Triton.20221006

October 06, 2022

Finder Charts

Observing Information

Prediction Last Updated: January 22, 2022

 

Across the globe pictured, the three solid black lines correspond to the northern limit, centerline, and southern limit of the Triton’s shadow. The Northern and Southern limits correspond to a radius of 1353 km. The dashed lines indicate 3-sigma errors. The shaded area on the globe represents where the sun is more than 0 degrees below the horizon. The shadow paths on the globe are an approximation at the geocentric close approach time; they disregard the Earth rotation during the event.



Table 1: Prediction Details
Triton Geocentric Mid-time (hh:mm:ss)

October 06, 2022 14:39:44 ± 00:00:27. UT1

Prediction pred2.0_v1.0
Triton apparent magnitude 13.4
Occultation Star Gaia DR2 G magnitude 11.553864
Occultation Star Gaia DR2 rp magnitude 11.094841
Occultation Star Gaia DR2 bp magnitude 11.869446
Triton Minimum Geocentric Separation 0.2098 ± 0.0100 arcsec1
Position Angle (Triton relative to the star; measured north through east) -15.88

1One standard deviation of random error




Table 2: Reference Star Position
Reference star position:
(Gaia DR3)
RA (h:m:s; J2000) Dec (d:m:s; J2000) Notes
Triton.20221006 (Catalog; epoch of occ) 23:36:52.4514 ± 0.0006 -03:50:09.7954 ± 0.0004
Triton.20221006 (Measured) - -

Potential Star Duplicity:

Unknown




Table 3: Projected KBO Offsets from Reference Ephemeris at the Time of the Event
Body RA (arcsec) Dec (arcsec)  
Triton

0.0000 ± 0.0100

0.0000 ± 0.0100 See Notes 5 and 6; Includes Triton Center of Light to Center of Body correction

2Measured position corresponds to RA offset of 0. and Dec. offset of 0.

3All "offsets" are degined in the ("corrected"–"reference") or ("observed"–"calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction.

4The reference positions for Triton are those given by JPL Horizon's ephemeris (Triton source file: nep081xl ; Earth center source file: nep081xl)

5Data from various telescope were reduced with respect to the Gaia DR2 catalog. A model was developed to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris. All residuals obtained from the different telescopes were consistent with the model. The model includes the first-order effects of errors in the orbital elements of the object: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) potential sinusoidal terms with companion's period. The model was propagated to obtain the predicted position and error of the KBO at the time of the occultation. The errors listed for the KBO are 1 standard deviation.




Table 4: Site Information
Site
East Longitude
Latitude

Site Altitude6

(km)

Distance7

(km)

Velocity

(km/s)

Bangkok
100 30 06
13 45 22
0.
2057 S
23.10
Beijing
116 24 26
39 54 15
0.
126 S
23.02
Blagoveschensk
127 28 58
50 19 04
0.26
381 N
22.96
Chiang Mai
98 57 30
18 51 09
0.
1522 S
23.09
Hong Kong
114 10 09
22 19 09
0.
1586 S
23.10
Mumbai
72 52 39
19 04 33
0.
977 S
22.99
New Delhi
77 12 32
28 36 50
0.
216 S
22.99
Osaka
135 30 08
34 41 37
0.
1019 S
23.03
Sanglokh Observatory
69 13 04
38 15 38
0.
609 N
22.93
Shanghai
121 28 25
31 13 49
0.
964 S
23.06
Taipei City
121 33 55
25 01 58
0.
1531 S
23.09
Thai National Telescope
98 28 55
18 34 55
2.547
1536 S
23.09
Tokyo
139 46 08
35 40 49
0.
1038 S
23.01
Tunka
103 04 01
51 48 36
0.680
921 N
22.96
Yunnan Observatory
102 46 48
25 01 48
0.
1042 S
23.08
Geocentric
..........
..........
-6378.14
4046 S
22.68

6Altitude of each observatory is measured in kilometers above sea level.

7"Distance" refers to the closest approach of the "Site" to the center of Triton's shadow in the shadow plane. The errors on all closest approach distances are ±210 km (one standard deviation). "S." means the site is south of the center of Triton's shadow. "N." means the site is north of the center of Triton's shadow.




Table 5: Triton Occultation Predictions for Individual Sites
Site
Immersion (UT)8
UT Mid-Time
KBO Altitude

Solar Altitude8

Emersion (UT)8

Bangkok
........
14:40:44
65
-53
........
Beijing
14:37:55
14:39:02
46
-50
14:40:09
Blagoveschensk
14:37:22
14:38:18
35
-44
14:39:15
Chiang Mai
........
14:40:42
60
-51
........
Hong Kong
........
14:39:33
63
-62
........
Mumbai
14:41:27
14:42:19
40
-26
14:43:11
New Delhi
14:40:35
14:41:42
39
-29
14:42:48
Osaka
14:37:05
14:37:56
49
-61
14:38:46
Sanglokh Observatory
14:40:43
14:41:36
28
-21
14:42:29
Shanghai
14:38:00
14:38:52
55
-60
14:39:44
Taipei City
14:38:49
14:38:58
61
-65
14:39:07
Thai National Telescope
........
14:40:45
60
-50
........
Tokyo
14:36:51
14:37:40
46
-60
14:38:30
Tunka
14:38:45
14:39:28
33
-35
14:40:12
Yunnan Observatory
14:39:39
14:40:16
57
-52
14:40:54
Geocentric
........
14:39:49
........

8The errors on all times are ± 0:27. (27 seconds; one standard deviation). The solar altitude is given for locations where it is relevant (solar altitude greater than -18 deg). No entry in the immersion and emersion columns indicates that the occultation is not predicted to be visible at that site.




Webpage generated by C. A. Zuluaga (czuluaga@mit.edu) on July 5, 2022

Please direct all inquiries to PAL (planetary-astronomy@mit.edu)