J/AJ/164/240 Cassini observations for 20 saturnian satellites (Jacobson+, 2022)
Ephemerides of the Irregular Saturnian Satellites from Earth-based Astrometry
and Cassini Imaging.
Jacobson R.A.,Brozovic M.,Mastrodemos N.,Riedel J.E.,Sheppard S.S.
<Astron. J., 164, 240 (2022)>
=2022AJ....164..240J 2022AJ....164..240J
ADC_Keywords: Solar system; Minor planets; Positional data; Optical
Keywords: Saturnian satellites
Abstract:
We report a new determination of the orbits of the irregular Saturnian
satellites. We fit their numerically integrated orbits to a data set
containing Earth-based observations and imaging data from the Cassini
spacecraft. We include the statistics of the observation residuals,
the satellites' orbital elements, and projected accuracies of the
satellites' positions. We also provide astrometric positions derived
from the Cassini imaging. Two of the satellites are considered lost
because they have not been observed for more than one epoch and have
indeterminate uncertainties in their positions. Three of the
satellites appear to be in a Kozai resonance, with one being the first
irregular satellite of any planet found to be in a 270° rather
than 90° resonance.
Description:
The imaging observations from Cassini cover 2008-2017. The raw
imaging data can be obtained from the Planetary Data System
Cartography and Imaging Node 3.
Using the background stars to define the Cassini camera pointing, we
determined 597 astrometric positions of the following satellites:
Ymir, Paaliaq, Tarvos, Ijiraq, Suttungr, Kiviuq, Mundilfari, Albiorix,
Skathi, Erriapus, Siarnaq, Thrymr, Bebhionn, Bergelmir, Bestla, Hati,
Kari, Loge, Skoll, and Tarqeq.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 123 597 *Cassini imaging observations
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Note on table2.dat : This table contains 597 astrometric positions
obtained from the ISS NAC instrument on board of Cassini spacecraft of
the irregular Saturnian satellites Ymir, Paaliaq, Tarvos, Ijiraq,
Suttungr, Kiviuq, Mundilfari, Albiorix, Skathi, Erriapus, Siarnaq,
Thrymr, Bebhionn, Bergelmir, Bestla, Hati, Kari, Loge, Skoll, and
Tarqeq for the time span 2008-2017.
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See also:
J/A+A/580/A76 : Positions of satellites of giant planets (Gomes-Junior+, 2015)
J/AJ/153/147 : The orbits of Jupiter's irregular satellites (Brozovic+, 2017)
J/AJ/163/241 : Residual stats. Uranus & Neptune satellites (Brozovic+, 2022)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Image Image name
13- 14 I2 d Obs.D UTC Observation date, day
16- 18 A3 "month" Obs.M UTC Observation date, month
20- 23 I4 yr Obs.Y [2008/2017] UTC Observation date, year
25- 26 I2 h Obs.h UTC Observation date, hour
28- 29 I2 min Obs.m UTC Observation date, minute
31- 34 F4.1 s Obs.s UTC Observation date, second
36- 43 A8 --- Sat Observed satellite
45- 51 F7.3 pix posS [132/710] Satellite sample position on image
53- 59 F7.3 pix posL [157/609] Satellite's line position on image
61- 65 F5.3 pix e_posS [0.2/5] Uncertainty on Sample
67- 71 F5.3 pix e_posL [0.2/4] Uncertainty on Line
73- 79 F7.3 deg CamRAdeg [14.5/356] Camera pointing Right Ascension
(ICRF)
81- 87 F7.3 deg CamDEdeg [-84.4/78.4] Camera pointing Declination
(ICRF)
89- 95 F7.3 deg Twist [1.42/359] Camera's twist angle
97-103 F7.3 deg RAdeg [14.5/356] Satellite's Right Ascension (ICRF)
105-109 F5.3 deg e_RAdeg [0.3/9] Uncertainty in RAdeg
111-117 F7.3 deg DEdeg [-84.4/78.4] Satellite's Declination (ICRF)
119-123 F5.3 deg e_DEdeg [0.3/8] Uncertainty in DEdeg
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 27-Jan-2023