全部 标题 作者
关键词 摘要

OALib Journal期刊
ISSN: 2333-9721
费用:99美元

查看量下载量

相关文章

更多...
Physics  2009 

Resolving the hot dust around HD69830 and eta Corvi with MIDI and VISIR

DOI: 10.1051/0004-6361/200911626

Full-Text   Cite this paper   Add to My Lib

Abstract:

Most of the known debris discs exhibit cool dust in regions analogous to the Edgeworth-Kuiper Belt. However, a rare subset show hot excess from within a few AU, which is often inferred to be transient. We examine 2 such sources to place limits on their location to help distinguish between different interpretations for their origin. We use MIDI on the VLTI to observe the debris discs around eta Corvi and HD69830 using baseline lengths from 44-130m. New VISIR observations of HD69830 at 18.7um are also presented. These observations are compared with disc models to place limits on disc size. The visibility functions measured with MIDI for both sources show significant variation with wavelength across 8-13um in a manner consistent with the disc flux being well resolved, notably with a dip at 10-11.5um due to the silicate emission feature. The average ratio of visibilities measured between 10-11.5um and 8-9um is 0.934+/-0.015 for HD69830 and 0.880+/-0.013 for eta Corvi over the 4 baselines for each source, a departure of 4 and 9sigma from that expected if the discs were unresolved. HD69830 is unresolved by VISIR at 18.7um. The combined limits from MIDI and 8m imaging constrain the warm dust to lie within 0.05-2.4AU for HD69830 and 0.16-2.98AU for eta Corvi. These results represent the first resolution in the mid-IR of dust around main sequence stars. The constraints placed on the location of the dust are consistent with radii predicted by SED modelling. Tentative evidence for a common position angle for the dust at 1.7AU with that at 150AU around eta Corvi, which might be expected if the hot dust is fed from the outer disc, demonstrates the potential of this technique for constraining the origin of the dust and more generally for the study of dust in the terrestrial regions of main sequence stars.

Full-Text

Contact Us

service@oalib.com

QQ:3279437679

WhatsApp +8615387084133