| Parameter |
Value |
| Designation |
C/1991 Y1 (Zanotta-Brewington) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1992-01-31T23:47:40.372800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:41Z |
| Obs used |
266 |
| NEO |
- |
| M1 |
10.200 |
| K1 |
14.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1992-01-10.0000000 |
| e |
1.00005670 |
| q (au) |
0.643969 |
| a (au) |
-11357.972781 |
| i (deg) |
50.028225 |
| Ω (om, deg) |
254.908258 |
| ω (w, deg) |
197.872524 |
| M (ma, deg) |
-0.000018 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.204 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.204 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.800 |
| 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 |
| 1991-12-23 |
1992-01-31 |
+0.0509 |
+0.039 |
| 1992-02-01 |
1992-05-02 |
+12.8239 |
+2.103 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
17:08:16.90 |
-18:19:30.8 |
HIP 83850 |
7.01 |
| 2026-09-20 12:00 |
17:08:17.29 |
-18:19:33.2 |
HIP 83850 |
7.00 |
| 2026-09-21 00:00 |
17:08:17.70 |
-18:19:35.7 |
HIP 83850 |
6.99 |
| 2026-09-21 12:00 |
17:08:18.12 |
-18:19:38.1 |
HIP 83850 |
6.98 |
| 2026-09-22 00:00 |
17:08:18.57 |
-18:19:40.6 |
HIP 83850 |
6.97 |
| 2026-09-22 12:00 |
17:08:19.03 |
-18:19:43.1 |
HIP 83850 |
6.97 |
| 2026-09-23 00:00 |
17:08:19.51 |
-18:19:45.6 |
HIP 83850 |
6.97 |
| 2026-09-23 12:00 |
17:08:20.00 |
-18:19:48.1 |
HIP 83850 |
6.98 |
| 2026-09-24 00:00 |
17:08:20.51 |
-18:19:50.6 |
HIP 83850 |
6.99 |
| 2026-09-24 12:00 |
17:08:21.05 |
-18:19:53.1 |
HIP 83850 |
7.00 |
| 2026-09-25 00:00 |
17:08:21.59 |
-18:19:55.7 |
HIP 83850 |
7.02 |
| 2026-09-25 12:00 |
17:08:22.16 |
-18:19:58.3 |
HIP 83850 |
7.04 |
| 2026-09-26 00:00 |
17:08:22.74 |
-18:20:00.9 |
HIP 83850 |
7.06 |
| 2026-09-26 12:00 |
17:08:23.34 |
-18:20:03.5 |
HIP 83850 |
7.09 |
| 2026-09-27 00:00 |
17:08:23.96 |
-18:20:06.1 |
HIP 83850 |
7.13 |
| 2026-09-27 12:00 |
17:08:24.59 |
-18:20:08.8 |
HIP 83850 |
7.17 |
| 2026-09-28 00:00 |
17:08:25.24 |
-18:20:11.4 |
HIP 83850 |
7.21 |
| 2026-09-28 12:00 |
17:08:25.91 |
-18:20:14.1 |
HIP 83850 |
7.26 |
| 2026-09-29 00:00 |
17:08:26.59 |
-18:20:16.8 |
HIP 83850 |
7.31 |
| 2026-09-29 12:00 |
17:08:27.29 |
-18:20:19.5 |
HIP 83850 |
7.38 |
| 2026-09-30 00:00 |
17:08:28.01 |
-18:20:22.2 |
HIP 83850 |
7.44 |
| 2026-09-30 12:00 |
17:08:28.75 |
-18:20:24.9 |
HIP 83850 |
7.52 |
| 2026-10-01 00:00 |
17:08:29.50 |
-18:20:27.7 |
HIP 83850 |
7.59 |
| 2026-10-01 12:00 |
17:08:30.27 |
-18:20:30.4 |
HIP 83850 |
7.68 |
| 2026-10-02 00:00 |
17:08:31.05 |
-18:20:33.2 |
HIP 83850 |
7.77 |
| 2026-10-02 12:00 |
17:08:31.85 |
-18:20:36.0 |
HIP 83850 |
7.87 |
| 2026-10-03 00:00 |
17:08:32.67 |
-18:20:38.8 |
HIP 83850 |
7.97 |
| 2026-10-03 12:00 |
17:08:33.51 |
-18:20:41.6 |
HIP 83850 |
8.08 |
| 2026-10-04 00:00 |
17:08:34.36 |
-18:20:44.4 |
HIP 83850 |
8.20 |
| 2026-10-04 12:00 |
17:08:35.22 |
-18:20:47.3 |
HIP 83850 |
8.32 |
| 2026-10-05 00:00 |
17:08:36.11 |
-18:20:50.1 |
HIP 83850 |
8.45 |
| 2026-10-05 12:00 |
17:08:37.01 |
-18:20:53.0 |
HIP 83850 |
8.58 |
| 2026-10-06 00:00 |
17:08:37.93 |
-18:20:55.8 |
HIP 83850 |
8.72 |
| 2026-10-06 12:00 |
17:08:38.86 |
-18:20:58.7 |
HIP 83850 |
8.87 |
| 2026-10-07 00:00 |
17:08:39.81 |
-18:21:01.6 |
HIP 83850 |
9.02 |
| 2026-10-07 12:00 |
17:08:40.78 |
-18:21:04.5 |
HIP 83850 |
9.18 |
| 2026-10-08 00:00 |
17:08:41.76 |
-18:21:07.4 |
HIP 83850 |
9.35 |
| 2026-10-08 12:00 |
17:08:42.75 |
-18:21:10.4 |
HIP 83850 |
9.52 |
| 2026-10-09 00:00 |
17:08:43.77 |
-18:21:13.3 |
HIP 83850 |
9.70 |
| 2026-10-09 12:00 |
17:08:44.80 |
-18:21:16.3 |
HIP 83850 |
9.89 |
| 2026-10-10 00:00 |
17:08:45.84 |
-18:21:19.2 |
HIP 83850 |
10.08 |
| 2026-10-10 12:00 |
17:08:46.90 |
-18:21:22.2 |
HIP 83850 |
10.27 |
| 2026-10-11 00:00 |
17:08:47.98 |
-18:21:25.1 |
HIP 83850 |
10.48 |