This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Konstantin V. Getman, Department of Astronomy & Astrophysics, Pennsylvania State University;
(2) Agnes Kospal, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, E¨otv¨os Lor´and Research Network (ELKH), MTA Centre of Excellence, Max Planck Institute for Astronomy, and ELTE E¨otv¨os Lor´and University, Institute of Physics;
(3) Nicole Arulanantham, Space Telescope Science Institute;
(4) Dmitry A. Semenov, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences;
(5) Grigorii V. Smirnov-Pinchukov, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences;
(6) Sierk E. van Terwisga, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences.
We conducted three observations of the periastron passages of DQ Tau using X-ray telescopes: in 2010 (Getman et al. 2011), 2021 (Getman et al. 2022a), and 2022 (current study). Notably, significant X-ray flares were detected on all three occasions.
In Figure 8, we compare the duration, peak X-ray luminosity, and energetics of these DQ Tau flares with numerous large X-ray flares produced by young stars, as studied by Getman et al. (2008, also known as COUP flares) and Getman & Feigelson (2021, also known as MYStIX/SFiNCs flares). In Figure 8, we only include the “main” DQ Tau X-ray flares that occur roughly within the orbital phase range of (0.95 − 1.05). However, it is important to note that more X-ray flaring events of comparable energetics are present within the (1.05 − 1.2) orbital phase range (see Figure 2 here and Figure 1 in Getman et al. (2022a)).
It is also noteworthy that somewhat different methodologies for flare detection and analysis were employed in Getman et al. (2008) and Getman & Feigelson (2021), due to distinct scientific objectives pursued in these two papers
As a result, Getman et al. (2008) reported the rise and decay timescales, flare peak X-ray luminosities, but no energies for the COUP flares, while Getman & Feigelson (2021) reported only total flare durations (with no differentiation between rise and decay), flare peak Xray luminosities, and energies for the MYStIX/SFiNCs flares.
Consequently, the rise and decay timescales, as well as flare peak X-ray luminosities, are compared between the DQ Tau and COUP flares (see Figure 8a and b), while the flare durations, peak luminosities, and energies are compared between the DQ Tau and MYStIX/SFiNCs flares (see Figure 8c and d).
Figure 8 illustrates that the DQ Tau flares lie within the loci of the COUP and MYStIX/SFiNCs flares, albeit having relatively long durations and relatively low peak flare X-ray luminosities. This places them at the sensitivity limit border of the COUP and MYStIX/SFiNCs flare surveys.