SearcharxivSearch

arXiv · 0811.2265

Six Hot Topics in Planetary Astronomy

Abstract

Six hot topics in modern planetary astronomy are described: 1) lightcurves and densities of small bodies 2) colors of Kuiper belt objects and the distribution of the ultrared matter 3) spectroscopy and the crystallinity of ice in the outer Solar system 4) irregular satellites of the giant planets 5) the Main Belt Comets and 6) comets and meteor stream parents.

Explore related subjects

Keep this discovery

BibTeXRIS

David Jewitt. 2008-11-14. Six Hot Topics in Planetary Astronomy. https://arxiv.org/abs/0811.2265

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Grand Unification II: Hot Accretion and AGN Jets

We show that a quasi-spherical (QS) hot accretion flow is expected to operate in all SMBHs, with its rate being capped at dot m_QS,max~0.001 (M/1E8Msun) in units of the Eddington rate. It is then proposed that AGN jet power is proportional to the product of the hot accretion rate and a SMBH spin-dependent efficiency for energy extraction in the form of jets. Predictions from this model include (1) while radio jets should emerge from all SMBHs, the maximum jet power goes with SMBH mass approximately as 1E43.6(M/1E8Msun)^{2}erg/s, (2) even although there are two separate underlying populations of radio-quiet (RQ) and radio-loud (RL) AGNs, any bimodality in the observed AGN radio loudness distribution is likely due to a selection effect, such as some imposed optical magnitude limits, (3) the RL fraction of quasars is expected to decrease with redshift in the cold dark matter model, (4) host galaxies of RQ and RL quasars should be drawn from the same underlying elliptical galaxy population, although RL quasars may have SMBHs that are somewhat more massive than their RQ counterparts and RL quasars may reside predominantly in core elliptical galaxies, (5) RL low-luminosity AGNs and LINERs may represent the long, declining "trailing" phase following the initial, more luminous AGN phase, (6) a broad anti-correlation between radio- loudness and disk accretion rate is expected, (7) RL AGNs may be expected to be more abundant in Type Ia supernovae than RQ AGNs, (8) among RL AGNs a correlation between radio power and clustering strength is predicted, and (9) RQ and RL AGNs should have, on average, similar IR-optical-UV properties. ~

astro-ph

Halo Spacetime

It is shown that constant galactic rotation curves require a logarithmic potential in both newtonian and relativistic theory. In newtonian theory the density vanishes asymptotically, but there are a variety of possibilities for perfect fluid einstein theory.

astro-ph

Radial velocity-acceleration curve analysis of the spectroscopic binary stars by the nonlinear regression

We will introduce a new method to derive the orbital elements of the spectroscopic binary stars. Fitting the adopted radial velocity curves on the measured experimental data, the corresponding radial acceleration data are obtained. The orbital parameters are estimated by the nonlinear least squares of the radial velocity-acceleration curves. This method is implemented for the three double line spectroscopic binary systems RZ CAS, CC Cas and V1130 Tau. Numerical calculations show that the result are in good agreement with the those obtained by others using the method of Lehmann-Filhés.

astro-ph