| 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) |
| 2026-03-26 00:00 |
22:03:26.55 |
+04:05:10.7 |
HIP 108901 |
18.43 |
| 2026-03-26 12:00 |
22:03:28.28 |
+04:05:24.6 |
HIP 108901 |
18.15 |
| 2026-03-27 00:00 |
22:03:29.99 |
+04:05:38.5 |
HIP 108901 |
17.88 |
| 2026-03-27 12:00 |
22:03:31.70 |
+04:05:52.3 |
HIP 108901 |
17.63 |
| 2026-03-28 00:00 |
22:03:33.39 |
+04:06:06.2 |
HIP 108901 |
17.38 |
| 2026-03-28 12:00 |
22:03:35.07 |
+04:06:20.1 |
HIP 108901 |
17.14 |
| 2026-03-29 00:00 |
22:03:36.74 |
+04:06:34.0 |
HIP 108901 |
16.91 |
| 2026-03-29 12:00 |
22:03:38.41 |
+04:06:47.9 |
HIP 108901 |
16.69 |
| 2026-03-30 00:00 |
22:03:40.05 |
+04:07:01.8 |
HIP 108901 |
16.48 |
| 2026-03-30 12:00 |
22:03:41.69 |
+04:07:15.7 |
HIP 108901 |
16.29 |
| 2026-03-31 00:00 |
22:03:43.32 |
+04:07:29.6 |
HIP 108901 |
16.10 |
| 2026-03-31 12:00 |
22:03:44.94 |
+04:07:43.5 |
HIP 108901 |
15.92 |
| 2026-04-01 00:00 |
22:03:46.54 |
+04:07:57.3 |
HIP 108901 |
15.76 |
| 2026-04-01 12:00 |
22:03:48.13 |
+04:08:11.2 |
HIP 108901 |
15.61 |
| 2026-04-02 00:00 |
22:03:49.71 |
+04:08:25.1 |
HIP 108901 |
15.47 |
| 2026-04-02 12:00 |
22:03:51.28 |
+04:08:39.0 |
HIP 108901 |
15.34 |
| 2026-04-03 00:00 |
22:03:52.84 |
+04:08:52.8 |
HIP 108901 |
15.22 |
| 2026-04-03 12:00 |
22:03:54.38 |
+04:09:06.7 |
HIP 108901 |
15.12 |
| 2026-04-04 00:00 |
22:03:55.92 |
+04:09:20.5 |
HIP 108901 |
15.02 |
| 2026-04-04 12:00 |
22:03:57.44 |
+04:09:34.4 |
HIP 108901 |
14.94 |
| 2026-04-05 00:00 |
22:03:58.94 |
+04:09:48.2 |
HIP 108901 |
14.87 |
| 2026-04-05 12:00 |
22:04:00.44 |
+04:10:02.0 |
HIP 108901 |
14.81 |
| 2026-04-06 00:00 |
22:04:01.92 |
+04:10:15.8 |
HIP 108901 |
14.76 |
| 2026-04-06 12:00 |
22:04:03.39 |
+04:10:29.6 |
HIP 108901 |
14.73 |
| 2026-04-07 00:00 |
22:04:04.85 |
+04:10:43.4 |
HIP 108901 |
14.70 |
| 2026-04-07 12:00 |
22:04:06.29 |
+04:10:57.1 |
HIP 108901 |
14.69 |
| 2026-04-08 00:00 |
22:04:07.73 |
+04:11:10.9 |
HIP 108901 |
14.69 |
| 2026-04-08 12:00 |
22:04:09.15 |
+04:11:24.6 |
HIP 108901 |
14.70 |
| 2026-04-09 00:00 |
22:04:10.55 |
+04:11:38.3 |
HIP 108901 |
14.72 |
| 2026-04-09 12:00 |
22:04:11.94 |
+04:11:52.0 |
HIP 108901 |
14.74 |
| 2026-04-10 00:00 |
22:04:13.32 |
+04:12:05.7 |
HIP 108901 |
14.78 |
| 2026-04-10 12:00 |
22:04:14.69 |
+04:12:19.3 |
HIP 108901 |
14.83 |
| 2026-04-11 00:00 |
22:04:16.04 |
+04:12:33.0 |
HIP 108901 |
14.89 |
| 2026-04-11 12:00 |
22:04:17.38 |
+04:12:46.6 |
HIP 108901 |
14.95 |
| 2026-04-12 00:00 |
22:04:18.70 |
+04:13:00.1 |
HIP 108901 |
15.03 |
| 2026-04-12 12:00 |
22:04:20.01 |
+04:13:13.7 |
HIP 108901 |
15.11 |
| 2026-04-13 00:00 |
22:04:21.31 |
+04:13:27.2 |
HIP 108901 |
15.20 |
| 2026-04-13 12:00 |
22:04:22.59 |
+04:13:40.7 |
HIP 108901 |
15.30 |
| 2026-04-14 00:00 |
22:04:23.86 |
+04:13:54.2 |
HIP 108901 |
15.40 |
| 2026-04-14 12:00 |
22:04:25.11 |
+04:14:07.6 |
HIP 108901 |
15.51 |
| 2026-04-15 00:00 |
22:04:26.35 |
+04:14:21.0 |
HIP 108901 |
15.63 |
| 2026-04-15 12:00 |
22:04:27.58 |
+04:14:34.4 |
HIP 108901 |
15.75 |
| 2026-04-16 00:00 |
22:04:28.79 |
+04:14:47.8 |
HIP 108901 |
15.88 |