311P/PANSTARRS
| Parameter |
Value |
| Designation |
311P/PANSTARRS |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-07-10T16:19:53.999040Z |
| Orbit solution date (soln_date, UTC) |
2025-05-08T09:42:30Z |
| Obs used |
272 |
| NEO |
- |
| M1 |
19.000 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-04-29.0000000 |
| e |
0.11566755 |
| q (au) |
1.935566 |
| a (au) |
2.188731 |
| i (deg) |
4.966451 |
| Ω (om, deg) |
279.259757 |
| ω (w, deg) |
143.998566 |
| M (ma, deg) |
337.877546 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.434 + 2.034\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.434 |
| n |
2.034 |
| gf |
0.800 |
| gb |
-0.702 |
| k |
0.976 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
19:44:01.56 |
-20:50:38.3 |
HIP 97130 |
6.85 |
| 2026-02-03 12:00 |
19:45:01.47 |
-20:47:38.4 |
HIP 97130 |
8.04 |
| 2026-02-04 00:00 |
19:46:01.32 |
-20:44:37.1 |
HIP 97130 |
22.18 |
| 2026-02-04 12:00 |
19:47:01.13 |
-20:41:34.4 |
HIP 97417 |
21.01 |
| 2026-02-05 00:00 |
19:48:00.88 |
-20:38:30.4 |
HIP 97522 |
18.07 |
| 2026-02-05 12:00 |
19:49:00.58 |
-20:35:25.1 |
HIP 97522 |
8.75 |
| 2026-02-06 00:00 |
19:50:00.23 |
-20:32:18.4 |
HIP 97559 |
12.95 |
| 2026-02-06 12:00 |
19:50:59.83 |
-20:29:10.4 |
HIP 97559 |
23.46 |
| 2026-02-07 00:00 |
19:51:59.37 |
-20:26:01.1 |
HIP 97899 |
24.74 |
| 2026-02-07 12:00 |
19:52:58.86 |
-20:22:50.5 |
HIP 97899 |
10.51 |
| 2026-02-08 00:00 |
19:53:58.30 |
-20:19:38.5 |
HIP 97899 |
4.21 |
| 2026-02-08 12:00 |
19:54:57.68 |
-20:16:25.2 |
HIP 97899 |
18.26 |
| 2026-02-09 00:00 |
19:55:57.00 |
-20:13:10.6 |
HIP 98084 |
16.37 |
| 2026-02-09 12:00 |
19:56:56.27 |
-20:09:54.7 |
HIP 98140 |
18.99 |
| 2026-02-10 00:00 |
19:57:55.49 |
-20:06:37.5 |
HIP 98329 |
14.81 |
| 2026-02-10 12:00 |
19:58:54.65 |
-20:03:19.0 |
HIP 98329 |
8.00 |
| 2026-02-11 00:00 |
19:59:53.75 |
-19:59:59.3 |
HIP 98489 |
12.24 |
| 2026-02-11 12:00 |
20:00:52.79 |
-19:56:38.2 |
HIP 98489 |
7.32 |
| 2026-02-12 00:00 |
20:01:51.78 |
-19:53:15.9 |
HIP 98489 |
19.09 |
| 2026-02-12 12:00 |
20:02:50.70 |
-19:49:52.3 |
HIP 98489 |
32.90 |
| 2026-02-13 00:00 |
20:03:49.57 |
-19:46:27.5 |
HIP 99039 |
43.38 |
| 2026-02-13 12:00 |
20:04:48.38 |
-19:43:01.3 |
HIP 99039 |
34.71 |
| 2026-02-14 00:00 |
20:05:47.12 |
-19:39:34.0 |
HIP 99118 |
22.69 |
| 2026-02-14 12:00 |
20:06:45.81 |
-19:36:05.4 |
HIP 99118 |
8.45 |
| 2026-02-15 00:00 |
20:07:44.43 |
-19:32:35.5 |
HIP 99118 |
5.81 |
| 2026-02-15 12:00 |
20:08:42.99 |
-19:29:04.4 |
HIP 99118 |
20.05 |
| 2026-02-16 00:00 |
20:09:41.49 |
-19:25:32.1 |
HIP 99391 |
10.68 |
| 2026-02-16 12:00 |
20:10:39.92 |
-19:21:58.6 |
HIP 99391 |
3.56 |
| 2026-02-17 00:00 |
20:11:38.29 |
-19:18:23.8 |
HIP 99391 |
17.78 |
| 2026-02-17 12:00 |
20:12:36.59 |
-19:14:47.9 |
HIP 99782 |
29.88 |
| 2026-02-18 00:00 |
20:13:34.83 |
-19:11:10.7 |
HIP 99782 |
16.09 |
| 2026-02-18 12:00 |
20:14:33.01 |
-19:07:32.4 |
HIP 99782 |
5.41 |
| 2026-02-19 00:00 |
20:15:31.11 |
-19:03:52.8 |
HIP 99782 |
14.26 |
| 2026-02-19 12:00 |
20:16:29.15 |
-19:00:12.1 |
HIP 99782 |
27.94 |
| 2026-02-20 00:00 |
20:17:27.12 |
-18:56:30.3 |
HIP 100107 |
25.50 |
| 2026-02-20 12:00 |
20:18:25.03 |
-18:52:47.2 |
HIP 100195 |
19.92 |
| 2026-02-21 00:00 |
20:19:22.86 |
-18:49:03.0 |
HIP 100195 |
18.06 |
| 2026-02-21 12:00 |
20:20:20.63 |
-18:45:17.6 |
HIP 100195 |
25.65 |
| 2026-02-22 00:00 |
20:21:18.32 |
-18:41:31.1 |
HIP 100348 |
22.45 |
| 2026-02-22 12:00 |
20:22:15.95 |
-18:37:43.5 |
HIP 100533 |
21.13 |
| 2026-02-23 00:00 |
20:23:13.50 |
-18:33:54.7 |
HIP 100533 |
13.43 |
| 2026-02-23 12:00 |
20:24:10.98 |
-18:30:04.8 |
HIP 100533 |
17.76 |
| 2026-02-24 00:00 |
20:25:08.40 |
-18:26:13.8 |
HIP 100770 |
11.15 |