Astronomy & Astrophysics

All Tables

Table 1: Stellar parameters and known fluxes of our target sample. V-band magnitudes and the IRAS 12 $\mu$ m fluxes are taken from the SIMBAD database. $T_{{\rm adopted}}$ and (log g) $_{{\rm adopted}}$ list the temperature and surface acceleration which we used for the Kurucz atmosphere models. The mm-flux of HD 41511 was measured in Jura et al. (2001). Stellar ages: (1) Zuckerman & Song (2004) quote 300 Myr with a caveat (methods used: X-ray emission and lithium age); Decin et al. (2000) give 3500 Myr as an upper range (isochrones); (2) Song et al. (2001, evolutionary tracks); (3) Song et al. (2001, evolutionary tracks); (4) Meyer et al. (2001, estimation from evolutionary tracks); (5) Zuckerman & Song (2004); (6) Lachaume et al. (1999, isochrones and Ca lines). The distances are taken from (7) Decin et al. (2000); (8) Chen & Jura (2001); (9) Fekel et al. (2002); (10) Jura et al. (2001); (11) Meyer et al. (2001); (12) Zuckerman et al. (2001); (13) Jourdain de Muizon et al. (1999).
Table 2: Results from TIMMI2 photometry and spectroscopy as well as SIMBA observations are merged in this table. The airmass and TIMMI2 integration time refer to N-band spectroscopy. Mid-IR photometry was obtained in the N11.9 passband ( $\lambda_0= 11.6~\mu$ m). Errors represent the accuracy of this aperture photometry and do not necessarily include the uncertainty which measurements on different nights may introduce due to atmospheric fluctuations (errors caused by the latter one might amount up to 10% for the fainter sources).
Table 3: Mass ratios derived from the model fits to the N-band spectra: large to small amorphous olivine (m_2.0/m_0.1), crystalline to amorphous silicates ( $m_{{\rm forst}}$ / $m_{{\rm sil}}$ ) and SiO₂ to silicates ( $m_{{\rm SiO_{2}}}$ / $m_{{\rm sil}}$ ).
Table 4: (1) Upper limits for circumstellar dust masses obtained from our measurements at 1200 $\mu$ m and assuming a $T_{{\rm dust}} = 50$ K. HD 40932 was not considered, since the TIMMI2 spectra together with the SED had shown the non-existence of CS matter. (2) Reference dust masses re-calculated with $T_{{\rm dust}} = 50$ K. See Sheret et al. (2004) for their actual masses.