC 7789: Caroline's Rose Image Credit & [3]Copyright: [4]Massimo Di Fusco Explanation: Found among the rich starfields of the Milky Way, [5]star cluster NGC 7789 lies about 8,000 light-years away toward the constellation Cassiopeia. A late 18th century deep sky discovery of astronomer [6]Caroline Lucretia Herschel, the cluster is also known as Caroline's Rose. Its [7]visual appearance in small telescopes, created by the cluster's complex of stars and voids, is suggestive of nested rose petals. Now estimated to be 1.6 billion years young, the galactic or open [8]cluster of stars also shows its age. All the stars in the cluster were likely born at the same time, but the brighter and more massive ones have more rapidly exhausted the hydrogen fuel in their cores. These have evolved from [9]main sequence stars like the Sun into the many red giant stars shown with a yellowish cast in this color composite. Using measured [10]color and brightness, astronomers can model the mass and hence the age of the cluster stars just starting to "turn off" the main sequence and become [11]red giants. Over 50 light-years across, [12]Caroline's Rose spans about half a degree (the angular size of the Moon) near the center of [13]the sharp telescopic image. Tomorrow's picture: cloudy skies __________________________________________________________________ [14]< | [15]Archive | [16]Submissions | [17]Index | [18]Search | [19]Calendar | [20]RSS | [21]Education | [22]About APOD | [23]Discuss | [24]> __________________________________________________________________ Authors & editors: [25]Robert Nemiroff ([26]MTU) & [27]Jerry Bonnell ([28]UMCP) NASA Official: Amber Straughn [29]Specific rights apply. [30]NASA Web Privacy, [31]Accessibility Notices A service of: [32]ASD at [33]NASA / [34]GSFC, [35]NASA Science Activation & [36]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2407/NGC7789_difusco2048.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.astrobin.com/users/massimo.difusco/ 5. http://messier.seds.org/xtra/ngc/n7789.html 6. https://skyandtelescope.org/observing/in-caroline-herschels-footsteps/ 7. https://skyandtelescope.org/astronomy-news/explore-caroline-herschels-celestial-showpieces/ 8. https://science.nasa.gov/mission/hubble/science/universe-uncovered/hubble-star-clusters/ 9. http://en.wikipedia.org/wiki/Main_sequence 10. https://apod.nasa.gov/apod/ap010223.html 11. https://apod.nasa.gov/apod/ap110408.html 12. http://adsbit.harvard.edu//full/1848MNRAS...8...64./0000064.000.html 13. https://www.astrobin.com/4qk8jq/0/ 14. https://apod.nasa.gov/apod/ap240705.html 15. https://apod.nasa.gov/apod/archivepix.html 16. https://apod.nasa.gov/apod/lib/apsubmit2015.html 17. https://apod.nasa.gov/apod/lib/aptree.html 18. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 19. https://apod.nasa.gov/apod/calendar/allyears.html 20. https://apod.nasa.gov/apod.rss 21. https://apod.nasa.gov/apod/lib/edlinks.html 22. https://apod.nasa.gov/apod/lib/about_apod.html 23. http://asterisk.apod.com/discuss_apod.php?date=240706 24. https://apod.nasa.gov/apod/ap240707.html 25. http://www.phy.mtu.edu/faculty/Nemiroff.html 26. http://www.phy.mtu.edu/ 27. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 28. http://www.astro.umd.edu/ 29. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 30. https://www.nasa.gov/about/highlights/HP_Privacy.html 31. https://www.nasa.gov/general/accessibility/ 32. https://astrophysics.gsfc.nasa.gov/ 33. https://www.nasa.gov/ 34. https://www.nasa.gov/centers/goddard/ 35. https://science.nasa.gov/learners 36. http://www.mtu.edu/