¿ 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 June 7 [2]A deep image toward the constellation of Cassiopeia showing transient Nova Cas as it appeared in 2021 March. Please see the explanation for more detailed information. A Bright Nova in Cassiopeia Image Credit & Copyright: [3]Chuck Ayoub Explanation: What's that new spot of light in Cassiopeia? A nova. Although [4]novas occur frequently throughout the universe, this nova, known as [5]Nova Cas 2021 or V1405 Cas, became so unusually bright in the skies of Earth last month that it was visible to the [6]unaided eye. Nova Cas 2021 first brightened in mid-March but then, unexpectedly, became even brighter in mid-May and remained [7]quite bright for about a week. The nova then faded back to early-May levels, but now is slightly brightening again and [8]remains visible through binoculars. Identified by the arrow, the nova occurred toward the [9]constellation of Cassiopeia, not far from the [10]Bubble Nebula. A nova is typically caused by a [11]thermonuclear explosion on the surface of a [12]white dwarf star that is [13]accreting matter from a [14]binary-star companion -- although details of this outburst are currently unknown. Novas don't destroy the underlying star, and are [15]sometimes seen to recur. The [16]featured image was created from 14 hours of imaging from [17]Detroit, [18]Michigan, [19]USA. Both professional and amateur astronomers will likely continue to monitor [20]Nova Cas 2021 and [21]hypothesize about details of its cause. Tomorrow's picture: Jupiter happy __________________________________________________________________ [22]< | [23]Archive | [24]Submissions | [25]Index | [26]Search | [27]Calendar | [28]RSS | [29]Education | [30]About APOD | [31]Discuss | [32]> __________________________________________________________________ Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell ([36]UMCP) NASA Official: Phillip Newman [37]Specific rights apply. [38]NASA Web Privacy Policy and Important Notices A service of: [39]ASD at [40]NASA / [41]GSFC & [42]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2106/NovaCasAndFriends_Ayoub_2230.jpg 3. https://www.instagram.com/chucksastrophotography/ 4. https://imagine.gsfc.nasa.gov/science/objects/cataclysmic_variables.html 5. https://skyandtelescope.org/astronomy-news/observing-news/bright-nova-erupts-in-cassiopeia/ 6. https://www.visiondirect.co.uk/the-human-eye 7. https://app.aavso.org/webobs/results/?star=000-BNX-642#_results=200 8. https://www.aavso.org/LCGv2/ 9. https://en.wikipedia.org/wiki/Cassiopeia_(constellation) 10. https://apod.nasa.gov/apod/ap170531.html 11. https://youtu.be/aHY2a145p0Y 12. https://apod.nasa.gov/apod/ap150517.html 13. https://apod.nasa.gov/apod/ap200831.html 14. https://astronomy.swin.edu.au/cosmos/b/binary+star 15. https://apod.nasa.gov/apod/ap150111.html 16. https://www.instagram.com/p/CPnkyX8p8sX/ 17. https://youtu.be/k-dc-VQQwIA 18. https://en.wikipedia.org/wiki/Michigan 19. https://en.wikipedia.org/wiki/United_States 20. https://astronomy.com/news/observing/2021/03/observe-theres-a-new-nova-visible-in-cassiopeia 21. https://cdn.pixabay.com/photo/2019/09/04/08/24/cat-4451003_960_720.jpg 22. https://apod.nasa.gov/apod/ap210606.html 23. https://apod.nasa.gov/apod/archivepix.html 24. https://apod.nasa.gov/apod/lib/apsubmit2015.html 25. https://apod.nasa.gov/apod/lib/aptree.html 26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 27. https://apod.nasa.gov/apod/calendar/allyears.html 28. https://apod.nasa.gov/apod.rss 29. https://apod.nasa.gov/apod/lib/edlinks.html 30. https://apod.nasa.gov/apod/lib/about_apod.html 31. http://asterisk.apod.com/discuss_apod.php?date=210607 32. https://apod.nasa.gov/apod/ap210608.html 33. http://www.phy.mtu.edu/faculty/Nemiroff.html 34. http://www.phy.mtu.edu/ 35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 36. http://www.astro.umd.edu/ 37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 38. https://www.nasa.gov/about/highlights/HP_Privacy.html 39. https://astrophysics.gsfc.nasa.gov/ 40. https://www.nasa.gov/ 41. https://www.nasa.gov/centers/goddard/ 42. http://www.mtu.edu/