Predictions of stellar occultations by the main planetary satellites
Short Name:
voccdb.epn_core
Date:
19 Apr 2024 14:16:01
Publisher:
Paris Astronomical Data Centre
Description:
The VOccDB database provides prediction and parameters of stellar
occultations by the main planetary satellites. Observations of a
stellar occultations help to better determine the size and the shape
of the occulting body, as well as its astrometric position at the
milli-arcsecond level precision. Only the main moons of giant planets
Jupiter, Saturn, Uranus and Neptune are considered in the event
prediction database. Predictions are provided over period 2023-2032,
up to visual magnitude 12 for the biggest satellites, and magnitude 14
for other satellites. For each stellar occultation event prediction,
the database provides circumstances and observational data, date and
timing of the occultation, star position and magnitude, excepted
duration, etc.
Since 1973, the 18-cm lines of the OH radical have been
systematically observed in a number of comets with the Nançay radio
telescope. This allowed an evaluation of the cometary water production
rates and their evolution with time, as well as a study of several
physical processes: the excitation mechanisms of the OH radio lines,
the expansion of the cometary atmospheres, their anisotropy in
relation with non-gravitational forces, the Zeeman effect in relation
with the cometary magnetic field. The Nançay observations of 53
cometary apparitions between 1982 and 2009 are now organized in this
database.
The ephemeris were produced by simulating the ejection of meteoroids
from the sunlit hemisphere of cometary nuclei, typically from 0 to 3
au, followed by the propagation of orbits of meteoroids in the Solar
System, taking into account the gravity of the Sun, the 8 planets,
Pluto, and the Moon, as well as the radiation pressure and the
Poynting-Robertson drag. Note that asteroid parent bodies were
considered as active (i.e. comet-like bodies) even if they are not
active today. The showers are predicted when a planet enters a large
enough set of meteoroids, at a distance less than typically 0.01 au.
See Vaubaillon J., Colas F., Jorda L. 2005 A new method to predict
meteor showers. I. Description of the model, Astronomy and
Astrophysics, Volume 439/2 p.751-760, as well as: Vaubaillon J. 2017 A
confidence index for forecasting of meteor showers, Planetary and
Space Science, Volume 143 p.78-82