| Parameter |
Value |
| Designation |
C/1972 E1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1972-03-27T16:49:37.511040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:19Z |
| Obs used |
85 |
| NEO |
- |
| M1 |
9.000 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1972-04-24.0000000 |
| e |
0.99814080 |
| q (au) |
0.927218 |
| a (au) |
498.718434 |
| i (deg) |
123.692688 |
| Ω (om, deg) |
160.299080 |
| ω (w, deg) |
257.698891 |
| M (ma, deg) |
0.002416 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.513 + 3.707\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.513 |
| n |
3.707 |
| gf |
0.999 |
| gb |
-0.500 |
| k |
0.978 |
| δ90 |
2.272 |
| 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 |
08:38:19.54 |
+69:31:13.4 |
HIP 42273 |
12.30 |
| 2026-07-29 12:00 |
08:38:23.57 |
+69:31:09.9 |
HIP 42273 |
12.53 |
| 2026-07-30 00:00 |
08:38:27.61 |
+69:31:06.5 |
HIP 42273 |
12.76 |
| 2026-07-30 12:00 |
08:38:31.64 |
+69:31:03.3 |
HIP 42273 |
12.99 |
| 2026-07-31 00:00 |
08:38:35.68 |
+69:31:00.3 |
HIP 42273 |
13.23 |
| 2026-07-31 12:00 |
08:38:39.71 |
+69:30:57.3 |
HIP 42273 |
13.47 |
| 2026-08-01 00:00 |
08:38:43.75 |
+69:30:54.6 |
HIP 42273 |
13.72 |
| 2026-08-01 12:00 |
08:38:47.78 |
+69:30:51.9 |
HIP 42273 |
13.96 |
| 2026-08-02 00:00 |
08:38:51.82 |
+69:30:49.4 |
HIP 42273 |
14.21 |
| 2026-08-02 12:00 |
08:38:55.85 |
+69:30:47.0 |
HIP 42273 |
14.47 |
| 2026-08-03 00:00 |
08:38:59.88 |
+69:30:44.8 |
HIP 42273 |
14.72 |
| 2026-08-03 12:00 |
08:39:03.91 |
+69:30:42.7 |
HIP 42652 |
14.69 |
| 2026-08-04 00:00 |
08:39:07.93 |
+69:30:40.8 |
HIP 42652 |
14.36 |
| 2026-08-04 12:00 |
08:39:11.96 |
+69:30:39.0 |
HIP 42652 |
14.03 |
| 2026-08-05 00:00 |
08:39:15.98 |
+69:30:37.3 |
HIP 42652 |
13.70 |
| 2026-08-05 12:00 |
08:39:20.00 |
+69:30:35.8 |
HIP 42652 |
13.38 |
| 2026-08-06 00:00 |
08:39:24.01 |
+69:30:34.4 |
HIP 42652 |
13.06 |
| 2026-08-06 12:00 |
08:39:28.02 |
+69:30:33.2 |
HIP 42652 |
12.74 |
| 2026-08-07 00:00 |
08:39:32.03 |
+69:30:32.1 |
HIP 42652 |
12.42 |
| 2026-08-07 12:00 |
08:39:36.04 |
+69:30:31.2 |
HIP 42652 |
12.11 |
| 2026-08-08 00:00 |
08:39:40.04 |
+69:30:30.4 |
HIP 42652 |
11.81 |
| 2026-08-08 12:00 |
08:39:44.03 |
+69:30:29.7 |
HIP 42652 |
11.50 |
| 2026-08-09 00:00 |
08:39:48.03 |
+69:30:29.2 |
HIP 42652 |
11.21 |
| 2026-08-09 12:00 |
08:39:52.01 |
+69:30:28.8 |
HIP 42652 |
10.91 |
| 2026-08-10 00:00 |
08:39:55.99 |
+69:30:28.6 |
HIP 42652 |
10.62 |
| 2026-08-10 12:00 |
08:39:59.97 |
+69:30:28.5 |
HIP 42652 |
10.34 |
| 2026-08-11 00:00 |
08:40:03.94 |
+69:30:28.6 |
HIP 42652 |
10.06 |
| 2026-08-11 12:00 |
08:40:07.90 |
+69:30:28.8 |
HIP 42652 |
9.79 |
| 2026-08-12 00:00 |
08:40:11.86 |
+69:30:29.1 |
HIP 42652 |
9.53 |
| 2026-08-12 12:00 |
08:40:15.81 |
+69:30:29.6 |
HIP 42652 |
9.28 |
| 2026-08-13 00:00 |
08:40:19.76 |
+69:30:30.3 |
HIP 42652 |
9.03 |
| 2026-08-13 12:00 |
08:40:23.70 |
+69:30:31.0 |
HIP 42652 |
8.79 |
| 2026-08-14 00:00 |
08:40:27.62 |
+69:30:32.0 |
HIP 42652 |
8.56 |
| 2026-08-14 12:00 |
08:40:31.55 |
+69:30:33.1 |
HIP 42652 |
8.34 |
| 2026-08-15 00:00 |
08:40:35.46 |
+69:30:34.3 |
HIP 42652 |
8.13 |
| 2026-08-15 12:00 |
08:40:39.37 |
+69:30:35.6 |
HIP 42652 |
7.94 |
| 2026-08-16 00:00 |
08:40:43.26 |
+69:30:37.2 |
HIP 42652 |
7.75 |
| 2026-08-16 12:00 |
08:40:47.15 |
+69:30:38.8 |
HIP 42652 |
7.58 |
| 2026-08-17 00:00 |
08:40:51.03 |
+69:30:40.6 |
HIP 42652 |
7.43 |
| 2026-08-17 12:00 |
08:40:54.90 |
+69:30:42.6 |
HIP 42652 |
7.29 |
| 2026-08-18 00:00 |
08:40:58.76 |
+69:30:44.7 |
HIP 42652 |
7.16 |
| 2026-08-18 12:00 |
08:41:02.61 |
+69:30:46.9 |
HIP 42652 |
7.06 |
| 2026-08-19 00:00 |
08:41:06.45 |
+69:30:49.3 |
HIP 42652 |
6.97 |