Asteroid (2003 GY) Diameter: 280 - 640 m
Reason for SOHO offline, 2003 GY?
6/20/03 2:34:28 AM Pacific Daylight Time
Hi Kent,
Of course 2003 GY is even with 0.05 AU distance no danger for Earth, but
there might be something else:
Via the link "Generate High-Accuracy Ephemeris" of the Orbit Simulator
at neo.jpl.nasa.gov you can see that asteroid 2003 GY is reaching SOHO
C3 and even C2 field of view around August 13!
On the generated attached table, the column "S-O-T" is showing the
visible angle between Sun and 2003GY. When it gets below 17 it is in
the C3 field of view.
Of couse, normally, we wouldn't see that object with the C3 cam, as the
magnitude around 30 is way too dark (see other column). But who knows,
what the effects of that object inside the solar electromagnetic field
will show? Maybe they fear, that something unusual could happend and
"had that antenna problem" for that reason?
BTW, did you already linked to
http://www.jmccanneyscience.com/
------------------------------------------------------------------
Ephemeris Generator
Ephemeris Settings
Target Body: *Asteroid (2003 GY)*
Observer Location: *User Specified Location*
Coordinates: *0°00'00.0''E, 0°00'00.0''N*
From: *A.D. 2003-08-06 00:00 UT*
To: *A.D. 2003-08-20 00:00 *
Step: *1 day*
Format: *Calendar Date and Time*
Output Quantities: *1,9,23*
Ref. Frame, RA/Dec Format: *J2000, HMS*
Apparent Coordinates Model: *Airless*
------------------------------------------------------------------------
HORIZONS Generated Ephemeris
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Ephemeris / WWW_USER Fri Jun 20 02:24:18 2003 Pasadena, USA / Horizons
*******************************************************************************
Target body name: (2003 GY) {source: JPL#14}
Center body name: Earth (399) {source: DE-0406LE-0406}
Center-site name: (User Defined Site)
*******************************************************************************
Start time : A.D. 2003-Aug-06 00:00:00.0000 UT
Stop time : A.D. 2003-Aug-20 00:00:00.0000 UT
Step-size : 1440 minutes
*******************************************************************************
Center geodetic : 0.000000, 0.0000, -0.0030{E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.000000, 6378.1370, 0.0000{E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : High-precision EOP model {East-longitude +}
Center radii : 6378.1 x 6378.1 x 6356.8 km {Equator, meridian, pole}
Target pole/equ : No model available
Target radii : (unavailable)
Target primary : Sun {source: DE-0406LE-0406}
Interfering body: MOON (Req= 1737.400) km {source: DE-0406LE-0406}
Deflecting body : Sun, EARTH {source: DE-0406LE-0406}
Deflecting GMs : 1.3271E+11, 3.9860E+05 km^3/s^2
Small perturbers: Ceres, Pallas, Vesta {source: SB405-CPV-2}
Small body GMs : 6.32E+01, 1.43E+01, 1.78E+01 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
EOP file : eop.030617.p030908
EOP coverage : DATA-BASED 1962-JAN-20 TO 2003-JUN-17. PREDICTS-> 2003-SEP-07
Units conversion: 1 AU= 149597870.691 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO )
Table cut-offs 2: Solar Elongation ( 0.0,180.0=NO )
*******************************************************************************
Initial heliocentric osc. elements wrt ecliptic and mean equinox of J2000.0:
EPOCH= 2452745.5 ! 2003-Apr-16.00 (CT) Residual RMS= .61675
EC= .3177361904143214 QR= .942128639250863 TP= 2452845.210346037
OM= 322.1427156966601 W= 334.0384180612504 IN= 4.676710706250578
Asteroid physical parameters:
GM= n.a. RAD= n.a. ROTPER= n.a.
H= 20.041 G= .150 B-V= n.a.
ALBEDO= n.a. STYP= n.a.
*******************************************************************************
Date__(UT)__HR:MN R.A._(ICRF/J2000.0)_DEC APmag S-O-T /r
*****************************************************************
2003-Aug-06 00:00 m 10 19 16.68 -01 57 27.1 22.92 26.7509 /T
2003-Aug-07 00:00 m 10 14 17.42 -00 38 03.1 23.46 24.0785 /T
2003-Aug-08 00:00 m 10 08 44.27 +00 50 20.2 24.17 21.2073 /T
2003-Aug-09 00:00 m 10 02 33.33 +02 28 36.9 25.15 18.1198 /T
2003-Aug-10 00:00 m 09 55 40.20 +04 17 40.7 26.59 14.8020 /T
2003-Aug-11 00:00 m 09 48 00.01 +06 18 21.5 28.92 11.2518 /T
2003-Aug-12 00:00 m 09 39 27.35 +08 31 20.1 33.22 7.5139 /T
2003-Aug-13 00:00 m 09 29 56.33 +10 57 00.9 42.98 3.9288 /T
2003-Aug-14 00:00 m 09 19 20.66 +13 35 22.0 45.87 3.3777 /L
2003-Aug-15 00:00 m 09 07 33.84 +16 25 44.4 33.41 7.2893 /L
2003-Aug-16 00:00 m 08 54 29.48 +19 26 39.2 27.80 12.2371 /L
2003-Aug-17 00:00 m 08 40 01.81 +22 35 38.4 24.78 17.6057 /L
2003-Aug-18 00:00 m 08 24 06.51 +25 49 10.2 22.87 23.2591 /L
2003-Aug-19 00:00 m 08 06 41.65 +29 02 44.9 21.52 29.1091 /L
2003-Aug-20 00:00 m 07 47 48.93 +32 11 11.9 20.48 35.0689 /L
*******************************************************************************
Column meaning:
TIME
Prior to 1962, times are UT1. Dates thereafter are UTC. Any 'b' symbol in
the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D.
date. Calendar dates prior to 1582-Oct-15 are in the Julian calendar system.
Later calendar dates are in the Gregorian system.
The uniform Coordinate Time scale is used internally. Conversion between
CT and the selected non-uniform UT output scale has not been determined for
UTC times after the next July or January 1st. The last known leap-second
is used over any future interval.
NOTE: "n.a." in output means quantity "not available" at the print-time.
SOLAR PRESENCE
Time tag is followed by a blank, then a solar-presence symbol:
'*' Daylight (refracted solar upper-limb on or above apparent horizon)
'C' Civil twilight/dawn
'N' Nautical twilight/dawn
'A' Astronomical twilight/dawn
' ' Night OR geocentric ephemeris
LUNAR PRESENCE
The solar-presence symbol is immediately followed by a lunar-presence symbol:
'm' Refracted upper-limb of Moon on or above apparent horizon
' ' Refracted upper-limb of Moon below apparent horizon OR geocentric
ephemeris
R.A._(ICRF/J2000.0)_DEC =
J2000.0 astrometric right ascension and declination of target. Corrected
for light-time. Units: HMS (HH MM SS.ff) and DMS (DD MM SS.f)
APmag =
Asteroid's approximate apparent visual magnitude by following definition:
APmag = H + 5*log10(delta) + 5*log10(r) - 2.5*log10((1-G)*phi1 + G*phi2).
Units: none
S-O-T /r =
Sun-Observer-Target angle; target's apparent solar elongation seen from
observer location at print-time. If negative, the target center is behind
the Sun. Angular units: DEGREES.
The '/r' column is a Sun-relative code, output for observing sites
with defined rotation models only.
/T indicates target trails Sun (evening sky)
/L indicates target leads Sun (morning sky)
NOTE: The S-O-T solar elongation angle is the total separation in any
direction. It does not indicate the angle of Sun leading or trailing.
Computations by ...
Solar System Dynamics Group, Horizons On-Line Ephemeris System
4800 Oak Grove Drive, Jet Propulsion Laboratory
Pasadena, CA 91109 USA
Information: http://ssd.jpl.nasa.gov/
Connect : telnet://ssd.jpl.nasa.gov:6775 (via browser)
telnet ssd.jpl.nasa.gov 6775 (via command-line)
Author : Jon.Giorgini@jpl.nasa.gov
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------------------------------------------------------------------------
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Last modified: 2001 November 6 16:20