C/1984 A1 (Bradfield 1)
| 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) |
| 2026-02-03 00:00 |
00:20:26.82 |
+29:21:07.7 |
HIP 1680 |
22.58 |
| 2026-02-03 12:00 |
00:20:28.47 |
+29:21:03.6 |
HIP 1680 |
22.53 |
| 2026-02-04 00:00 |
00:20:30.15 |
+29:20:59.6 |
HIP 1680 |
22.48 |
| 2026-02-04 12:00 |
00:20:31.84 |
+29:20:55.9 |
HIP 1680 |
22.43 |
| 2026-02-05 00:00 |
00:20:33.55 |
+29:20:52.3 |
HIP 1680 |
22.39 |
| 2026-02-05 12:00 |
00:20:35.27 |
+29:20:48.9 |
HIP 1680 |
22.34 |
| 2026-02-06 00:00 |
00:20:37.01 |
+29:20:45.8 |
HIP 1680 |
22.30 |
| 2026-02-06 12:00 |
00:20:38.77 |
+29:20:42.7 |
HIP 1680 |
22.27 |
| 2026-02-07 00:00 |
00:20:40.55 |
+29:20:39.9 |
HIP 1680 |
22.23 |
| 2026-02-07 12:00 |
00:20:42.34 |
+29:20:37.3 |
HIP 1680 |
22.20 |
| 2026-02-08 00:00 |
00:20:44.15 |
+29:20:34.8 |
HIP 1680 |
22.18 |
| 2026-02-08 12:00 |
00:20:45.97 |
+29:20:32.5 |
HIP 1680 |
22.15 |
| 2026-02-09 00:00 |
00:20:47.81 |
+29:20:30.5 |
HIP 1680 |
22.13 |
| 2026-02-09 12:00 |
00:20:49.67 |
+29:20:28.6 |
HIP 1680 |
22.11 |
| 2026-02-10 00:00 |
00:20:51.54 |
+29:20:26.9 |
HIP 1680 |
22.10 |
| 2026-02-10 12:00 |
00:20:53.43 |
+29:20:25.3 |
HIP 1680 |
22.09 |
| 2026-02-11 00:00 |
00:20:55.33 |
+29:20:24.0 |
HIP 1680 |
22.09 |
| 2026-02-11 12:00 |
00:20:57.25 |
+29:20:22.8 |
HIP 1680 |
22.09 |
| 2026-02-12 00:00 |
00:20:59.19 |
+29:20:21.9 |
HIP 1680 |
22.10 |
| 2026-02-12 12:00 |
00:21:01.14 |
+29:20:21.1 |
HIP 1680 |
22.11 |
| 2026-02-13 00:00 |
00:21:03.10 |
+29:20:20.5 |
HIP 1680 |
22.12 |
| 2026-02-13 12:00 |
00:21:05.08 |
+29:20:20.1 |
HIP 1680 |
22.14 |
| 2026-02-14 00:00 |
00:21:07.07 |
+29:20:19.8 |
HIP 1680 |
22.17 |
| 2026-02-14 12:00 |
00:21:09.08 |
+29:20:19.8 |
HIP 1680 |
22.20 |
| 2026-02-15 00:00 |
00:21:11.10 |
+29:20:20.0 |
HIP 1680 |
22.24 |
| 2026-02-15 12:00 |
00:21:13.14 |
+29:20:20.3 |
HIP 1799 |
22.17 |
| 2026-02-16 00:00 |
00:21:15.19 |
+29:20:20.8 |
HIP 1799 |
21.74 |
| 2026-02-16 12:00 |
00:21:17.26 |
+29:20:21.5 |
HIP 1799 |
21.31 |
| 2026-02-17 00:00 |
00:21:19.33 |
+29:20:22.4 |
HIP 1799 |
20.88 |
| 2026-02-17 12:00 |
00:21:21.43 |
+29:20:23.5 |
HIP 1799 |
20.44 |
| 2026-02-18 00:00 |
00:21:23.53 |
+29:20:24.8 |
HIP 1799 |
20.00 |
| 2026-02-18 12:00 |
00:21:25.65 |
+29:20:26.2 |
HIP 1799 |
19.56 |
| 2026-02-19 00:00 |
00:21:27.78 |
+29:20:27.8 |
HIP 1799 |
19.12 |
| 2026-02-19 12:00 |
00:21:29.93 |
+29:20:29.7 |
HIP 1799 |
18.67 |
| 2026-02-20 00:00 |
00:21:32.08 |
+29:20:31.7 |
HIP 1799 |
18.22 |
| 2026-02-20 12:00 |
00:21:34.25 |
+29:20:33.9 |
HIP 1799 |
17.77 |
| 2026-02-21 00:00 |
00:21:36.43 |
+29:20:36.2 |
HIP 1799 |
17.31 |
| 2026-02-21 12:00 |
00:21:38.63 |
+29:20:38.8 |
HIP 1799 |
16.86 |
| 2026-02-22 00:00 |
00:21:40.83 |
+29:20:41.5 |
HIP 1799 |
16.40 |
| 2026-02-22 12:00 |
00:21:43.05 |
+29:20:44.5 |
HIP 1799 |
15.94 |
| 2026-02-23 00:00 |
00:21:45.28 |
+29:20:47.6 |
HIP 1799 |
15.47 |
| 2026-02-23 12:00 |
00:21:47.52 |
+29:20:50.9 |
HIP 1799 |
15.01 |
| 2026-02-24 00:00 |
00:21:49.77 |
+29:20:54.3 |
HIP 1799 |
14.54 |