Haumea.20111207 Occultation December 07, 2011

(last updated 2011 08 09)

OBSERVER NOTES

 

Across the globe pictured above, the three solid lines correspond to the northern limit, centerline, and southern limit of Haumea's shadow. The northern and southern limits correspond to a radius of 668.39 km. The upper and lower dashed lines indicate 3-sigma errors. The shaded area represents where the sun is more than 12 degrees below the horizon.
Table 1: Prediction Details
Haumea Geocentric Mid-time (yyyy month dd hh:mm:ss)

2011 December 07 10:45:57± 00:01:141 UT
Haumea Minimum Geocentric Separation 0.0521± 0.05421 arcsec
Position Angle (Pluto relative to the star; measured north through east) –6.78 degrees
Geocentric Velocity 23.72 km/sec
Occultation Star USNO-B R magnitude 17.022

1One standard deviation of random error.
2The UCAC bandpass (579-642nm) is between V and R.


Table 2: Reference Star Position
Reference star position:
(USNOB, at epoch of event)		 RA (h:m:s; J2000) Dec (d:m:s; J2000) Notes
Haumea.20111207 Catalog 13 52 17.4740± 0.062 +17 42 30.480± 0.083
Haumea.20111207 Measured3 13 52 17.4671± 0.0289 +17 42 30.320± 0.020
From 21 Lowell 42-inch and SMARTS 0.9m Telescope frames. See note 4.
Table 3: Projected KBO Offsets from Reference Ephemeris at the Time of the Event
Body RA (arcsec) Dec (arcsec)  
Haumea

–0.1426± 0.0214

 –0.058± 0.020 See Notes 5 and 6

3Measured position corresponds to RA offset of –0.1024 and Dec. offset of –0.160.

4All "offsets" are defined 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.

4Data analyzed using UCAC2 reference network. A weighted average of the data from the two telescopes was used to calculate the RA and DEC. The errors given are 1 standard deviation.

5The reference positions for Haumea are those given by JPL Horizon's ephemeris (Haumea source file: JPL36; Earth center source file: DE405).

6Data from the USNO 61-inch, SMARTS 0.9m, and Lowell 42-inch telescopes over the span of 3 years were reduced with respect to stars in the UCAC2 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 Haumea: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) sinusoidal terms with the Earth's orbital 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)
Dominion Astrophysical Obs.
-123 25 05
48 31 13
0.23
3161 N.
23.79
Lick
–121 38 12
37 20 36
1.29
2385 N.
23.78
Magdalena Ridge Obs.
–107 11 20
33 59 06
3.22
1717 N.
23.69
Palomar
–116 51 54
33 21 24
1.70
1945 N.
23.75
Pine Mountain Obs.
-120 56 22
43 47 31
1.98
2818 N.
23.77
Pomona
–117 42 35
34 05 51
0.36
2027 N.
23.75
San Pedo Martir
–115 27 49
31 02 39
2.83
1715 N.
23.75
Table Mountain Obs.
–117 40 50
34 22 55
2.29
2052 N.
23.76
University of Central Florida
–81 22 32
28 32 10
0.0
434 N.
23.52
USNO
–111 44 24
35 11 00
2.31
1948 N.
23.72
Wallace
–71 29 06
42 36 36
0.11
1460 N.
23.50
Williams
–73 12 06
42 42 42
0.22
1510 N.
23.51
WIRO
–105 58 36
41 05 54
2.94
2246 N.
23.69
Geocenter
----------
---------
center of Earth
1940 S.
23.74

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

7"Distance" refers to the closest approach distance of the "Site" to the center of Haumea's shadow in the shadow plane. The errors on all closest approach distances are ±2019 km (one standard deviation). "S." means the site is south of the center of Haumea's shadow. "N." means the site is north of the center of Haumea's shadow.

Table 5: Haumea.20111207 Occultation Predictions for Individual Sites

Site
Haumea Immersion (UT)9
UT Mid-Time
Haumea Altitude
Solar Altitude9

Haumea Emersion (UT)9
Dominion Astrophysical Obs.
-----------
10:43:27
10
-----------
-----------
Lick
-----------
10:42:44
8
-----------
-----------
Magdalena Ridge Obs.
-----------
10:42:38
19
-----------
-----------
Palomar
-----------
10:42:34
15
-----------
-----------
Pine Mountain Obs.
-----------
10:43:06
10
-----------
-----------
Pomona
-----------
10:42:36
15
-----------
-----------
San Pedro Martir
-----------
10:42:27
11
-----------
-----------
Table Mountain Obs.
-----------
10:42:34
10
-----------
-----------
University of Central Florida
10:42:40
10:43:02
40
–18
10:43:24
USNO
-----------
10:42:37
15
-----------
-----------
Wallace
-----------
10:43:59
46
–14
-----------
Williams
-----------
10:43:58
45
–15
-----------
WIRO
-----------
10:43:02
21
-----------
-----------
Geocenter
-----------
10:45:57
-----------
-----------
-----------

9The errors on all times are ±1:14 (1 minute and 14 seconds; one standard deviation). The solar altitude is given for locations where it is relevant (solar altitude greater than -18°). No entry in the immersion and emersion columns indicates that the occultation is not predicted to be visible at that site.

 

Last updated by Carlos Zuluaga (czuluaga@mit.edu) 2011-09-01 09:45

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

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