Solar-Radiation Heating Effects on 3200 Phaethon

Search for Activity in 3200 Phaethon

We present deep optical imaging of Geminid meteor stream parent 3200 Phaethon taken in search of low-level cometary activity (i.e., coma or dust trail). Although no unambiguous cometary behavior was observed, we find an upper limit on the object’s cometary mass-loss rate of Ṁlim 0:01 kg s . The corresponding active fraction (the fraction of the surface area that could consist of freely sublimat...

Recurrent Perihelion Activity in (3200) Phaethon

We present a study of planet-crossing asteroid (3200) Phaethon at three successive perihelia in 2009, 2010, and 2012, using the NASA STEREO spacecraft. Phaethon is clearly detected in 2009 and 2012, but not in 2010. In both former years, Phaethon brightened unexpectedly by ∼1 mag at large phase angles, inconsistent with the ∼1 mag of steady fading expected from a discrete, macroscopic body over...

An upper limit on gas production from 3200 Phaethon

Asteroid 3200 Phaethon resembles a comet in some ways, including a highly-eccentric orbit (e∼ 0.89) and a strong associated meteor shower (the Geminids). Yet this object has never been observed to exhibit any cometary activity, i.e., gas production. We observed 3200 Phaethon with the Caltech Submillimeter Observatory on two occasions, once while it was near its closest approach to Earth as it n...

Solar ultraviolet radiation effects on biological systems.

Thermodynamic analysis of a novel solar water heating system during low sun radiation in Iran

This paper reports a plenary thermodynamic model of a novel solar system for water heating in buildings. Energy and exergy analyses are used to characterize the exergy destruction rate in any component and calculate system overall efficiency. The system consists of a solar evaporator, a heat exchanger to produce hot water, and an auxiliary pump. A computer simulation program using EES software ...