J/A+A/485/293 Events of Saturn satellites during 2009 equinox (Arlot+, 2008)
Predictions of the events of the satellites of Saturn during the 2009 equinox.
Arlot J.E., Thuillot W.
<Astron. Astrophys. 485, 293 (2008)>
=2008A&A...485..293A 2008A&A...485..293A
ADC_Keywords: Planets ; Positional data
Keywords: astrometry - occultations - eclipses - celestial mechanics -
planets and satellites: individual
Abstract:
The Saturnian equinox will occur in 2009; i.e., the Sun (and the
Earth, very close to the Sun as seen from Saturn) will be in the
equatorial plane of Saturn. Eclipses of the satellites by Saturn or
mutual eclipses and occultations will occur among the seven first
satellites orbiting in the Saturnian equatorial plane. This paper
provides predictions of these events, along with information useful
for observing them. Such events are uncommon, since they only occur
every 15 years during the Saturnian equinox. The present dynamical
models of motion of the Saturnian satellites include many effects on
their motion. One needs accurate observations, such as mutual events,
to determine all the relevant parameters.
Description:
For these predictions, we used the best theoretical models of the
motion of the satellites, since the prediction of events is very
sensitive to the accuracy of the relative calculated positions of the
satellites.
Therefore, we encourage professional and amateur astronomers to join
the observers network to get as many observations as possible. Data on
the predictions of the events and interactive software for their
visibility are available on the web server of the IMCCE
(www.imcce.fr/phemu09).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tab4-7.dat 138 123 *List of easily observable mutual events
occurring from October 2, 2008 to June 18, 2010
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Note on tab4-7.dat: The dates are provided in terrestrial time (TT) since
the UTC for this period is not yet available. The difference TT-UTC
will, however, be near 65 seconds in 2009. Observations will be
recorded with reference to UTC.
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See also:
J/AJ/103/983 : Stellar occultation candidates of Saturn (Bosh+, 1992)
J/A+AS/139/305 : Position of Saturn's satellites (1982-1988) (Veiga+, 1999)
J/A+AS/121/65 : 1990-1994 Saturn's satellites astrometry (Harper+ 1997)
J/A+A/380/727 : 1995 Saturnian satellite observations (Vienne+, 2001)
J/A+A/400/1095 : 1995-1999 CCD observation of Saturnian satellite (Veiga+ 2003)
J/A+AS/136/257 : Saturn's satellites in 1995/97 (Harper+ 1999)
J/A+A/422/377 : 1997-2000 Saturn's satellites astrometry (Qiao+, 2004)
Byte-by-byte Description of file: tab4-7.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "Y/M/D" Date Date of the maximum of the event
12- 14 A3 --- Event Nature of the event (1)
16 A1 --- Type [PAT] Type of eclipse (2)
18- 25 A8 "h:m:s" TimeBp Time in TT of the beginning of the eclipse by
the penumbra (only for eclipses)
27- 34 A8 "h:m:s" TimeBs Time in TT of the beginning of the eclipse by
the shadow or beginning of the occultation
36- 43 A8 "h:m:s" TimeBt Time in TT of the beginning of totality
(only for total events)
45- 52 A8 "h:m:s" TimeM Time in TT of the maximum of the event
54- 61 A8 "h:m:s" TimeM2 Time in TT of the maximum of the event
calculated with Do93 ephemeris
63- 70 A8 "h:m:s" TimeEt Time in TT of the end of totality
(only for total events)
72- 79 A8 "h:m:s" TimeEs Time in TT of the end of the eclipse by the
shadow or end of the occultation
81- 88 A8 "h:m:s" TimeEp Time in TT of the end of the eclipse by the
penumbra (only for eclipses)
90- 94 F5.3 --- Drop [0,1] Flux drop in the V-band (3)
96-100 F5.3 --- Drop1 [0,1] Flux drop with the same albedoes for all
the implied satellites (3)
102-107 F6.3 mag mDrop Magnitude drop with the same albedoes for all
the implied satellites (4)
109-114 F6.3 mag mDrop2 Magnitude drop with the same albedoes for all
the implied satellites calculated with Do93
ephemeris (4)
116-119 I4 s Dur Duration of the event (5)
121-124 I4 s Dur2 ? Duration of the event calculated with Do93
ephemeris (5)
126-128 F3.1 --- Dist Apparent distance from the occulted or
eclipsed satellite to the center of Saturn
in saturnian radii (6)
130-133 F4.3 arcsec Impact Impact parameter (7)
135-138 F4.3 arcsec Impact2 Impact parameter calculated with Do93
ephemeris (7)
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Note (1): Nature of the event:
1O2 means that satellite 1 occults satellite 2,
3E4 means that satellite 3 eclipses satellite 4, etc.
Note (2): Type of eclipse as follows:
P = partial eclipse
A = annular eclipse
T = total eclipse
blank = an eclipse by the penumbra
Note (3): Flux drop:
0 = no event, but a small magnitude drop may be recorded due to
the uncertainties of the ephemerides
1 = total event
Note (4): Magnitude drop:
if 0, no event, but a small magnitude drop may be recorded due to the
uncertainties of the ephemerides; if very large, total event.
Note (5): No duration is indicated for grazing events. The eclipse inside
the penumbra is not taken into account in the duration.
Note (6): If this distance is less than 1, it means that the event occurs
in front of the planet Saturn. This is a nice observation -especially
the eclipses- with a good seeing, but without any scientific interest!
These events are only available from the web site.
Note (7): Apparent distance between the centers of the satellites for the
occultations and from the eclipsed satellite to the axis of the shadow
cone for the eclipses.
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Acknowledgements:
Jean-Eudes Arlot, jean-eudes.arlot(at)imcce.fr
(End) Patricia Vannier [CDS] 17-Apr-2008