Monthly Notices Of The Royal Astronomical Society
New long Chandra grating observations of the O supergiant ζ Pup show not only a brightening of the X-ray emission line flux of 13 per cent in the 18 yr since Chandra’s first observing cycle, but also clear evidence – at more than 4σ significance – of increased wind absorption signatures in its Doppler-broadened line profiles. We demonstrate this with non-parametric analysis of the profiles as well as Gaussian fitting and then use line-profile model fitting to derive a mass-loss rate of 2.47 ± 0.09 × 10−6[Math Processing Error], which is a 40 per cent increase over the value obtained from the cycle 1 data. The increase in the individual emission line fluxes is greater for short-wavelength lines than long-wavelength lines, as would be expected if a uniform increase in line emission is accompanied by an increase in the wavelength-dependent absorption by the cold wind in which the shock-heated plasma is embedded.
radiative transfer, stars: early-type, stars individual: ζ Puppis, stars: massive, stars: mass-loss, stars: winds, outflows, X-rays: stars
David H. Cohen; Jiaming Wang , '22; V. Petit; M. A. Leutenegger; L. Dakir; C. Mayhue , '23; and A. David-Uraz.
"Chandra Spectral Measurements Of The O Supergiant ζ Puppis Indicate A Surprising Increase In The Wind Mass-Loss Rate Over 18 Yr".
Monthly Notices Of The Royal Astronomical Society.