| Parameter |
Value |
| Designation |
289P/Blanpain |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-12-20T23:47:39.655680Z |
| Orbit solution date (soln_date, UTC) |
2025-05-23T12:29:45Z |
| Obs used |
356 |
| NEO |
Yes |
| M1 |
22.000 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-09-19.0000000 |
| e |
0.68514009 |
| q (au) |
0.958876 |
| a (au) |
3.045405 |
| i (deg) |
5.897388 |
| Ω (om, deg) |
68.924004 |
| ω (w, deg) |
9.849290 |
| M (ma, deg) |
342.754359 |
Magnitude
Scatter + Global Linear
$$
M_a = (18.699 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
18.699 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.501 |
| 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) |
| 2026-05-12 00:00 |
14:46:37.30 |
-12:40:43.2 |
HIP 72373 |
21.25 |
| 2026-05-12 12:00 |
14:46:10.07 |
-12:39:07.7 |
HIP 72174 |
18.97 |
| 2026-05-13 00:00 |
14:45:42.97 |
-12:37:32.8 |
HIP 72174 |
16.33 |
| 2026-05-13 12:00 |
14:45:15.99 |
-12:35:58.4 |
HIP 72174 |
16.31 |
| 2026-05-14 00:00 |
14:44:49.14 |
-12:34:24.8 |
HIP 72174 |
18.88 |
| 2026-05-14 12:00 |
14:44:22.43 |
-12:32:51.8 |
HIP 72174 |
23.16 |
| 2026-05-15 00:00 |
14:43:55.85 |
-12:31:19.4 |
HIP 72174 |
28.37 |
| 2026-05-15 12:00 |
14:43:29.41 |
-12:29:47.7 |
HIP 71873 |
26.45 |
| 2026-05-16 00:00 |
14:43:03.12 |
-12:28:16.8 |
HIP 71873 |
20.55 |
| 2026-05-16 12:00 |
14:42:36.99 |
-12:26:46.6 |
HIP 71873 |
15.26 |
| 2026-05-17 00:00 |
14:42:11.01 |
-12:25:17.1 |
HIP 71873 |
11.39 |
| 2026-05-17 12:00 |
14:41:45.19 |
-12:23:48.4 |
HIP 71873 |
10.57 |
| 2026-05-18 00:00 |
14:41:19.53 |
-12:22:20.5 |
HIP 71873 |
13.30 |
| 2026-05-18 12:00 |
14:40:54.04 |
-12:20:53.4 |
HIP 71873 |
18.00 |
| 2026-05-19 00:00 |
14:40:28.73 |
-12:19:27.2 |
HIP 71873 |
23.47 |
| 2026-05-19 12:00 |
14:40:03.59 |
-12:18:01.8 |
HIP 71873 |
29.26 |
| 2026-05-20 00:00 |
14:39:38.63 |
-12:16:37.2 |
HIP 71873 |
35.18 |
| 2026-05-20 12:00 |
14:39:13.86 |
-12:15:13.5 |
HIP 71469 |
32.78 |
| 2026-05-21 00:00 |
14:38:49.27 |
-12:13:50.8 |
HIP 71469 |
27.00 |
| 2026-05-21 12:00 |
14:38:24.88 |
-12:12:28.9 |
HIP 71469 |
21.49 |
| 2026-05-22 00:00 |
14:38:00.68 |
-12:11:08.0 |
HIP 71469 |
16.43 |
| 2026-05-22 12:00 |
14:37:36.68 |
-12:09:48.0 |
HIP 71469 |
12.35 |
| 2026-05-23 00:00 |
14:37:12.88 |
-12:08:29.0 |
HIP 71469 |
10.36 |
| 2026-05-23 12:00 |
14:36:49.28 |
-12:07:10.9 |
HIP 71469 |
11.51 |
| 2026-05-24 00:00 |
14:36:25.89 |
-12:05:53.8 |
HIP 71469 |
15.04 |
| 2026-05-24 12:00 |
14:36:02.72 |
-12:04:37.8 |
HIP 71469 |
19.67 |
| 2026-05-25 00:00 |
14:35:39.75 |
-12:03:22.7 |
HIP 71340 |
19.11 |
| 2026-05-25 12:00 |
14:35:17.00 |
-12:02:08.7 |
HIP 71340 |
17.37 |
| 2026-05-26 00:00 |
14:34:54.47 |
-12:00:55.7 |
HIP 71340 |
17.40 |
| 2026-05-26 12:00 |
14:34:32.16 |
-11:59:43.7 |
HIP 71340 |
19.15 |
| 2026-05-27 00:00 |
14:34:10.07 |
-11:58:32.8 |
HIP 71340 |
22.18 |
| 2026-05-27 12:00 |
14:33:48.21 |
-11:57:23.0 |
HIP 71120 |
18.46 |
| 2026-05-28 00:00 |
14:33:26.58 |
-11:56:14.3 |
HIP 71120 |
13.11 |
| 2026-05-28 12:00 |
14:33:05.18 |
-11:55:06.6 |
HIP 71120 |
7.93 |
| 2026-05-29 00:00 |
14:32:44.01 |
-11:54:00.1 |
HIP 71120 |
3.36 |
| 2026-05-29 12:00 |
14:32:23.07 |
-11:52:54.7 |
HIP 71120 |
3.95 |
| 2026-05-30 00:00 |
14:32:02.38 |
-11:51:50.4 |
HIP 71120 |
8.59 |
| 2026-05-30 12:00 |
14:31:41.92 |
-11:50:47.2 |
HIP 71005 |
5.88 |
| 2026-05-31 00:00 |
14:31:21.70 |
-11:49:45.1 |
HIP 71005 |
2.57 |
| 2026-05-31 12:00 |
14:31:01.72 |
-11:48:44.3 |
HIP 71005 |
5.39 |
| 2026-06-01 00:00 |
14:30:41.99 |
-11:47:44.5 |
HIP 71005 |
10.00 |
| 2026-06-01 12:00 |
14:30:22.50 |
-11:46:46.0 |
HIP 71005 |
14.76 |
| 2026-06-02 00:00 |
14:30:03.26 |
-11:45:48.6 |
HIP 71005 |
19.51 |