| Parameter |
Value |
| Designation |
C/1986 V1 (Sorrells) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1987-03-09T15:47:46.700160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
360 |
| NEO |
- |
| M1 |
5.500 |
| K1 |
13.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1987-02-24.0000000 |
| e |
0.99992595 |
| q (au) |
1.721158 |
| a (au) |
23244.336024 |
| i (deg) |
160.579825 |
| Ω (om, deg) |
74.802450 |
| ω (w, deg) |
70.233014 |
| M (ma, deg) |
359.999996 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.512 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.512 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
10.000 |
| 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 |
| 1986-11-02 |
1986-12-29 |
+9.0293 |
-2.778 |
| 1986-12-29 |
1987-02-28 |
-7.9512 |
+1.990 |
| 1987-04-11 |
1987-09-20 |
-0.2477 |
-0.077 |
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 |
13:06:11.65 |
-23:17:30.0 |
HIP 64095 |
31.95 |
| 2026-07-29 12:00 |
13:06:12.18 |
-23:17:25.7 |
HIP 64095 |
31.89 |
| 2026-07-30 00:00 |
13:06:12.71 |
-23:17:21.5 |
HIP 64095 |
31.83 |
| 2026-07-30 12:00 |
13:06:13.27 |
-23:17:17.4 |
HIP 64095 |
31.76 |
| 2026-07-31 00:00 |
13:06:13.83 |
-23:17:13.5 |
HIP 64095 |
31.69 |
| 2026-07-31 12:00 |
13:06:14.42 |
-23:17:09.6 |
HIP 64095 |
31.62 |
| 2026-08-01 00:00 |
13:06:15.01 |
-23:17:05.8 |
HIP 64095 |
31.54 |
| 2026-08-01 12:00 |
13:06:15.62 |
-23:17:02.1 |
HIP 64095 |
31.47 |
| 2026-08-02 00:00 |
13:06:16.25 |
-23:16:58.6 |
HIP 64095 |
31.38 |
| 2026-08-02 12:00 |
13:06:16.89 |
-23:16:55.1 |
HIP 64095 |
31.30 |
| 2026-08-03 00:00 |
13:06:17.54 |
-23:16:51.7 |
HIP 64095 |
31.21 |
| 2026-08-03 12:00 |
13:06:18.21 |
-23:16:48.5 |
HIP 64095 |
31.12 |
| 2026-08-04 00:00 |
13:06:18.89 |
-23:16:45.3 |
HIP 64095 |
31.03 |
| 2026-08-04 12:00 |
13:06:19.59 |
-23:16:42.3 |
HIP 64095 |
30.93 |
| 2026-08-05 00:00 |
13:06:20.30 |
-23:16:39.3 |
HIP 64095 |
30.83 |
| 2026-08-05 12:00 |
13:06:21.02 |
-23:16:36.5 |
HIP 64095 |
30.73 |
| 2026-08-06 00:00 |
13:06:21.76 |
-23:16:33.8 |
HIP 64095 |
30.62 |
| 2026-08-06 12:00 |
13:06:22.51 |
-23:16:31.1 |
HIP 64095 |
30.51 |
| 2026-08-07 00:00 |
13:06:23.28 |
-23:16:28.6 |
HIP 64095 |
30.40 |
| 2026-08-07 12:00 |
13:06:24.06 |
-23:16:26.2 |
HIP 64095 |
30.28 |
| 2026-08-08 00:00 |
13:06:24.85 |
-23:16:23.9 |
HIP 64095 |
30.17 |
| 2026-08-08 12:00 |
13:06:25.66 |
-23:16:21.7 |
HIP 64095 |
30.04 |
| 2026-08-09 00:00 |
13:06:26.48 |
-23:16:19.6 |
HIP 64095 |
29.92 |
| 2026-08-09 12:00 |
13:06:27.32 |
-23:16:17.6 |
HIP 64095 |
29.79 |
| 2026-08-10 00:00 |
13:06:28.17 |
-23:16:15.7 |
HIP 64095 |
29.66 |
| 2026-08-10 12:00 |
13:06:29.03 |
-23:16:13.9 |
HIP 64095 |
29.53 |
| 2026-08-11 00:00 |
13:06:29.90 |
-23:16:12.2 |
HIP 64095 |
29.40 |
| 2026-08-11 12:00 |
13:06:30.79 |
-23:16:10.7 |
HIP 64095 |
29.26 |
| 2026-08-12 00:00 |
13:06:31.69 |
-23:16:09.2 |
HIP 64095 |
29.12 |
| 2026-08-12 12:00 |
13:06:32.61 |
-23:16:07.9 |
HIP 64095 |
28.98 |
| 2026-08-13 00:00 |
13:06:33.54 |
-23:16:06.6 |
HIP 64095 |
28.83 |
| 2026-08-13 12:00 |
13:06:34.48 |
-23:16:05.5 |
HIP 64095 |
28.68 |
| 2026-08-14 00:00 |
13:06:35.43 |
-23:16:04.5 |
HIP 64095 |
28.53 |
| 2026-08-14 12:00 |
13:06:36.40 |
-23:16:03.5 |
HIP 64095 |
28.38 |
| 2026-08-15 00:00 |
13:06:37.38 |
-23:16:02.7 |
HIP 64095 |
28.22 |
| 2026-08-15 12:00 |
13:06:38.38 |
-23:16:02.0 |
HIP 64095 |
28.07 |
| 2026-08-16 00:00 |
13:06:39.38 |
-23:16:01.4 |
HIP 64095 |
27.91 |
| 2026-08-16 12:00 |
13:06:40.40 |
-23:16:00.9 |
HIP 64095 |
27.74 |
| 2026-08-17 00:00 |
13:06:41.43 |
-23:16:00.5 |
HIP 64095 |
27.58 |
| 2026-08-17 12:00 |
13:06:42.47 |
-23:16:00.3 |
HIP 64095 |
27.41 |
| 2026-08-18 00:00 |
13:06:43.53 |
-23:16:00.1 |
HIP 64095 |
27.24 |
| 2026-08-18 12:00 |
13:06:44.60 |
-23:16:00.0 |
HIP 64095 |
27.07 |
| 2026-08-19 00:00 |
13:06:45.68 |
-23:16:00.1 |
HIP 64095 |
26.90 |