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Hi all, V838 Mon is indeed an interesting object. What are the main arguments against it being a "born-again" type, or like star (e.g. V434 Sgr or V605 Aql)? V838 Mon has a light curve that sure looks a lot like our "born-again", models. Cheers, Tim Lawlor At 06:16 PM 9/23/2003 +1000, Alon Retter wrote: >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 ***************************************************************** Timothy M. Lawlor, Assistant Professor and Director, Friedman Observatory Department of Physics Penn State Wilkes-Barre PO Box PSU Lehman, Pa 18627 ***************************************************************** HOME PAGE http://vsnet.personal.psu.edu/faculty/t/m/tml10/ FRIEDMAN OBSERVATORY http://vsnet.wb.psu.edu/observatory Phone: 570 675-9278 FAX: 570 674-9072
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