Browsing by Subject "size distributions"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Extreme Conditions in a Close Analog to the Young Solar System: Herschel Observations of Epsilon Eridani(2014-08) Greaves, J. S.; Sibthorpe, B.; Acke, B.; Pantin, E. E.; Vandenbussche, B.; Olofsson, G.; Dominik, C.; Barlow, M. J.; Bendo, G. J.; Blommaert, Jadl; Brandeker, A.; de Vries, B. L.; Dent, W. R. F.; Di Francesco, J.; Fridlund, M.; Gear, W. K.; Harvey, Paul M.; Hogerheijde, M. R.; Holland, W. S.; Ivison, R. J.; Liseau, R.; Matthews, B. C.; Pilbratt, G. L.; Walker, H. J.; Waelkens, C.; Harvey, Paul M.Far-infrared Herschel images of the is an element of Eridani system, seen at a fifth of the Sun's present age, resolve two belts of debris emission. Fits to the 160 mu m PACS image yield radial spans for these belts of 12-16 and 54-68 AU. The south end of the outer belt is approximate to 10% brighter than the north end in the PACS+SPIRE images at 160, 250, and 350 mu m, indicating a pericenter glow attributable to a planet "c" From this asymmetry and an upper bound on the offset of the belt center, this second planet should be mildly eccentric (e(c) approximate to 0.03-0.3). Compared to the asteroid and Kuiper Belts of the young Sun, the is an element of Eri belts are intermediate in brightness and more similar to each other, with up to 20 km sized collisional fragments in the inner belt totaling approximate to 5% of an Earth mass. This reservoir may feed the hot dust close to the star and could send many impactors through the Habitable Zone, especially if it is being perturbed by the suspected planet is an element of Eri b, at semi-major axis approximate to 3 AU.Item Multi-Epoch Observations Of Hd 69830: High-Resolution Spectroscopy And Limits To Variability(2011-12) Beichman, Charles A.; Lisse, C. M.; Tanner, A. M.; Bryden, G.; Akeson, R. L.; Ciardi, David R.; Boden, Andrew F.; Dodson-Robinson, Sarah E.; Salyk, Colette; Wyatt, M. C.; Dodson-Robinson, Sarah E.; Salyk, ColetteThe main-sequence solar-type star HD 69830 has an unusually large amount of dusty debris orbiting close to three planets found via the radial velocity technique. In order to explore the dynamical interaction between the dust and planets, we have performed multi-epoch photometry and spectroscopy of the system over several orbits of the outer dust. We find no evidence for changes in either the dust amount or its composition, with upper limits of 5%-7% (1 sigma per spectral element) on the variability of the dust spectrum over 1 year, 3.3% (1 sigma) on the broadband disk emission over 4 years, and 33% (1 sigma) on the broadband disk emission over 24 years. Detailed modeling of the spectrum of the emitting dust indicates that the dust is located outside of the orbits of the three planets and has a composition similar to main-belt, C-type asteroids in our solar system. Additionally, we find no evidence for a wide variety of gas species associated with the dust. Our new higher signal-to-noise spectra do not confirm our previously claimed detection of H(2)O ice leading to a firm conclusion that the debris can be associated with the break-up of one or more C-type asteroids formed in the dry, inner regions of the protoplanetary disk of the HD 69830 system. The modeling of the spectral energy distribution and high spatial resolution observations in the mid-infrared are consistent with a similar to 1 AU location for the emitting material.