| Parameter |
Value |
| Designation |
C/1989 A3 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-12-05T05:51:56.764800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
23 |
| NEO |
Yes |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1989-01-25.0000000 |
| e |
0.97809250 |
| q (au) |
0.420517 |
| a (au) |
19.195134 |
| i (deg) |
83.059274 |
| Ω (om, deg) |
28.437814 |
| ω (w, deg) |
194.769984 |
| M (ma, deg) |
0.594842 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.535 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.535 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
0.987 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
01:37:28.20 |
+24:53:42.6 |
HIP 7564 |
16.40 |
| 2026-07-29 12:00 |
01:37:27.63 |
+24:53:52.6 |
HIP 7564 |
16.23 |
| 2026-07-30 00:00 |
01:37:27.03 |
+24:54:02.4 |
HIP 7564 |
16.06 |
| 2026-07-30 12:00 |
01:37:26.41 |
+24:54:12.1 |
HIP 7564 |
15.90 |
| 2026-07-31 00:00 |
01:37:25.75 |
+24:54:21.6 |
HIP 7564 |
15.74 |
| 2026-07-31 12:00 |
01:37:25.08 |
+24:54:31.0 |
HIP 7564 |
15.58 |
| 2026-08-01 00:00 |
01:37:24.37 |
+24:54:40.3 |
HIP 7564 |
15.43 |
| 2026-08-01 12:00 |
01:37:23.64 |
+24:54:49.4 |
HIP 7564 |
15.28 |
| 2026-08-02 00:00 |
01:37:22.88 |
+24:54:58.3 |
HIP 7564 |
15.13 |
| 2026-08-02 12:00 |
01:37:22.10 |
+24:55:07.1 |
HIP 7564 |
15.00 |
| 2026-08-03 00:00 |
01:37:21.29 |
+24:55:15.7 |
HIP 7564 |
14.86 |
| 2026-08-03 12:00 |
01:37:20.45 |
+24:55:24.2 |
HIP 7564 |
14.73 |
| 2026-08-04 00:00 |
01:37:19.59 |
+24:55:32.5 |
HIP 7564 |
14.61 |
| 2026-08-04 12:00 |
01:37:18.70 |
+24:55:40.7 |
HIP 7564 |
14.49 |
| 2026-08-05 00:00 |
01:37:17.78 |
+24:55:48.7 |
HIP 7564 |
14.38 |
| 2026-08-05 12:00 |
01:37:16.83 |
+24:55:56.5 |
HIP 7564 |
14.28 |
| 2026-08-06 00:00 |
01:37:15.86 |
+24:56:04.2 |
HIP 7564 |
14.19 |
| 2026-08-06 12:00 |
01:37:14.87 |
+24:56:11.7 |
HIP 7564 |
14.10 |
| 2026-08-07 00:00 |
01:37:13.84 |
+24:56:19.1 |
HIP 7564 |
14.02 |
| 2026-08-07 12:00 |
01:37:12.79 |
+24:56:26.3 |
HIP 7564 |
13.95 |
| 2026-08-08 00:00 |
01:37:11.72 |
+24:56:33.4 |
HIP 7564 |
13.88 |
| 2026-08-08 12:00 |
01:37:10.61 |
+24:56:40.2 |
HIP 7564 |
13.83 |
| 2026-08-09 00:00 |
01:37:09.49 |
+24:56:47.0 |
HIP 7564 |
13.78 |
| 2026-08-09 12:00 |
01:37:08.33 |
+24:56:53.5 |
HIP 7564 |
13.75 |
| 2026-08-10 00:00 |
01:37:07.15 |
+24:57:00.0 |
HIP 7564 |
13.72 |
| 2026-08-10 12:00 |
01:37:05.94 |
+24:57:06.1 |
HIP 7564 |
13.71 |
| 2026-08-11 00:00 |
01:37:04.71 |
+24:57:12.2 |
HIP 7564 |
13.71 |
| 2026-08-11 12:00 |
01:37:03.45 |
+24:57:18.1 |
HIP 7564 |
13.71 |
| 2026-08-12 00:00 |
01:37:02.16 |
+24:57:23.8 |
HIP 7564 |
13.73 |
| 2026-08-12 12:00 |
01:37:00.85 |
+24:57:29.4 |
HIP 7564 |
13.76 |
| 2026-08-13 00:00 |
01:36:59.51 |
+24:57:34.7 |
HIP 7564 |
13.81 |
| 2026-08-13 12:00 |
01:36:58.15 |
+24:57:40.0 |
HIP 7564 |
13.86 |
| 2026-08-14 00:00 |
01:36:56.76 |
+24:57:45.0 |
HIP 7564 |
13.93 |
| 2026-08-14 12:00 |
01:36:55.35 |
+24:57:49.9 |
HIP 7564 |
14.01 |
| 2026-08-15 00:00 |
01:36:53.91 |
+24:57:54.6 |
HIP 7564 |
14.10 |
| 2026-08-15 12:00 |
01:36:52.44 |
+24:57:59.2 |
HIP 7564 |
14.21 |
| 2026-08-16 00:00 |
01:36:50.95 |
+24:58:03.5 |
HIP 7564 |
14.32 |
| 2026-08-16 12:00 |
01:36:49.44 |
+24:58:07.7 |
HIP 7564 |
14.45 |
| 2026-08-17 00:00 |
01:36:47.89 |
+24:58:11.7 |
HIP 7564 |
14.60 |
| 2026-08-17 12:00 |
01:36:46.33 |
+24:58:15.6 |
HIP 7564 |
14.75 |
| 2026-08-18 00:00 |
01:36:44.74 |
+24:58:19.3 |
HIP 7564 |
14.92 |
| 2026-08-18 12:00 |
01:36:43.12 |
+24:58:22.8 |
HIP 7564 |
15.11 |
| 2026-08-19 00:00 |
01:36:41.48 |
+24:58:26.1 |
HIP 7564 |
15.30 |