| Parameter |
Value |
| Designation |
C/1993 Y1 (McNaught-Russell) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1994-03-31T02:18:06.736320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:47Z |
| Obs used |
377 |
| NEO |
- |
| M1 |
12.300 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1994-04-28.0000000 |
| e |
0.99355692 |
| q (au) |
0.867635 |
| a (au) |
134.661517 |
| i (deg) |
51.586469 |
| Ω (om, deg) |
166.359073 |
| ω (w, deg) |
353.467558 |
| M (ma, deg) |
0.017600 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.244 + 4.880\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.244 |
| n |
4.880 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
1.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 1993-12-17 |
1994-03-02 |
+18.4445 |
-0.750 |
| 1994-03-02 |
1994-03-31 |
-10.7206 |
-0.342 |
| 1994-03-31 |
1994-06-09 |
-1.1734 |
-0.051 |
| 1994-06-09 |
1994-10-02 |
+5.2847 |
-0.850 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
22:02:50.67 |
+04:30:40.3 |
HIP 108769 |
12.25 |
| 2026-07-29 12:00 |
22:02:48.79 |
+04:30:33.2 |
HIP 108769 |
11.77 |
| 2026-07-30 00:00 |
22:02:46.90 |
+04:30:26.0 |
HIP 108769 |
11.28 |
| 2026-07-30 12:00 |
22:02:45.01 |
+04:30:18.7 |
HIP 108769 |
10.80 |
| 2026-07-31 00:00 |
22:02:43.10 |
+04:30:11.3 |
HIP 108769 |
10.31 |
| 2026-07-31 12:00 |
22:02:41.20 |
+04:30:03.8 |
HIP 108769 |
9.82 |
| 2026-08-01 00:00 |
22:02:39.28 |
+04:29:56.2 |
HIP 108769 |
9.32 |
| 2026-08-01 12:00 |
22:02:37.36 |
+04:29:48.4 |
HIP 108769 |
8.83 |
| 2026-08-02 00:00 |
22:02:35.43 |
+04:29:40.6 |
HIP 108769 |
8.33 |
| 2026-08-02 12:00 |
22:02:33.50 |
+04:29:32.6 |
HIP 108769 |
7.83 |
| 2026-08-03 00:00 |
22:02:31.56 |
+04:29:24.6 |
HIP 108769 |
7.33 |
| 2026-08-03 12:00 |
22:02:29.61 |
+04:29:16.4 |
HIP 108769 |
6.83 |
| 2026-08-04 00:00 |
22:02:27.66 |
+04:29:08.2 |
HIP 108769 |
6.33 |
| 2026-08-04 12:00 |
22:02:25.70 |
+04:28:59.8 |
HIP 108769 |
5.83 |
| 2026-08-05 00:00 |
22:02:23.74 |
+04:28:51.3 |
HIP 108769 |
5.32 |
| 2026-08-05 12:00 |
22:02:21.78 |
+04:28:42.8 |
HIP 108769 |
4.82 |
| 2026-08-06 00:00 |
22:02:19.80 |
+04:28:34.1 |
HIP 108769 |
4.32 |
| 2026-08-06 12:00 |
22:02:17.83 |
+04:28:25.3 |
HIP 108769 |
3.81 |
| 2026-08-07 00:00 |
22:02:15.85 |
+04:28:16.4 |
HIP 108769 |
3.31 |
| 2026-08-07 12:00 |
22:02:13.86 |
+04:28:07.4 |
HIP 108769 |
2.81 |
| 2026-08-08 00:00 |
22:02:11.87 |
+04:27:58.3 |
HIP 108769 |
2.33 |
| 2026-08-08 12:00 |
22:02:09.88 |
+04:27:49.1 |
HIP 108769 |
1.85 |
| 2026-08-09 00:00 |
22:02:07.88 |
+04:27:39.8 |
HIP 108769 |
1.41 |
| 2026-08-09 12:00 |
22:02:05.87 |
+04:27:30.4 |
HIP 108769 |
1.05 |
| 2026-08-10 00:00 |
22:02:03.87 |
+04:27:20.9 |
HIP 108769 |
0.86 |
| 2026-08-10 12:00 |
22:02:01.86 |
+04:27:11.4 |
HIP 108769 |
0.98 |
| 2026-08-11 00:00 |
22:01:59.85 |
+04:27:01.7 |
HIP 108769 |
1.31 |
| 2026-08-11 12:00 |
22:01:57.83 |
+04:26:51.9 |
HIP 108769 |
1.75 |
| 2026-08-12 00:00 |
22:01:55.81 |
+04:26:42.0 |
HIP 108769 |
2.22 |
| 2026-08-12 12:00 |
22:01:53.79 |
+04:26:32.0 |
HIP 108769 |
2.72 |
| 2026-08-13 00:00 |
22:01:51.76 |
+04:26:21.9 |
HIP 108769 |
3.23 |
| 2026-08-13 12:00 |
22:01:49.73 |
+04:26:11.8 |
HIP 108769 |
3.75 |
| 2026-08-14 00:00 |
22:01:47.70 |
+04:26:01.5 |
HIP 108769 |
4.27 |
| 2026-08-14 12:00 |
22:01:45.67 |
+04:25:51.2 |
HIP 108769 |
4.80 |
| 2026-08-15 00:00 |
22:01:43.63 |
+04:25:40.7 |
HIP 108769 |
5.33 |
| 2026-08-15 12:00 |
22:01:41.60 |
+04:25:30.2 |
HIP 108769 |
5.86 |
| 2026-08-16 00:00 |
22:01:39.56 |
+04:25:19.5 |
HIP 108769 |
6.39 |
| 2026-08-16 12:00 |
22:01:37.52 |
+04:25:08.8 |
HIP 108769 |
6.93 |
| 2026-08-17 00:00 |
22:01:35.48 |
+04:24:58.0 |
HIP 108769 |
7.46 |
| 2026-08-17 12:00 |
22:01:33.43 |
+04:24:47.1 |
HIP 108769 |
8.00 |
| 2026-08-18 00:00 |
22:01:31.39 |
+04:24:36.1 |
HIP 108769 |
8.54 |
| 2026-08-18 12:00 |
22:01:29.34 |
+04:24:25.1 |
HIP 108769 |
9.08 |
| 2026-08-19 00:00 |
22:01:27.30 |
+04:24:13.9 |
HIP 108769 |
9.62 |