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May 13: Important Update to the information below::
Dr J.Lecacheux has advised of a small shift in the path of the LINUS occultation as follows. These corrections should be applied to the LINUS central line data given further down this page:
Taking the solution issued by Steve Preston on May 7th as a reference, the new solution
that Jan Manek sent us this evening (private communication) is shifted by 35.4 km SOUTHward,
and 6.7 seconds LATE.
In consequence, if we consider a fictitious centerline midway between those of S.Preston and
J.Manek as the most probable center of the uncertainty domain, the whole occultation scenario
(main body and Linus) is expected now 35.4 /2 = ~18 km more south than previously.
Please note the following special predictions of closest approach of the satellite (Linus)
to Rockhampton (QL) [E150 34' S23 23'] (nominal solutions without uncertainties):
1/ Satellite center :
according to S.Preston : 7.2 km South
according to J.Manek : 43.0 km South
2/ Northern limb of the satellite (assuming D= 38 km )
according to S.Preston : 11.8 km North
according to J.Manek : 24.0 km South
Probable uncertainty of the above distances : ± 90 km
(at 95 % confidence level)
3/ Time :
according to S.Preston : 12:18:04.5 UTC ± 7.5 sec.
according to J.Manek : 12:18:11.0 UTC ± 9 sec.
The text of IAU Circular 8338 pertaining to the May 14 (and June 5) Linus occultations is as follows:
Circular No. 8338
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
(22) KALLIOPE I (LINUS)
J. Berthier, P. Descamps, and D. Hestroffer, Institut de
Mecanique Celeste et de Calcul des Ephemerides, Observatoire de
Paris (OP); J. Lecacheux, Laboratoire d'Etudes Spatiales et
d'Instrumentation en Astrophysique, OP; and F. Marchis, University
of California at Berkeley, report on the probable ground track of
two stellar occultations of Hipparcos/Tycho stars by Linus, the
satellite of (22) Kalliope (cf. IAUC 7703, 8177). On May 14.5083
and June 5.8812 UTC, the stars TYC 6816-00087 (R.A. = 17h17m.0,
Decl. = -25o08', equinox 2000.0) and 6814-00458 (R.A. = 16h57m.3,
Decl. = -26o04') will be occulted for 15.4 s by (22) Kalliope with
drops of 0.7 and 0.9 magnitude, respectively (Goffin 2003,
ftp://ftp.ster.kuleuven.ac.be/dist/vvs/asteroids; Preston 2004,
http://www.asteroidoccultation.com/). According to the orbit of
Linus, as computed by Marchis et al. (2003, Icarus 165, 112) and
improved with observations gathered during the past three years
with several adaptive-optics systems (Lick 3-m, Palomar 5-m, VLT
8-m, and Keck 10-m telescopes), in addition to observations
published by Margot and Brown (2003, Science 300, 1939), the two
stellar occultations will occur when Linus is located, relative to
the primary, at Delta(R.A.) = -0".14 and Delta(Decl.) = +0".53 on
May 14.5083, and at Delta(R.A.) = -0".47 and Delta(Decl.) = -0".24
on June 5.8812. The occultations will be visible along a 40-km-
wide shadow located, respectively, about 8 degrees north and about
5 degrees south of the primary occultation track, respectively,
which itself crosses southern Australia and the south Pacific on
May 14 and the northern Mediterranean Sea countries and Russia on
June 5. The occultations by Linus are expected to last < 3.2 s.
Shadow path, details, and updates can be obtained at website URL
http://www.imcce.fr/observateur/target/targobs.php?target=Kalliope.
Preamble:
On May 14 an occultation by asteroid 22 Kalliope will be visible from northern NSW, central regions of Australia, and Exmouth in WA. The accuracy of this track is very high, although the change of magnitide at occultation of 0.7 will make the event diffocult for visual observers.
While observation of the occultation by Kalliope is important, what is more important is observation of an occultation by Kalliope's confirmed satellite Linus. This event is generating considerable interest amongst professional researchers. The satellite has been followed since its discovery by the world's largest telescopes using adaptive optics, with a view to improve it's orbital parameters and to derive the physical characteristics of Kalliope and the Kalliope/Linus system. Observation of an occultation by Linus would provide an additional data point of much greater accuracy than has previously been obtained, leading to significant downstream scientific results.
Occultation by Linus - Details:
Observation of an occultation by Kalliope's moonlet Linus is important because:
Click here for letters we have received from professional astronomers in Europe underlying the importance of this event.
The following plot shows the wide path of the occultation by Kalliope itself across mid and northern NSW, together with the path of the occultation by the ~38 km diameter satellite across mid-Queensland.
The plot below shows the detailed track (centre line only) of the satellite's shadow across Queensland and its proximity to Rockhampton.
The location of the center line of the occultation by Linus is as follows. (Data kindly provided by Dr J.Lecacheux):
Geographic coordinates
--------------------------------------------
UTC East South star
on 2004 Longitude Latitude altitude
MAY 14 deg. min. deg. min. deg.
--------------------------------------------
12:18:00 151 20 23 33 44
06 150 19 23 25 43
12 149 18 23 17 42
18 148 15 23 07 41
24 147 11 22 57 40
30 146 06 22 47 39
36 145 00 22 36 38
42 143 53 22 23 37
48 142 44 22 10 36
12:18:54 141 34 21 57 35
12:19:00 140 22 21 42 34
06 139 08 21 26 33
12 137 52 21 08 31
18 136 35 20 50 30
24 135 14 20 30 29
30 133 51 20 08 28
36 132 24 19 45 26
42 130 54 19 20 25
48 129 18 18 52 23
12:19:53.5 127 45 18 23 22
.... .... .... ....
12:20:13.6 121 03 16 06 15
Dr Lecacheux notes that the track uncertainty is a bit larger (perhaps by 15-20%) for the satellite than in Steve Preston's update for Kalliope alone (see below). From the 12.065 km/s expected speed of the shadow across the earth, the maximum duration of any occultation by Linus should be ~3.5 seconds.
Orientation of Kalliope and position of Linus at the time of occultation::
The following diagram shows the expected orientation of Kalliope at 12:12 UT on the night of its occultation. This synthetic image of Kalliope has been computed from the preliminary 3D-model derived by the IMCCE (Institut de Mechanique Celeste et de Calcul Des Ephemerides) from resolved VLT pictures of the asteroid. Note that Kalliope should rotate by ~9 degrees around its spin axis between the nominal time of the Kalliope image below (12:12 UT) and its arrival at the east-australian coast at 12:18 UT.
Dr Lecacheux notes that as the motion vector will be toward p.a.= 253.4 degrees, the real path width could be ~195 km -a bit larger than assumed by Steve Preston, and the maximum chord duration near 14 seconds. Real chord measurements should permit them to test and to improve the tentative 3D-model.
He further notes that light curve measurements of Kalliope before and after the occultation will also be very useful.
The following diagram shows the position of Linus relative to its parent at close to the time of its occultation on May 14:
Links for further information::
You are strongly urged to visit the following link which provides much greater detail as the scientific value of the Kalliope/Linus occultations together with extensive information about large-telescope observations to date:
http://www.imcce.fr/observateur/target/targobs.php?target=Kalliope#k
PRESTON UPDATE: 2004 MAY 07, 16:50 UT
THE UPDATED PATH FOR KALLIOPE ONLY
(Note: The duration given in the line below is the interval during which the occultation shadow sweeps across the Earth - please see the minute markers on the map to determine the approximate the time for your location)
On 2004 May 14 UT, the 181 km diameter asteroid (22) Kalliope will occult a 11.4 mag star in the constellation Ophiuchus for observers along a path across Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.7 mag to 11.2 mag (the magnitude of the asteroid) for at most 15.4 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC.
Additional details of this and other events are available at Steve Preston's website at http://www.asteroidoccultation.com/
EVENT DETAILS SUMMARY :Important Note regarding Accuracy:
The uncertainty interval in path widths given above (and shown as a 1-sigma uncertainty ellipse on the plot) refers to RMS deviation and is applied as a +/- range. In other words, a path uncertainty of 1.0 path widths means that the actual center of the asteroid's shadow path should fall within plus or minus 1 path width of the plotted path center. However path errors larger than 1 sigma have been observed so observers should be alert for primary occultations within plus or minus 3 sigma of the updated path.
Further, almost all asteroidal satellites discovered so far have been found within 10 diameters of the asteroid (since this distance is deep enough within the gravitational well to be stable over long timescales). Therefore, if monitoring for secondary events, observing out to about 10 path-widths either side of the predicted track remains worthwhile.
We therefore recommend that you monitor for events if your observing location is up to +/- 10 path-widths from the predicted track. If not monitoring for occultations by secondary bodies you should observe from locations within 3 sigma of the nominal path.
In terms of time, the predictions are now usually accurate to about +/- 0.3 minute so you should be most attentive during the predicted minute of the event. However if intending to catch a potential satellite occultation you should start observing at least 10 times the predicted central duration before the predicted closest approach time for your location, and continue for a similar period afterwards.
Centre Star Star Sun Path Limits Error Limits
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Latitude Latitude Latitude Latitude
110 0 0 -20 29 9 12 20 29 7 114 -30 -19 35 14 -21 23 6 -19 10 26 -21 47 56
111 0 0 -20 54 41 12 20 28 8 114 -31 -20 0 54 -21 48 30 -19 36 10 -22 13 16
112 0 0 -21 19 46 12 20 26 9 114 -32 -20 26 7 -22 13 26 -20 1 26 -22 38 9
113 0 0 -21 44 24 12 20 24 10 113 -33 -20 50 53 -22 37 56 -20 26 16 -23 2 35
114 0 0 -22 8 34 12 20 23 11 113 -34 -21 15 12 -23 1 59 -20 50 39 -23 26 34
115 0 0 -22 32 18 12 20 21 12 112 -35 -21 39 4 -23 25 35 -21 14 34 -23 50 6
116 0 0 -22 55 35 12 20 19 13 112 -36 -22 2 28 -23 48 43 -21 38 3 -24 13 10
117 0 0 -23 18 24 12 20 16 14 112 -37 -22 25 25 -24 11 24 -22 1 3 -24 35 48
118 0 0 -23 40 45 12 20 14 15 111 -38 -22 47 54 -24 33 37 -22 23 36 -24 57 57
119 0 0 -24 2 39 12 20 12 16 111 -39 -23 9 56 -24 55 23 -22 45 42 -25 19 39
120 0 0 -24 24 5 12 20 9 17 110 -40 -23 31 30 -25 16 41 -23 7 19 -25 40 54
121 0 0 -24 45 3 12 20 6 18 110 -41 -23 52 36 -25 37 32 -23 28 29 -26 1 41
122 0 0 -25 5 34 12 20 3 19 110 -42 -24 13 15 -25 57 55 -23 49 11 -26 22 0
123 0 0 -25 25 36 12 20 0 20 109 -42 -24 33 25 -26 17 50 -24 9 25 -26 41 52
124 0 0 -25 45 11 12 19 57 21 109 -43 -24 53 8 -26 37 17 -24 29 11 -27 1 15
125 0 0 -26 4 18 12 19 54 22 108 -44 -25 12 22 -26 56 16 -24 48 29 -27 20 12
126 0 0 -26 22 58 12 19 51 23 108 -45 -25 31 9 -27 14 48 -25 7 19 -27 38 40
127 0 0 -26 41 9 12 19 47 24 107 -46 -25 49 28 -27 32 53 -25 25 41 -27 56 41
128 0 0 -26 58 53 12 19 43 25 107 -47 -26 7 19 -27 50 29 -25 43 36 -28 14 14
129 0 0 -27 16 9 12 19 40 26 107 -48 -26 24 42 -28 7 38 -26 1 2 -28 31 20
130 0 0 -27 32 58 12 19 36 26 106 -49 -26 41 37 -28 24 20 -26 18 1 -28 47 58
131 0 0 -27 49 18 12 19 32 27 106 -49 -26 58 5 -28 40 34 -26 34 32 -29 4 9
132 0 0 -28 5 12 12 19 28 28 105 -50 -27 14 5 -28 56 20 -26 50 35 -29 19 53
133 0 0 -28 20 38 12 19 24 29 105 -51 -27 29 37 -29 11 40 -27 6 10 -29 35 9
134 0 0 -28 35 36 12 19 20 30 104 -52 -27 44 42 -29 26 32 -27 21 18 -29 49 58
135 0 0 -28 50 7 12 19 15 31 104 -53 -27 59 20 -29 40 57 -27 35 58 -30 4 20
136 0 0 -29 4 11 12 19 11 32 103 -54 -28 13 30 -29 54 55 -27 50 11 -30 18 15
137 0 0 -29 17 48 12 19 6 33 103 -54 -28 27 13 -30 8 25 -28 3 57 -30 31 43
138 0 0 -29 30 58 12 19 2 34 102 -55 -28 40 28 -30 21 29 -28 17 15 -30 44 45
139 0 0 -29 43 41 12 18 57 35 102 -56 -28 53 17 -30 34 7 -28 30 6 -30 57 19
140 0 0 -29 55 57 12 18 52 35 101 -57 -29 5 38 -30 46 17 -28 42 30 -31 9 27
141 0 0 -30 7 46 12 18 47 36 101 -58 -29 17 32 -30 58 1 -28 54 27 -31 21 9
142 0 0 -30 19 8 12 18 43 37 100 -58 -29 29 0 -31 9 18 -29 5 57 -31 32 24
143 0 0 -30 30 4 12 18 38 38 100 -59 -29 40 1 -31 20 9 -29 17 0 -31 43 12
144 0 0 -30 40 34 12 18 32 39 99 -60 -29 50 35 -31 30 34 -29 27 36 -31 53 35
145 0 0 -30 50 37 12 18 27 40 99 -61 -30 0 43 -31 40 32 -29 37 46 -32 3 31
146 0 0 -31 0 13 12 18 22 41 98 -61 -30 10 24 -31 50 5 -29 47 29 -32 13 1
147 0 0 -31 9 24 12 18 17 41 98 -62 -30 19 38 -31 59 11 -29 56 46 -32 22 6
148 0 0 -31 18 8 12 18 11 42 97 -63 -30 28 27 -32 7 51 -30 5 36 -32 30 44
149 0 0 -31 26 26 12 18 6 43 96 -64 -30 36 49 -32 16 6 -30 14 0 -32 38 57
150 0 0 -31 34 19 12 18 0 44 96 -64 -30 44 45 -32 23 54 -30 21 58 -32 46 44
151 0 0 -31 41 45 12 17 55 45 95 -65 -30 52 15 -32 31 17 -30 29 29 -32 54 5
152 0 0 -31 48 46 12 17 49 46 95 -66 -30 59 19 -32 38 15 -30 36 35 -33 1 1
153 0 0 -31 55 21 12 17 43 46 94 -66 -31 5 57 -32 44 47 -30 43 14 -33 7 32
154 0 0 -32 1 31 12 17 38 47 94 -67 -31 12 10 -32 50 53 -30 49 28 -33 13 37
155 0 0 -32 7 15 12 17 32 48 93 -68 -31 17 56 -32 56 35 -30 55 16 -33 19 17
156 0 0 -32 12 33 12 17 26 49 93 -68 -31 23 17 -33 1 51 -31 0 38 -33 24 32
157 0 0 -32 17 26 12 17 20 50 92 -69 -31 28 13 -33 6 41 -31 5 34 -33 29 21
158 0 0 -32 21 54 12 17 14 51 91 -70 -31 32 42 -33 11 7 -31 10 5 -33 33 46
159 0 0 -32 25 56 12 17 8 51 91 -70 -31 36 47 -33 15 7 -31 14 10 -33 37 46
160 0 0 -32 29 33 12 17 2 52 90 -71 -31 40 26 -33 18 43 -31 17 50 -33 41 20
161 0 0 -32 32 45 12 16 55 53 90 -71 -31 43 39 -33 21 53 -31 21 4 -33 44 30
162 0 0 -32 35 32 12 16 49 54 89 -72 -31 46 27 -33 24 39 -31 23 53 -33 47 15
163 0 0 -32 37 54 12 16 43 55 88 -72 -31 48 50 -33 27 0 -31 26 17 -33 49 35
164 0 0 -32 39 51 12 16 36 56 88 -73 -31 50 48 -33 28 56 -31 28 15 -33 51 31
165 0 0 -32 41 23 12 16 30 56 87 -73 -31 52 21 -33 30 27 -31 29 48 -33 53 2
166 0 0 -32 42 30 12 16 24 57 87 -74 -31 53 28 -33 31 33 -31 30 55 -33 54 8
167 0 0 -32 43 11 12 16 17 58 86 -74 -31 54 10 -33 32 15 -31 31 38 -33 54 49
168 0 0 -32 43 28 12 16 10 59 85 -75 -31 54 27 -33 32 31 -31 31 55 -33 55 6
169 0 0 -32 43 21 12 16 4 60 85 -75 -31 54 19 -33 32 24 -31 31 47 -33 54 58
170 0 0 -32 42 48 12 15 57 60 84 -75 -31 53 46 -33 31 51 -31 31 14 -33 54 26
171 0 0 -32 41 50 12 15 50 61 83 -76 -31 52 48 -33 30 54 -31 30 15 -33 53 29
172 0 0 -32 40 28 12 15 43 62 83 -76 -31 51 25 -33 29 32 -31 28 52 -33 52 8
173 0 0 -32 38 40 12 15 36 63 82 -76 -31 49 37 -33 27 46 -31 27 3 -33 50 22
174 0 0 -32 36 28 12 15 29 64 81 -76 -31 47 23 -33 25 35 -31 24 49 -33 48 11
175 0 0 -32 33 51 12 15 22 64 81 -76 -31 44 45 -33 22 59 -31 22 11 -33 45 36
176 0 0 -32 30 49 12 15 15 65 80 -76 -31 41 42 -33 19 59 -31 19 7 -33 42 36
177 0 0 -32 27 22 12 15 8 66 79 -76 -31 38 13 -33 16 33 -31 15 37 -33 39 12
178 0 0 -32 23 31 12 15 1 67 78 -76 -31 34 20 -33 12 44 -31 11 43 -33 35 23
179 0 0 -32 19 14 12 14 54 68 78 -76 -31 30 1 -33 8 29 -31 7 24 -33 31 9
180 0 0 -32 14 33 12 14 47 69 77 -76 -31 25 18 -33 3 50 -31 2 39 -33 26 31
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