%0 Journal Article
%T Evidence for magnetic activity at starbirth: a powerful X-ray flare from the Class 0 protostar HOPS 383
%A David A. Principe
%A Joel H. Kastner
%A Kenji Hamaguchi
%A Nicolas Grosso
%J -
%D 2020
%R 10.1051/0004-6361/202038185
%X <i>Context.<i/> Class 0 protostars represent the earliest evolutionary stage of solar-type stars, during which the majority of the system mass resides in an infalling envelope of gas and dust and is not yet in the central, nascent star. Although X-rays are a key signature of magnetic activity in more evolved protostars and young stars, whether such magnetic activity is present at the Class 0 stage is still debated.<i>Aims.<i/> We aim to detect a bona fide Class 0 protostar in X-rays.<i>Methods.<i/> We observed HOPS 383 in 2017 December in X-rays with the <i>Chandra<i/> X-ray Observatory (¡«84 ks) and in near-infrared imaging with the Southern Astrophysical Research telescope.<i>Results.<i/> HOPS 383 was detected in X-rays during a powerful flare. This hard (<i>E<i/>£¿> £¿2 keV) X-ray counterpart was spatially coincident with the northwest 4 cm component of HOPS 383, which would be the base of the radio thermal jet launched by HOPS 383. The flare duration was ¡«3.3 h; at the peak, the X-ray luminosity reached ¡«4£¿¡Á£¿10<sup>31<sup/> erg s<sup>£¿1<sup/> in the 2£¿8 keV energy band, a level at least an order of magnitude larger than that of the undetected quiescent emission from HOPS 383. The X-ray flare spectrum is highly absorbed (<i>N<i/><sub>H<sub/>£¿¡«£¿7£¿¡Á£¿10<sup>23<sup/> cm<sup>£¿2<sup/>), and it displays a 6.4 keV emission line with an equivalent width of ¡«1.1 keV, arising from neutral or low-ionization iron.<i>Conclusions.<i/> The detection of a powerful X-ray flare from HOPS 383 constitutes direct proof that magnetic activity can be present at the earliest formative stages of solar-type stars
%U https://www.aanda.org/articles/aa/full_html/2020/06/aa38185-20/aa38185-20.html