2008A&A...481..769B

Kaastra Jelle (private communication) noted differences between the incident soft X-ray spectrum of Sirius B given in Table 3 of Beuermann et al. (2006A&A...458..541B), his own version, whereas the similarly derived HZ43A spectra agree excellently. The differences are caused by two trivial errors in our paper and by a non-trivial systematic difference in the model atmosphere spectra created with the TLUSTY code used by Kaastra and TMAP used by us. erroneously quotes the parameters of the simultaneous fit to the LETG+HRC spectra of HZ43A Table2, Sirius B, for logg RXJ1856-37 (Sirius B)=8.55 instead of the preferred logg=8.60. The latter gives T_eff=24897±115K for Sirius B and T_eff=51111±660K for HZ43A, which is only 26K and 15K lower than for logg=8.55. All other parameters of the simultaneous fit change only by a minute 0.03-0.11%. Table3 incorrectly gives the Sirius B fluxes without interstellar absorption, which raises them noticeably at longer wavelengths. We enclose the revised table for logg=8.60(Sirius B) and logg=7.90(HZ43A). For logg=8.55, the fluxes of Sirius B at 60, 100, and 160Å change by -1.4%, +0.2%, and -0.2%, respectively. None of our conclusions is affected. non-trivial difference in the model fluxes results from different assumptions on the level dissolution by pressure ionization in TLUSTY The, Level dissolution is unimportant in the hot atmosphere of HZ43A explaining why the discrepancy only exists for Sirius B. The unsolved problem of level dissolution is discussed by Rauch (2008A&A...481..807R) TMAP.