| Parameter |
Value |
| Designation |
C/1984 A1 (Bradfield 1) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1983-12-27T19:07:03.864000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
33 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1984-02-25.0000000 |
| e |
0.95231517 |
| q (au) |
1.357490 |
| a (au) |
28.467973 |
| i (deg) |
51.800566 |
| Ω (om, deg) |
356.858343 |
| ω (w, deg) |
219.164863 |
| M (ma, deg) |
0.384163 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.897 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.897 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
00:28:03.32 |
+29:58:35.5 |
HIP 2102 |
22.40 |
| 2026-05-12 12:00 |
00:28:05.23 |
+29:58:57.3 |
HIP 2102 |
22.52 |
| 2026-05-13 00:00 |
00:28:07.13 |
+29:59:19.1 |
HIP 2102 |
22.65 |
| 2026-05-13 12:00 |
00:28:09.02 |
+29:59:41.0 |
HIP 2326 |
22.55 |
| 2026-05-14 00:00 |
00:28:10.89 |
+30:00:02.9 |
HIP 2326 |
22.02 |
| 2026-05-14 12:00 |
00:28:12.74 |
+30:00:24.8 |
HIP 2326 |
21.50 |
| 2026-05-15 00:00 |
00:28:14.58 |
+30:00:46.7 |
HIP 2326 |
20.98 |
| 2026-05-15 12:00 |
00:28:16.41 |
+30:01:08.6 |
HIP 2326 |
20.47 |
| 2026-05-16 00:00 |
00:28:18.22 |
+30:01:30.6 |
HIP 2326 |
19.96 |
| 2026-05-16 12:00 |
00:28:20.01 |
+30:01:52.6 |
HIP 2326 |
19.45 |
| 2026-05-17 00:00 |
00:28:21.79 |
+30:02:14.6 |
HIP 2326 |
18.95 |
| 2026-05-17 12:00 |
00:28:23.55 |
+30:02:36.6 |
HIP 2326 |
18.46 |
| 2026-05-18 00:00 |
00:28:25.30 |
+30:02:58.6 |
HIP 2326 |
17.97 |
| 2026-05-18 12:00 |
00:28:27.03 |
+30:03:20.6 |
HIP 2326 |
17.48 |
| 2026-05-19 00:00 |
00:28:28.74 |
+30:03:42.7 |
HIP 2326 |
17.00 |
| 2026-05-19 12:00 |
00:28:30.44 |
+30:04:04.7 |
HIP 2326 |
16.53 |
| 2026-05-20 00:00 |
00:28:32.12 |
+30:04:26.8 |
HIP 2326 |
16.06 |
| 2026-05-20 12:00 |
00:28:33.78 |
+30:04:48.9 |
HIP 2326 |
15.60 |
| 2026-05-21 00:00 |
00:28:35.43 |
+30:05:10.9 |
HIP 2326 |
15.14 |
| 2026-05-21 12:00 |
00:28:37.06 |
+30:05:33.0 |
HIP 2326 |
14.69 |
| 2026-05-22 00:00 |
00:28:38.67 |
+30:05:55.1 |
HIP 2326 |
14.26 |
| 2026-05-22 12:00 |
00:28:40.27 |
+30:06:17.2 |
HIP 2326 |
13.82 |
| 2026-05-23 00:00 |
00:28:41.85 |
+30:06:39.2 |
HIP 2326 |
13.40 |
| 2026-05-23 12:00 |
00:28:43.41 |
+30:07:01.3 |
HIP 2326 |
12.99 |
| 2026-05-24 00:00 |
00:28:44.96 |
+30:07:23.4 |
HIP 2326 |
12.58 |
| 2026-05-24 12:00 |
00:28:46.49 |
+30:07:45.5 |
HIP 2326 |
12.19 |
| 2026-05-25 00:00 |
00:28:48.00 |
+30:08:07.5 |
HIP 2326 |
11.81 |
| 2026-05-25 12:00 |
00:28:49.49 |
+30:08:29.6 |
HIP 2326 |
11.44 |
| 2026-05-26 00:00 |
00:28:50.96 |
+30:08:51.6 |
HIP 2326 |
11.09 |
| 2026-05-26 12:00 |
00:28:52.42 |
+30:09:13.6 |
HIP 2326 |
10.74 |
| 2026-05-27 00:00 |
00:28:53.86 |
+30:09:35.7 |
HIP 2326 |
10.42 |
| 2026-05-27 12:00 |
00:28:55.28 |
+30:09:57.7 |
HIP 2326 |
10.11 |
| 2026-05-28 00:00 |
00:28:56.69 |
+30:10:19.7 |
HIP 2326 |
9.82 |
| 2026-05-28 12:00 |
00:28:58.07 |
+30:10:41.6 |
HIP 2326 |
9.54 |
| 2026-05-29 00:00 |
00:28:59.44 |
+30:11:03.6 |
HIP 2326 |
9.29 |
| 2026-05-29 12:00 |
00:29:00.79 |
+30:11:25.5 |
HIP 2326 |
9.05 |
| 2026-05-30 00:00 |
00:29:02.12 |
+30:11:47.4 |
HIP 2326 |
8.84 |
| 2026-05-30 12:00 |
00:29:03.43 |
+30:12:09.3 |
HIP 2326 |
8.66 |
| 2026-05-31 00:00 |
00:29:04.72 |
+30:12:31.2 |
HIP 2326 |
8.50 |
| 2026-05-31 12:00 |
00:29:06.00 |
+30:12:53.1 |
HIP 2326 |
8.36 |
| 2026-06-01 00:00 |
00:29:07.25 |
+30:13:14.9 |
HIP 2326 |
8.25 |
| 2026-06-01 12:00 |
00:29:08.49 |
+30:13:36.7 |
HIP 2326 |
8.17 |
| 2026-06-02 00:00 |
00:29:09.71 |
+30:13:58.5 |
HIP 2326 |
8.11 |