| Parameter |
Value |
| Designation |
C/1978 C1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1978-03-17T16:34:51.617280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:27Z |
| Obs used |
73 |
| NEO |
- |
| M1 |
6.800 |
| K1 |
9.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1978-02-23.0000000 |
| e |
1.00000000 |
| q (au) |
0.436574 |
| a (au) |
- |
| i (deg) |
51.086724 |
| Ω (om, deg) |
260.497948 |
| ω (w, deg) |
48.706509 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (7.306 + 3.467\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.306 |
| n |
3.467 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.971 |
| 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 |
07:00:56.57 |
-07:10:15.1 |
HIP 33840 |
16.14 |
| 2026-05-12 12:00 |
07:00:57.52 |
-07:10:07.1 |
HIP 33840 |
15.90 |
| 2026-05-13 00:00 |
07:00:58.49 |
-07:09:59.3 |
HIP 33840 |
15.67 |
| 2026-05-13 12:00 |
07:00:59.46 |
-07:09:51.5 |
HIP 33840 |
15.44 |
| 2026-05-14 00:00 |
07:01:00.44 |
-07:09:43.8 |
HIP 33840 |
15.21 |
| 2026-05-14 12:00 |
07:01:01.44 |
-07:09:36.1 |
HIP 33840 |
14.98 |
| 2026-05-15 00:00 |
07:01:02.44 |
-07:09:28.6 |
HIP 33840 |
14.76 |
| 2026-05-15 12:00 |
07:01:03.45 |
-07:09:21.1 |
HIP 33840 |
14.53 |
| 2026-05-16 00:00 |
07:01:04.48 |
-07:09:13.7 |
HIP 33840 |
14.31 |
| 2026-05-16 12:00 |
07:01:05.51 |
-07:09:06.4 |
HIP 33840 |
14.09 |
| 2026-05-17 00:00 |
07:01:06.56 |
-07:08:59.1 |
HIP 33840 |
13.87 |
| 2026-05-17 12:00 |
07:01:07.61 |
-07:08:52.0 |
HIP 33840 |
13.66 |
| 2026-05-18 00:00 |
07:01:08.67 |
-07:08:44.9 |
HIP 33840 |
13.45 |
| 2026-05-18 12:00 |
07:01:09.75 |
-07:08:37.9 |
HIP 33840 |
13.24 |
| 2026-05-19 00:00 |
07:01:10.83 |
-07:08:31.0 |
HIP 33840 |
13.03 |
| 2026-05-19 12:00 |
07:01:11.92 |
-07:08:24.2 |
HIP 33840 |
12.83 |
| 2026-05-20 00:00 |
07:01:13.02 |
-07:08:17.4 |
HIP 33840 |
12.64 |
| 2026-05-20 12:00 |
07:01:14.14 |
-07:08:10.8 |
HIP 33840 |
12.44 |
| 2026-05-21 00:00 |
07:01:15.26 |
-07:08:04.2 |
HIP 33840 |
12.26 |
| 2026-05-21 12:00 |
07:01:16.39 |
-07:07:57.7 |
HIP 33840 |
12.08 |
| 2026-05-22 00:00 |
07:01:17.52 |
-07:07:51.3 |
HIP 33840 |
11.90 |
| 2026-05-22 12:00 |
07:01:18.67 |
-07:07:45.0 |
HIP 33840 |
11.73 |
| 2026-05-23 00:00 |
07:01:19.83 |
-07:07:38.8 |
HIP 33840 |
11.57 |
| 2026-05-23 12:00 |
07:01:20.99 |
-07:07:32.7 |
HIP 33840 |
11.41 |
| 2026-05-24 00:00 |
07:01:22.17 |
-07:07:26.6 |
HIP 33840 |
11.26 |
| 2026-05-24 12:00 |
07:01:23.35 |
-07:07:20.7 |
HIP 33840 |
11.12 |
| 2026-05-25 00:00 |
07:01:24.54 |
-07:07:14.8 |
HIP 33840 |
10.98 |
| 2026-05-25 12:00 |
07:01:25.74 |
-07:07:09.0 |
HIP 33840 |
10.86 |
| 2026-05-26 00:00 |
07:01:26.95 |
-07:07:03.3 |
HIP 33840 |
10.74 |
| 2026-05-26 12:00 |
07:01:28.16 |
-07:06:57.7 |
HIP 33840 |
10.63 |
| 2026-05-27 00:00 |
07:01:29.39 |
-07:06:52.2 |
HIP 33840 |
10.54 |
| 2026-05-27 12:00 |
07:01:30.62 |
-07:06:46.7 |
HIP 33840 |
10.45 |
| 2026-05-28 00:00 |
07:01:31.86 |
-07:06:41.4 |
HIP 33840 |
10.37 |
| 2026-05-28 12:00 |
07:01:33.11 |
-07:06:36.1 |
HIP 33840 |
10.31 |
| 2026-05-29 00:00 |
07:01:34.36 |
-07:06:31.0 |
HIP 33840 |
10.26 |
| 2026-05-29 12:00 |
07:01:35.63 |
-07:06:25.9 |
HIP 33840 |
10.21 |
| 2026-05-30 00:00 |
07:01:36.90 |
-07:06:20.9 |
HIP 33840 |
10.18 |
| 2026-05-30 12:00 |
07:01:38.18 |
-07:06:16.0 |
HIP 33840 |
10.17 |
| 2026-05-31 00:00 |
07:01:39.46 |
-07:06:11.2 |
HIP 33840 |
10.16 |
| 2026-05-31 12:00 |
07:01:40.75 |
-07:06:06.5 |
HIP 33840 |
10.17 |
| 2026-06-01 00:00 |
07:01:42.06 |
-07:06:01.9 |
HIP 33840 |
10.19 |
| 2026-06-01 12:00 |
07:01:43.36 |
-07:05:57.4 |
HIP 33840 |
10.22 |
| 2026-06-02 00:00 |
07:01:44.68 |
-07:05:52.9 |
HIP 33840 |
10.27 |