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| Paper: |
Giant Eruption of the Extremely Metal-Poor LBV in DDO 68 |
| Volume: |
510, Stars: From Collapse to Collapse |
| Page: |
484 |
| Authors: |
Perepelitsyna, Y. A.; Pustilnik, S. A. |
| Abstract: |
Understanding the evolution of massive stars with metallicities much lower than that of the Sun (e.g., Z<Z☉/30) is crucial for correct modelling of processes in the early Universe, including formation and evolution of first galaxies. The lack of such stars in the nearby galaxies makes, however, this task very difficult and requires postponing this research until extremely large telescopes (ELTs) are in operation. Meantime, selection of good targets for future ELT research becomes actual. Here we present one of such important targets. The unusual void galaxy DDO68 has several star-forming (SF) regions with the gas metallicity Z = Z☉/35 [12+log(O/H)=7.14]. In 2008, we discovered a luminous blue variable (LBV) star in its HII-region Knot 3. We present the LBV's V-band lightcurve for the time range of 1988 to 2016 using both our new and published data for Knot 3 brightness as well as the archive data from eleven telescopes. The prerequisite is an accurate estimate of the ‘minimal' (non-variable) V-band light for the Knot 3 underlying HII region. Its subtraction from the variable light of Knot 3 allows us to determine the full amplitude of the LBV variability at the level of δV ≳4m. This implies that the LBV has experienced a very rare event of a giant eruption during the years 2008–2011. |
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