| 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) |
| 2026-05-12 00:00 |
22:05:10.12 |
+04:25:13.3 |
HIP 108901 |
23.66 |
| 2026-05-12 12:00 |
22:05:10.47 |
+04:25:23.6 |
HIP 108901 |
23.76 |
| 2026-05-13 00:00 |
22:05:10.81 |
+04:25:33.9 |
HIP 108901 |
23.86 |
| 2026-05-13 12:00 |
22:05:11.13 |
+04:25:44.0 |
HIP 108901 |
23.95 |
| 2026-05-14 00:00 |
22:05:11.43 |
+04:25:54.1 |
HIP 108901 |
24.04 |
| 2026-05-14 12:00 |
22:05:11.72 |
+04:26:04.1 |
HIP 108901 |
24.13 |
| 2026-05-15 00:00 |
22:05:11.98 |
+04:26:14.0 |
HIP 108901 |
24.22 |
| 2026-05-15 12:00 |
22:05:12.23 |
+04:26:23.8 |
HIP 108901 |
24.30 |
| 2026-05-16 00:00 |
22:05:12.47 |
+04:26:33.5 |
HIP 108901 |
24.38 |
| 2026-05-16 12:00 |
22:05:12.68 |
+04:26:43.2 |
HIP 108901 |
24.45 |
| 2026-05-17 00:00 |
22:05:12.88 |
+04:26:52.7 |
HIP 108901 |
24.52 |
| 2026-05-17 12:00 |
22:05:13.06 |
+04:27:02.2 |
HIP 108901 |
24.59 |
| 2026-05-18 00:00 |
22:05:13.22 |
+04:27:11.6 |
HIP 108901 |
24.65 |
| 2026-05-18 12:00 |
22:05:13.37 |
+04:27:20.9 |
HIP 108901 |
24.71 |
| 2026-05-19 00:00 |
22:05:13.50 |
+04:27:30.1 |
HIP 108901 |
24.77 |
| 2026-05-19 12:00 |
22:05:13.61 |
+04:27:39.2 |
HIP 108901 |
24.82 |
| 2026-05-20 00:00 |
22:05:13.70 |
+04:27:48.2 |
HIP 108901 |
24.87 |
| 2026-05-20 12:00 |
22:05:13.77 |
+04:27:57.2 |
HIP 108901 |
24.91 |
| 2026-05-21 00:00 |
22:05:13.83 |
+04:28:06.0 |
HIP 108901 |
24.95 |
| 2026-05-21 12:00 |
22:05:13.87 |
+04:28:14.8 |
HIP 108901 |
24.99 |
| 2026-05-22 00:00 |
22:05:13.89 |
+04:28:23.4 |
HIP 108901 |
25.02 |
| 2026-05-22 12:00 |
22:05:13.90 |
+04:28:32.0 |
HIP 108901 |
25.05 |
| 2026-05-23 00:00 |
22:05:13.88 |
+04:28:40.5 |
HIP 109078 |
24.95 |
| 2026-05-23 12:00 |
22:05:13.85 |
+04:28:48.8 |
HIP 109078 |
24.82 |
| 2026-05-24 00:00 |
22:05:13.81 |
+04:28:57.1 |
HIP 109078 |
24.70 |
| 2026-05-24 12:00 |
22:05:13.74 |
+04:29:05.3 |
HIP 109078 |
24.58 |
| 2026-05-25 00:00 |
22:05:13.66 |
+04:29:13.4 |
HIP 109078 |
24.46 |
| 2026-05-25 12:00 |
22:05:13.56 |
+04:29:21.4 |
HIP 109078 |
24.35 |
| 2026-05-26 00:00 |
22:05:13.44 |
+04:29:29.2 |
HIP 109078 |
24.24 |
| 2026-05-26 12:00 |
22:05:13.30 |
+04:29:37.0 |
HIP 109078 |
24.13 |
| 2026-05-27 00:00 |
22:05:13.15 |
+04:29:44.7 |
HIP 109078 |
24.03 |
| 2026-05-27 12:00 |
22:05:12.98 |
+04:29:52.3 |
HIP 109078 |
23.93 |
| 2026-05-28 00:00 |
22:05:12.79 |
+04:29:59.8 |
HIP 109078 |
23.83 |
| 2026-05-28 12:00 |
22:05:12.59 |
+04:30:07.2 |
HIP 109078 |
23.74 |
| 2026-05-29 00:00 |
22:05:12.37 |
+04:30:14.5 |
HIP 109078 |
23.65 |
| 2026-05-29 12:00 |
22:05:12.13 |
+04:30:21.7 |
HIP 109078 |
23.56 |
| 2026-05-30 00:00 |
22:05:11.87 |
+04:30:28.8 |
HIP 109078 |
23.48 |
| 2026-05-30 12:00 |
22:05:11.60 |
+04:30:35.8 |
HIP 109078 |
23.40 |
| 2026-05-31 00:00 |
22:05:11.31 |
+04:30:42.6 |
HIP 109078 |
23.33 |
| 2026-05-31 12:00 |
22:05:11.00 |
+04:30:49.4 |
HIP 109078 |
23.26 |
| 2026-06-01 00:00 |
22:05:10.67 |
+04:30:56.1 |
HIP 109078 |
23.19 |
| 2026-06-01 12:00 |
22:05:10.33 |
+04:31:02.7 |
HIP 109078 |
23.13 |
| 2026-06-02 00:00 |
22:05:09.97 |
+04:31:09.1 |
HIP 109078 |
23.07 |