| Parameter |
Value |
| Designation |
139P/Vaisala-Oterma |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2008-04-20T18:46:49.071360Z |
| Orbit solution date (soln_date, UTC) |
2026-07-28T14:32:31Z |
| Obs used |
564 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
18.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-03-18.0000000 |
| e |
0.24756210 |
| q (au) |
3.403367 |
| a (au) |
4.523120 |
| i (deg) |
2.329077 |
| Ω (om, deg) |
242.357941 |
| ω (w, deg) |
165.791035 |
| M (ma, deg) |
108.730494 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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 |
00:04:13.27 |
+03:24:20.7 |
HIP 239 |
18.75 |
| 2026-07-29 12:00 |
00:04:13.18 |
+03:24:36.9 |
HIP 239 |
18.75 |
| 2026-07-30 00:00 |
00:04:12.85 |
+03:24:51.5 |
HIP 239 |
18.69 |
| 2026-07-30 12:00 |
00:04:12.28 |
+03:25:04.6 |
HIP 239 |
18.57 |
| 2026-07-31 00:00 |
00:04:11.47 |
+03:25:16.0 |
HIP 239 |
18.40 |
| 2026-07-31 12:00 |
00:04:10.44 |
+03:25:25.8 |
HIP 239 |
18.16 |
| 2026-08-01 00:00 |
00:04:09.16 |
+03:25:34.1 |
HIP 239 |
17.87 |
| 2026-08-01 12:00 |
00:04:07.65 |
+03:25:40.7 |
HIP 239 |
17.51 |
| 2026-08-02 00:00 |
00:04:05.90 |
+03:25:45.7 |
HIP 239 |
17.09 |
| 2026-08-02 12:00 |
00:04:03.91 |
+03:25:49.1 |
HIP 239 |
16.61 |
| 2026-08-03 00:00 |
00:04:01.69 |
+03:25:50.8 |
HIP 239 |
16.07 |
| 2026-08-03 12:00 |
00:03:59.23 |
+03:25:51.0 |
HIP 239 |
15.47 |
| 2026-08-04 00:00 |
00:03:56.53 |
+03:25:49.5 |
HIP 239 |
14.81 |
| 2026-08-04 12:00 |
00:03:53.60 |
+03:25:46.3 |
HIP 239 |
14.08 |
| 2026-08-05 00:00 |
00:03:50.42 |
+03:25:41.6 |
HIP 239 |
13.29 |
| 2026-08-05 12:00 |
00:03:47.02 |
+03:25:35.2 |
HIP 239 |
12.43 |
| 2026-08-06 00:00 |
00:03:43.37 |
+03:25:27.1 |
HIP 239 |
11.51 |
| 2026-08-06 12:00 |
00:03:39.48 |
+03:25:17.4 |
HIP 239 |
10.53 |
| 2026-08-07 00:00 |
00:03:35.36 |
+03:25:06.1 |
HIP 239 |
9.49 |
| 2026-08-07 12:00 |
00:03:31.01 |
+03:24:53.1 |
HIP 239 |
8.38 |
| 2026-08-08 00:00 |
00:03:26.41 |
+03:24:38.4 |
HIP 239 |
7.21 |
| 2026-08-08 12:00 |
00:03:21.58 |
+03:24:22.1 |
HIP 239 |
5.97 |
| 2026-08-09 00:00 |
00:03:16.52 |
+03:24:04.2 |
HIP 239 |
4.68 |
| 2026-08-09 12:00 |
00:03:11.22 |
+03:23:44.6 |
HIP 239 |
3.31 |
| 2026-08-10 00:00 |
00:03:05.69 |
+03:23:23.3 |
HIP 239 |
1.89 |
| 2026-08-10 12:00 |
00:02:59.92 |
+03:23:00.4 |
HIP 239 |
0.40 |
| 2026-08-11 00:00 |
00:02:53.92 |
+03:22:35.8 |
HIP 239 |
1.15 |
| 2026-08-11 12:00 |
00:02:47.68 |
+03:22:09.6 |
HIP 239 |
2.77 |
| 2026-08-12 00:00 |
00:02:41.22 |
+03:21:41.8 |
HIP 239 |
4.45 |
| 2026-08-12 12:00 |
00:02:34.52 |
+03:21:12.3 |
HIP 239 |
6.19 |
| 2026-08-13 00:00 |
00:02:27.60 |
+03:20:41.1 |
HIP 239 |
7.99 |
| 2026-08-13 12:00 |
00:02:20.45 |
+03:20:08.4 |
HIP 239 |
9.86 |
| 2026-08-14 00:00 |
00:02:13.07 |
+03:19:34.0 |
HIP 239 |
11.79 |
| 2026-08-14 12:00 |
00:02:05.46 |
+03:18:57.9 |
HIP 239 |
13.78 |
| 2026-08-15 00:00 |
00:01:57.64 |
+03:18:20.3 |
HIP 239 |
15.83 |
| 2026-08-15 12:00 |
00:01:49.58 |
+03:17:41.0 |
HIP 239 |
17.94 |
| 2026-08-16 00:00 |
00:01:41.31 |
+03:17:00.2 |
HIP 239 |
20.12 |
| 2026-08-16 12:00 |
00:01:32.82 |
+03:16:17.7 |
HIP 239 |
22.35 |
| 2026-08-17 00:00 |
00:01:24.11 |
+03:15:33.6 |
HIP 239 |
24.65 |
| 2026-08-17 12:00 |
00:01:15.18 |
+03:14:48.0 |
HIP 239 |
27.00 |
| 2026-08-18 00:00 |
00:01:06.03 |
+03:14:00.7 |
HIP 239 |
29.41 |
| 2026-08-18 12:00 |
00:00:56.68 |
+03:13:11.9 |
HIP 239 |
31.89 |
| 2026-08-19 00:00 |
00:00:47.11 |
+03:12:21.6 |
HIP 31 |
32.37 |