by APOD Robot » Sun Jun 26, 2022 4:05 am
Light Echoes from V838 Mon
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star
V838 Mon's outer surface
suddenly greatly expanded with the result that it became one of the
brighter stars in the
Milky Way Galaxy in early 2002. Then, just as suddenly,
it shrunk and faded. A
stellar flash like this had never been seen before --
supernovas and
novas expel matter out into space. Although the
V838 Mon flash appears to expel material into space, what is seen in the
featured image from the
Hubble Space Telescope is actually an outwardly expanding
light echo of the original flash. In a
light echo, light from the flash is reflected by successively
more distant surfaces in the complex array of ambient
interstellar dust that already surrounded the star.
V838 Mon lies about 20,000
light years away toward the
constellation of the unicorn (
Monoceros), while the
light echo above spans about six
light years in diameter.
[url=https://apod.nasa.gov/apod/ap220626.html] [img]https://apod.nasa.gov/apod/calendar/S_220626.jpg[/img] [size=150]Light Echoes from V838 Mon[/size][/url]
[b] Explanation: [/b] What caused this outburst of V838 Mon? For reasons unknown, star [url=https://en.wikipedia.org/wiki/V838_Monocerotis]V838 Mon[/url]'s outer surface [url=https://media.istockphoto.com/photos/curious-cat-face-peeps-out-picture-id1202689418?k=20&m=1202689418&s=612x612&w=0&h=xOIn_9jq1icnUcpdr6-G8n9RRQHZA5f9X5UcGBQ3z_0=]suddenly greatly expanded[/url] with the result that it became one of the [url=https://en.wikipedia.org/wiki/List_of_most_luminous_stars]brighter stars[/url] in the [url=https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/]Milky Way Galaxy[/url] in early 2002. Then, just as suddenly, [url=https://ui.adsabs.harvard.edu/abs/2005A%26A...436.1009T/abstract]it[/url] shrunk and faded. A [url=https://www.aanda.org/articles/aa/full_html/2014/09/aa24458-14/aa24458-14.html]stellar flash[/url] like this had never been seen before -- [url=https://heasarc.gsfc.nasa.gov/docs/snr.html]supernovas[/url] and [url=https://youtu.be/zYmd8EETy74]novas[/url] expel matter out into space. Although the [url=https://apod.nasa.gov/apod/ap140617.html]V838 Mon[/url] flash appears to expel material into space, what is seen in the [url=https://hubblesite.org/contents/media/images/3867-Image]featured image[/url] from the [url=https://apod.nasa.gov/apod/ap010806.html]Hubble Space Telescope[/url] is actually an outwardly expanding [url=https://apod.nasa.gov/apod/ap971023.html]light echo[/url] of the original flash. In a [url=https://en.wikipedia.org/wiki/Light_echo]light echo[/url], light from the flash is reflected by successively [url=https://viewspace.org/interactives/unveiling_invisible_universe/variable_stars/v838_monocerotis]more distant surfaces[/url] in the complex array of ambient [url=https://apod.nasa.gov/apod/ap990509.html]interstellar dust[/url] that already surrounded the star. [url=https://slate.com/technology/2013/12/when-stars-collide-the-enigmatic-beauty-of-v838-mon.html]V838 Mon[/url] lies about 20,000 [url=https://chandra.harvard.edu/photo/cosmic_distance.html]light years[/url] away toward the [url=https://apod.nasa.gov/apod/ap030401.html]constellation[/url] of the unicorn ([url=https://en.wikipedia.org/wiki/Monoceros]Monoceros[/url]), while the [url=http://www.aavso.org/vsots_v838mon]light echo[/url] above spans about six [url=https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html]light years[/url] in diameter.
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