Volume 638, June 2020
|Number of page(s)||12|
|Section||Letters to the Editor|
|Published online||15 June 2020|
Letter to the Editor
Evidence for magnetic activity at starbirth: a powerful X-ray flare from the Class 0 protostar HOPS 383
Aix-Marseille Univ, CNRS, CNES, LAM, Marseille, France
2 CRESST II and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD, USA
3 Department of Physics, University of Maryland, Baltimore County, Baltimore, MD, USA
4 Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA, USA
5 Center for Imaging Science, School of Physics & Astronomy, and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, Rochester, NY, USA
Accepted: 2 May 2020
Context. 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.
Aims. We aim to detect a bona fide Class 0 protostar in X-rays.
Methods. We observed HOPS 383 in 2017 December in X-rays with the Chandra X-ray Observatory (∼84 ks) and in near-infrared imaging with the Southern Astrophysical Research telescope.
Results. HOPS 383 was detected in X-rays during a powerful flare. This hard (E > 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 × 1031 erg s−1 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 (NH ∼ 7 × 1023 cm−2), and it displays a 6.4 keV emission line with an equivalent width of ∼1.1 keV, arising from neutral or low-ionization iron.
Conclusions. 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.
Key words: stars: flare / stars: individual: HOPS 383 / stars: low-mass / stars: magnetic field / stars: protostars / X-rays: stars
© N. Grosso et al. 2020
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.