Astronomy UN2002: Introduction to Astrophysics II
Light Echoes - Jan 22
When a star has a bright outburst, the light may illuminate clouds
or sheets of interstellar dust in its vicinity and along the line of
sight to us. The arrival of the scattered light is delayed from
the arrival of the direct signal, resulting in apparent rings that
expand in time. Some of the more spectacular examples are illustrated
here.
Star V838 Monocerotis
Light Echoes from V838 Mon in 2002 from the Hubble Space Telescope, and
animation.
Supernova 1987A
Light Echoes from Supernova 1987A from the Anglo-Autralian Telescope
X-ray outburst of Soft Gamma-ray Repeater 1E 1547.0-5408, and animation.
X-ray scattering halo from a Soft Gamma-ray Repeater
outburst detected by the
Swift satellite on January 22, 2009.
Note the apparent expansion of the echo on successive days.
Black Hole X-ray Nova V404 Cyg
Swift satellite animation of X-ray scattering halo from the outburst of the black hole binary V404 Cyg on June 30 - July 4, 2015
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Updated: January 21, 2019