The Sun in X rays from NuSTAR
Explanation:
Why are the regions above sunspots so hot?
Sunspots themselves are a bit
cooler than the surrounding solar surface because the magnetic fields that create
them reduce convective heating.
It is therefore unusual that regions overhead -- even much higher up in the Sun's
corona -- can be hundreds of times hotter.
To help find the cause,
NASA directed the Earth-orbiting
Nuclear Spectroscopic Telescope
Array (NuSTAR)
satellite to point its very sensitive X-ray telescope at the Sun.
Featured above is the Sun in ultraviolet light,
shown
in a red hue as taken by the orbiting
Solar Dynamics Observatory (SDO).
Superimposed in false-colored green and blue is emission above sunspots detected
by
NuSTAR in different bands of
high-energy
X-rays,
highlighting regions of extremely
high temperature.
Clues about the Sun's atmospheric
heating
mechanisms may not only come from this initial image,
but future NuSTAR images aimed at finding hypothesized
nanoflares,
brief bursts of energy that may drive the unusual heating.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
