My first Magazine Sky & Telescope - 02.2019 | Page 50

FEBRUARY 2019 OBSERVING
Celestial Calendar by S. N. Johnson-Roehr
Echoes from
a Variable Star
RS Puppis continues to delight
astronomers more than 120 years
after its true nature was discovered.
The thick cloak of nebulosity that surrounds RS Puppis makes the star unique among Cepheid variables.
These dust clouds reveal “light echoes” of the star’s pulsations. The echoes have to travel farther, so they
arrive at Earth later than does the starlight.
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FE B RUA RY 2 019 • SK Y & TELESCOPE