dc.contributor.author | Nordhaus, J. | |
dc.contributor.author | Minchev, I. | |
dc.contributor.author | Sargent, B. | |
dc.contributor.author | Forrest, W. | |
dc.contributor.author | Blackman, Eric | |
dc.contributor.author | De Marco, O. | |
dc.contributor.author | Kastner, Joel | |
dc.contributor.author | Balick, B. | |
dc.contributor.author | Frank, A. | |
dc.date.accessioned | 2009-02-23T15:51:08Z | |
dc.date.available | 2009-02-23T15:51:08Z | |
dc.date.issued | 2008 | |
dc.identifier.citation | Monthly Notices of the Royal Astronomical Society, Volume 388 Issue 2, Pages 716 - 722 | en_US |
dc.identifier.uri | http://hdl.handle.net/1850/8457 | |
dc.description | RIT community members may access full-text via RIT Libraries licensed databases: http://library.rit.edu/databases/ | |
dc.description.abstract | HD 179821 is an evolved star of unknown progenitor mass range (either post-
Asymptotic Giant Branch or post-Red Supergiant) exhibiting a double peaked spectral
energy distribution (SED) with a sharp rise from ∼ 8−20 μm. Such features have been
associated with ejected dust shells or inwardly truncated circumstellar discs. In order to
compare SEDs from both systems, we employ a spherically symmetric radiative transfer
code and compare it to a radiative, inwardly truncated disc code. As a case study, we
model the broad-band SED of HD 179821 using both codes. Shortward of 40 μm, we
find that both models produce equivalent fits to the data. However, longward of 40 μm,
the radial density distribution and corresponding broad range of disc temperatures produce
excess emission above our spherically symmetric solutions and the observations.
For HD 179821, our best fit consists of a Teff = 7000 K central source characterized by
V ∼ 1.95 and surrounded by a radiatively driven, spherically symmetric dust shell. The
extinction of the central source reddens the broad-band colours so that they resemble
a Teff = 5750 K photosphere. We believe that HD 179821 contains a hotter central
star than previously thought. Our results provide an initial step towards a technique
to distinguish geometric differences from spectral modeling. | en_US |
dc.language.iso | en_US | en_US |
dc.publisher | Wiley-Blackwell | en_US |
dc.relation.ispartofseries | vol. 388 | en_US |
dc.relation.ispartofseries | no. 2 | en_US |
dc.relation.ispartofseries | pp. 716-722 | en_US |
dc.subject | Circumstellar matter | en_US |
dc.subject | Infrared: general | en_US |
dc.subject | Planetary nebulae: general | en_US |
dc.subject | Radiative transfer | en_US |
dc.subject | Stars: AGB and post-AGB | en_US |
dc.subject | Submillimetre | en_US |
dc.title | Towards a spectral technique for determining material geometry around evolved stars: Application to HD 179821 | en_US |
dc.type | Article | en_US |
dc.identifier.url | http://dx.doi.org/10.1111/j.1365-2966.2008.13428.x | |