| Parameter |
Value |
| Designation |
C/1979 Y1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1979-12-21T14:38:01.069440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
127 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
14.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1980-01-25.0000000 |
| e |
0.98803814 |
| q (au) |
0.545301 |
| a (au) |
45.586646 |
| i (deg) |
148.602533 |
| Ω (om, deg) |
103.215535 |
| ω (w, deg) |
257.609730 |
| M (ma, deg) |
0.110124 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.331 + 4.383\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.331 |
| n |
4.383 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 1979-12-26 |
1980-01-04 |
+1.4679 |
-0.064 |
| 1980-01-04 |
1980-01-25 |
+5.5414 |
+0.963 |
| 1980-01-25 |
1980-03-02 |
-4.9082 |
+0.307 |
| 1980-03-02 |
1980-03-17 |
-4.0819 |
-0.038 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
01:24:28.91 |
+40:30:00.8 |
HIP 6469 |
15.89 |
| 2026-06-01 12:00 |
01:24:30.47 |
+40:30:18.1 |
HIP 6469 |
16.04 |
| 2026-06-02 00:00 |
01:24:32.01 |
+40:30:35.4 |
HIP 6469 |
16.20 |
| 2026-06-02 12:00 |
01:24:33.55 |
+40:30:52.7 |
HIP 6469 |
16.37 |
| 2026-06-03 00:00 |
01:24:35.06 |
+40:31:10.0 |
HIP 6469 |
16.54 |
| 2026-06-03 12:00 |
01:24:36.57 |
+40:31:27.4 |
HIP 6469 |
16.72 |
| 2026-06-04 00:00 |
01:24:38.05 |
+40:31:44.8 |
HIP 6469 |
16.90 |
| 2026-06-04 12:00 |
01:24:39.53 |
+40:32:02.2 |
HIP 6469 |
17.09 |
| 2026-06-05 00:00 |
01:24:40.99 |
+40:32:19.7 |
HIP 6469 |
17.28 |
| 2026-06-05 12:00 |
01:24:42.43 |
+40:32:37.1 |
HIP 6469 |
17.47 |
| 2026-06-06 00:00 |
01:24:43.86 |
+40:32:54.6 |
HIP 6469 |
17.67 |
| 2026-06-06 12:00 |
01:24:45.27 |
+40:33:12.1 |
HIP 6469 |
17.88 |
| 2026-06-07 00:00 |
01:24:46.67 |
+40:33:29.6 |
HIP 6469 |
18.08 |
| 2026-06-07 12:00 |
01:24:48.05 |
+40:33:47.2 |
HIP 6469 |
18.29 |
| 2026-06-08 00:00 |
01:24:49.41 |
+40:34:04.7 |
HIP 6469 |
18.51 |
| 2026-06-08 12:00 |
01:24:50.76 |
+40:34:22.3 |
HIP 6469 |
18.72 |
| 2026-06-09 00:00 |
01:24:52.10 |
+40:34:39.9 |
HIP 6469 |
18.94 |
| 2026-06-09 12:00 |
01:24:53.42 |
+40:34:57.5 |
HIP 6469 |
19.16 |
| 2026-06-10 00:00 |
01:24:54.72 |
+40:35:15.1 |
HIP 6469 |
19.38 |
| 2026-06-10 12:00 |
01:24:56.01 |
+40:35:32.7 |
HIP 6469 |
19.61 |
| 2026-06-11 00:00 |
01:24:57.28 |
+40:35:50.3 |
HIP 6469 |
19.83 |
| 2026-06-11 12:00 |
01:24:58.53 |
+40:36:08.0 |
HIP 6469 |
20.06 |
| 2026-06-12 00:00 |
01:24:59.77 |
+40:36:25.6 |
HIP 6469 |
20.29 |
| 2026-06-12 12:00 |
01:25:00.99 |
+40:36:43.3 |
HIP 6469 |
20.52 |
| 2026-06-13 00:00 |
01:25:02.19 |
+40:37:00.9 |
HIP 6469 |
20.75 |
| 2026-06-13 12:00 |
01:25:03.38 |
+40:37:18.6 |
HIP 6469 |
20.98 |
| 2026-06-14 00:00 |
01:25:04.55 |
+40:37:36.3 |
HIP 6469 |
21.22 |
| 2026-06-14 12:00 |
01:25:05.70 |
+40:37:53.9 |
HIP 6469 |
21.45 |
| 2026-06-15 00:00 |
01:25:06.84 |
+40:38:11.6 |
HIP 6469 |
21.68 |
| 2026-06-15 12:00 |
01:25:07.96 |
+40:38:29.2 |
HIP 6469 |
21.92 |
| 2026-06-16 00:00 |
01:25:09.06 |
+40:38:46.9 |
HIP 6469 |
22.15 |
| 2026-06-16 12:00 |
01:25:10.14 |
+40:39:04.5 |
HIP 6469 |
22.39 |
| 2026-06-17 00:00 |
01:25:11.21 |
+40:39:22.2 |
HIP 6469 |
22.62 |
| 2026-06-17 12:00 |
01:25:12.26 |
+40:39:39.8 |
HIP 6469 |
22.85 |
| 2026-06-18 00:00 |
01:25:13.29 |
+40:39:57.4 |
HIP 6469 |
23.09 |
| 2026-06-18 12:00 |
01:25:14.30 |
+40:40:15.1 |
HIP 6469 |
23.32 |
| 2026-06-19 00:00 |
01:25:15.30 |
+40:40:32.7 |
HIP 6469 |
23.55 |
| 2026-06-19 12:00 |
01:25:16.27 |
+40:40:50.3 |
HIP 6469 |
23.79 |
| 2026-06-20 00:00 |
01:25:17.23 |
+40:41:07.8 |
HIP 6469 |
24.02 |
| 2026-06-20 12:00 |
01:25:18.17 |
+40:41:25.4 |
HIP 6469 |
24.25 |
| 2026-06-21 00:00 |
01:25:19.10 |
+40:41:43.0 |
HIP 6469 |
24.48 |
| 2026-06-21 12:00 |
01:25:20.00 |
+40:42:00.5 |
HIP 6469 |
24.71 |
| 2026-06-22 00:00 |
01:25:20.89 |
+40:42:18.0 |
HIP 6469 |
24.94 |