scholarly journals Circumstellar dust and circumstellar extinction curves

1995 ◽  
Vol 224 (1-2) ◽  
pp. 223-226 ◽  
Author(s):  
N. V. Voshchinnikov ◽  
F. J. Molster ◽  
P. S. Th�
1995 ◽  
pp. 223-226
Author(s):  
N. V. Voshchinnikov ◽  
F. J. Molster ◽  
P. S. Thé

1999 ◽  
Vol 515 (1) ◽  
pp. 191-195 ◽  
Author(s):  
Robin Ciardullo ◽  
George H. Jacoby

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Mudumba Parthasarathy ◽  
Tadafumi Matsuno ◽  
Wako Aoki

Abstract From Gaia DR2 data of eight high-velocity hot post-AGB candidates, LS 3593, LSE 148, LS 5107, HD 172324, HD 214539, LS IV −12 111, LS III +52 24, and LS 3099, we found that six of them have accurate parallaxes which made it possible to derive their distances, absolute visual magnitudes (MV) and luminosity (log L/L⊙). All the stars except LS 5107 have an accurate effective temperature (Teff) in the literature. Some of these stars are metal poor, and some of them do not have circumstellar dust shells. In the past, the distances of some stars were estimated to be 6 kpc, which we find to be incorrect. The accurate Gaia DR2 parallaxes show that they are relatively nearby, post-AGB stars. When compared with post-AGB evolutionary tracks we find their initial masses to be in the range 1 M⊙ to 2 M⊙. We find the luminosity of LSE 148 to be significantly lower than that of post-AGB stars, suggesting that this is a post-horizontal-branch star or post-early-AGB star. LS 3593 and LS 5107 are new high-velocity hot post-AGB stars from Gaia DR2.


2008 ◽  
Vol 683 (2) ◽  
pp. L171-L174 ◽  
Author(s):  
John P. Wisniewski ◽  
Mark Clampin ◽  
Karen S. Bjorkman ◽  
Richard K. Barry

Icarus ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 168-179 ◽  
Author(s):  
A. Lecavelier des Etangs ◽  
H. Scholl ◽  
F. Roques ◽  
B. Sicardy ◽  
A. Vidal-Madjar
Keyword(s):  

2020 ◽  
Vol 641 ◽  
pp. A75
Author(s):  
T. Löhne

The excess emission seen in spectral energy distributions (SEDs) is commonly used to infer the properties of the emitting circumstellar dust in protoplanetary and debris discs. Most notably, dust size distributions and details of the collision physics are derived from SED slopes at long wavelengths. This paper reviews the approximations that are commonly used and contrasts them with numerical results for the thermal emission. The inferred size distribution indexes p are shown to be greater and more sensitive to the observed sub(mm) spectral indexes, αmm, than previously considered. This effect results from aspects of the transition from small grains with volumetric absorption to bigger grains that absorb and emit near to their surface, controlled by both the real and the imaginary part of the refractive index. The steeper size distributions indicate stronger size-dependence of material strengths or impact velocities or, otherwise, less efficient transport or erosion processes. Strong uncertainties remain because of insufficient knowledge of the material composition, porosity, and optical properties at long wavelengths.


Author(s):  
Sun Kwok ◽  
Bruce J. Hrivnak ◽  
Thomas R. Geballe
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document