On the role of Type Ia supernovae in the second generation star
  formation in globular clusters
  By means of 3D hydrodynamic simulations, we study how Type Ia supernovae
(SNe) explosions affect the star formation history and the chemical properties
of second generation (SG) stars in globular clusters (GC). SG stars are assumed
to form once first generation asymptotic giant branch (AGB) stars start
releasing their ejecta; during this phase, external gas is accreted by the
system and SNe Ia begin exploding, carving hot and tenuous bubbles. Given the
large uncertainty on SNe Ia explosion times, we test two different values for
the 'delay time'. We run two different models for the external gas density: in
the low-density scenario with short delay time, the explosions start at the
beginning of the SG star formation, halting it in its earliest phases. The
external gas hardly penetrates the system, therefore most SG stars present
extreme helium abundances (Y > 0.33). The low-density model with delayed SN
explosions has a more extended SG star formation epoch and includes SG stars
with modest helium enrichment. On the contrary, the high-density model is
weakly affected by SN explosions, with a final SG mass similar to the one
obtained without SNe Ia. Most of the stars form from a mix of AGB ejecta and
pristine gas and have a modest helium enrichment. We show that gas from SNe Ia
may produce an iron spread of $\sim 0.14$ dex, consistent with the spread found
in about 20% of Galactic GCs, suggesting that SNe Ia might have played a key
role in the formation of this sub-sample of GCs.
