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Dear Ulisse, Thank you for the clarifications. I agree with you that the distance is still badly constrained and further work still needs to be done, but I think that it is likely above ~8 Kpc. The B star may well be a background star, but it is still not a problem for our model as planets have been observed in binary systems. What do you think about our suggestion that the eruption of V838 Mon was caused by an expanding giant that swallowed of 3 planets? Regards, Alon ----------------------------------------------------------------------- Dr. Alon Retter Tel. (work) +61-2-9351-4058 School of Physics Fax (work) +61-2-9351-7726 University of Sydney ------------------------------------------- Sydney, 2006 "As a scientist I don't believe myself, so Australia why should I believe you?" (A.R. 1965-2085) http://vsnet.physics.usyd.edu.au/~retter/ ----------------------------------------------------------------------- On Tue, 23 Sep 2003, Ulisse Munari wrote: > the picture is far more complex than the below two mails could suggest. > Furthermore, some published work is wrongly cited/interpreted. > > 1. we never claim (A&A Lett 389, L51) there was an F-type star in V838 Mon > prior to its explosion, only that its combined optical-IR colors > resembled those of a F0 star *IF* the extinction is E(B-V)=0.5 and *IF* > the extinction law is the one valid for the diffuse interstellar medium > (the one characterized by R_V = 3.1). The distance to the star plays no > role here. The F0 colors pertained to the combined light of the > components of the binary system. > > 2. the distance of 790 pc has been direved under the assumption of a > flat scattering disk seen pole-on and cetered on the star. Other > assumptions (flat slab of interstellar material, sferically symmetric > circumstellar material centered on the star) have lead to different > published distances, 1.8, 3.5, >6 kpc. Coming announced astro-ph > entries should deal with even more complex scattering dust geometries. > > 3. polarimetry suggests a distance not exceeding a few kpc. > > 4. there is a B3V star still sthere, and its spectrophotometric parallax > is 10.5 kpc (IAUC 8005) if the calibration for nearby B3V stars holds > for B3V stars at the edge of the galactic thin disk, where the > metallicity is -0.5 dex lower than in the solar neighborhood. And if > the B3V star in V838 Mon is a genuine B3V star and if the reddening > is is E(B-V)=0.5 and if the extinction follow the stardard R_V = 3.1 > law. > > Ulisse Munari, Padova and Asiago Observatories
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