| Parameter |
Value |
| Designation |
C/1976 D1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1976-02-24T15:11:04.778880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:24Z |
| Obs used |
29 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1976-03-08.0000000 |
| e |
0.99342533 |
| q (au) |
0.847793 |
| a (au) |
128.948233 |
| i (deg) |
46.830935 |
| Ω (om, deg) |
160.792814 |
| ω (w, deg) |
313.000258 |
| M (ma, deg) |
0.008324 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.846 + 2.217\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.846 |
| n |
2.217 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
1.000 |
| 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 |
19:19:31.32 |
+16:29:40.5 |
HIP 94991 |
3.50 |
| 2026-05-12 12:00 |
19:19:30.44 |
+16:29:52.1 |
HIP 94991 |
3.71 |
| 2026-05-13 00:00 |
19:19:29.55 |
+16:30:03.6 |
HIP 94991 |
3.92 |
| 2026-05-13 12:00 |
19:19:28.64 |
+16:30:15.0 |
HIP 94991 |
4.15 |
| 2026-05-14 00:00 |
19:19:27.72 |
+16:30:26.3 |
HIP 94991 |
4.39 |
| 2026-05-14 12:00 |
19:19:26.79 |
+16:30:37.5 |
HIP 94991 |
4.64 |
| 2026-05-15 00:00 |
19:19:25.85 |
+16:30:48.7 |
HIP 94991 |
4.89 |
| 2026-05-15 12:00 |
19:19:24.89 |
+16:30:59.7 |
HIP 94991 |
5.15 |
| 2026-05-16 00:00 |
19:19:23.93 |
+16:31:10.6 |
HIP 94991 |
5.42 |
| 2026-05-16 12:00 |
19:19:22.95 |
+16:31:21.5 |
HIP 94991 |
5.69 |
| 2026-05-17 00:00 |
19:19:21.96 |
+16:31:32.2 |
HIP 94991 |
5.97 |
| 2026-05-17 12:00 |
19:19:20.95 |
+16:31:42.9 |
HIP 94991 |
6.25 |
| 2026-05-18 00:00 |
19:19:19.94 |
+16:31:53.4 |
HIP 94991 |
6.53 |
| 2026-05-18 12:00 |
19:19:18.91 |
+16:32:03.9 |
HIP 94991 |
6.82 |
| 2026-05-19 00:00 |
19:19:17.87 |
+16:32:14.2 |
HIP 94991 |
7.11 |
| 2026-05-19 12:00 |
19:19:16.82 |
+16:32:24.5 |
HIP 94991 |
7.41 |
| 2026-05-20 00:00 |
19:19:15.76 |
+16:32:34.7 |
HIP 94991 |
7.70 |
| 2026-05-20 12:00 |
19:19:14.69 |
+16:32:44.7 |
HIP 94905 |
7.87 |
| 2026-05-21 00:00 |
19:19:13.61 |
+16:32:54.6 |
HIP 94905 |
7.71 |
| 2026-05-21 12:00 |
19:19:12.51 |
+16:33:04.5 |
HIP 94905 |
7.56 |
| 2026-05-22 00:00 |
19:19:11.41 |
+16:33:14.2 |
HIP 94905 |
7.42 |
| 2026-05-22 12:00 |
19:19:10.29 |
+16:33:23.9 |
HIP 94905 |
7.28 |
| 2026-05-23 00:00 |
19:19:09.17 |
+16:33:33.4 |
HIP 94905 |
7.15 |
| 2026-05-23 12:00 |
19:19:08.03 |
+16:33:42.8 |
HIP 94905 |
7.03 |
| 2026-05-24 00:00 |
19:19:06.88 |
+16:33:52.1 |
HIP 94905 |
6.92 |
| 2026-05-24 12:00 |
19:19:05.72 |
+16:34:01.3 |
HIP 94905 |
6.82 |
| 2026-05-25 00:00 |
19:19:04.55 |
+16:34:10.4 |
HIP 94905 |
6.73 |
| 2026-05-25 12:00 |
19:19:03.37 |
+16:34:19.4 |
HIP 94905 |
6.65 |
| 2026-05-26 00:00 |
19:19:02.19 |
+16:34:28.3 |
HIP 94905 |
6.58 |
| 2026-05-26 12:00 |
19:19:00.99 |
+16:34:37.1 |
HIP 94905 |
6.53 |
| 2026-05-27 00:00 |
19:18:59.78 |
+16:34:45.7 |
HIP 94905 |
6.48 |
| 2026-05-27 12:00 |
19:18:58.56 |
+16:34:54.3 |
HIP 94905 |
6.45 |
| 2026-05-28 00:00 |
19:18:57.33 |
+16:35:02.7 |
HIP 94905 |
6.44 |
| 2026-05-28 12:00 |
19:18:56.09 |
+16:35:11.0 |
HIP 94905 |
6.44 |
| 2026-05-29 00:00 |
19:18:54.84 |
+16:35:19.2 |
HIP 94905 |
6.45 |
| 2026-05-29 12:00 |
19:18:53.58 |
+16:35:27.3 |
HIP 94905 |
6.47 |
| 2026-05-30 00:00 |
19:18:52.31 |
+16:35:35.3 |
HIP 94905 |
6.51 |
| 2026-05-30 12:00 |
19:18:51.03 |
+16:35:43.2 |
HIP 94905 |
6.57 |
| 2026-05-31 00:00 |
19:18:49.75 |
+16:35:50.9 |
HIP 94905 |
6.64 |
| 2026-05-31 12:00 |
19:18:48.45 |
+16:35:58.6 |
HIP 94905 |
6.72 |
| 2026-06-01 00:00 |
19:18:47.15 |
+16:36:06.1 |
HIP 94905 |
6.81 |
| 2026-06-01 12:00 |
19:18:45.83 |
+16:36:13.5 |
HIP 94884 |
6.62 |
| 2026-06-02 00:00 |
19:18:44.51 |
+16:36:20.8 |
HIP 94884 |
6.35 |