A three-dimensional map of the hot Local Bubble using diffuse
  interstellar bands
  The Solar System is located within a low-density cavity, known as the Local
Bubble, which appears to be filled with an X-ray emitting gas at a temperature
of 10$^6$ K. Such conditions are too harsh for typical interstellar atoms and
molecules to survive. There exists an enigmatic tracer of interstellar gas,
known as Diffuse Interstellar Bands (DIB), which often appears as absorption
features in stellar spectra. The carriers of these bands remain largely
unidentified. Here we report the three-dimensional structure of the Local
Bubble using two different DIB tracers ($\lambda$5780 and $\lambda$5797), which
reveals that DIB carriers are present within the Bubble. The map shows low
ratios of $\lambda$5797/$\lambda$5780 inside the Bubble compared to the
outside. This finding proves that the carrier of the $\lambda$5780 DIB can
withstand X-ray photo-dissociation and sputtering by fast ions, where the
carrier of the $\lambda$5797 DIB succumbs. This would mean that DIB carriers
can be more stable than hitherto thought and that the carrier of the
$\lambda$5780 DIB must be larger than that of the $\lambda$5797 DIB.
Alternatively, small-scale denser (and cooler) structures that shield some of
the DIB carriers must be prevalent within the Bubble, implying that such
structures may be an intrinsic feature of supernova-driven bubbles.
