| Parameter |
Value |
| Designation |
381P/LINEAR-Spacewatch |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-09-29T17:41:23.599680Z |
| Orbit solution date (soln_date, UTC) |
2021-05-02T23:43:03Z |
| Obs used |
175 |
| NEO |
- |
| M1 |
13.600 |
| K1 |
14.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-05-29T13:47:59.136000Z |
| Discovery magnitude (MPC) |
21.60 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-07-10.0000000 |
| e |
0.67945045 |
| q (au) |
2.283195 |
| a (au) |
7.122754 |
| i (deg) |
28.462310 |
| Ω (om, deg) |
174.108452 |
| ω (w, deg) |
172.544217 |
| M (ma, deg) |
280.012136 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.792 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.792 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.831 |
| k |
0.996 |
| 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) |
| 2026-07-29 00:00 |
10:07:58.98 |
+02:03:18.6 |
HIP 49756 |
28.38 |
| 2026-07-29 12:00 |
10:08:08.87 |
+02:02:44.8 |
HIP 49756 |
27.00 |
| 2026-07-30 00:00 |
10:08:18.78 |
+02:02:10.6 |
HIP 49756 |
25.79 |
| 2026-07-30 12:00 |
10:08:28.72 |
+02:01:36.2 |
HIP 49756 |
24.79 |
| 2026-07-31 00:00 |
10:08:38.67 |
+02:01:01.4 |
HIP 49756 |
24.02 |
| 2026-07-31 12:00 |
10:08:48.65 |
+02:00:26.3 |
HIP 49756 |
23.50 |
| 2026-08-01 00:00 |
10:08:58.65 |
+01:59:50.9 |
HIP 49756 |
23.26 |
| 2026-08-01 12:00 |
10:09:08.67 |
+01:59:15.1 |
HIP 49777 |
23.15 |
| 2026-08-02 00:00 |
10:09:18.71 |
+01:58:39.1 |
HIP 49777 |
23.03 |
| 2026-08-02 12:00 |
10:09:28.78 |
+01:58:02.7 |
HIP 49777 |
23.20 |
| 2026-08-03 00:00 |
10:09:38.86 |
+01:57:26.0 |
HIP 49777 |
23.66 |
| 2026-08-03 12:00 |
10:09:48.96 |
+01:56:49.0 |
HIP 49777 |
24.40 |
| 2026-08-04 00:00 |
10:09:59.08 |
+01:56:11.7 |
HIP 49777 |
25.38 |
| 2026-08-04 12:00 |
10:10:09.22 |
+01:55:34.1 |
HIP 49777 |
26.60 |
| 2026-08-05 00:00 |
10:10:19.38 |
+01:54:56.2 |
HIP 49777 |
28.01 |
| 2026-08-05 12:00 |
10:10:29.55 |
+01:54:18.0 |
HIP 49777 |
29.59 |
| 2026-08-06 00:00 |
10:10:39.74 |
+01:53:39.5 |
HIP 49777 |
31.31 |
| 2026-08-06 12:00 |
10:10:49.95 |
+01:53:00.7 |
HIP 49777 |
33.16 |
| 2026-08-07 00:00 |
10:11:00.18 |
+01:52:21.5 |
HIP 49777 |
35.12 |
| 2026-08-07 12:00 |
10:11:10.42 |
+01:51:42.1 |
HIP 49777 |
37.17 |
| 2026-08-08 00:00 |
10:11:20.68 |
+01:51:02.5 |
HIP 49777 |
39.29 |
| 2026-08-08 12:00 |
10:11:30.95 |
+01:50:22.5 |
HIP 49777 |
41.48 |
| 2026-08-09 00:00 |
10:11:41.24 |
+01:49:42.2 |
HIP 49777 |
43.73 |
| 2026-08-09 12:00 |
10:11:51.54 |
+01:49:01.7 |
HIP 49777 |
46.03 |
| 2026-08-10 00:00 |
10:12:01.86 |
+01:48:20.8 |
HIP 49777 |
48.37 |
| 2026-08-10 12:00 |
10:12:12.18 |
+01:47:39.7 |
HIP 49777 |
50.75 |
| 2026-08-11 00:00 |
10:12:22.53 |
+01:46:58.3 |
HIP 49857 |
51.84 |
| 2026-08-11 12:00 |
10:12:32.88 |
+01:46:16.7 |
HIP 49857 |
52.41 |
| 2026-08-12 00:00 |
10:12:43.24 |
+01:45:34.7 |
HIP 49857 |
53.11 |
| 2026-08-12 12:00 |
10:12:53.62 |
+01:44:52.5 |
HIP 49857 |
53.92 |
| 2026-08-13 00:00 |
10:13:04.01 |
+01:44:10.1 |
HIP 49857 |
54.86 |
| 2026-08-13 12:00 |
10:13:14.40 |
+01:43:27.4 |
HIP 50348 |
54.46 |
| 2026-08-14 00:00 |
10:13:24.81 |
+01:42:44.4 |
HIP 50348 |
51.94 |
| 2026-08-14 12:00 |
10:13:35.22 |
+01:42:01.2 |
HIP 50348 |
49.43 |
| 2026-08-15 00:00 |
10:13:45.65 |
+01:41:17.7 |
HIP 50348 |
46.94 |
| 2026-08-15 12:00 |
10:13:56.08 |
+01:40:34.0 |
HIP 50348 |
44.47 |
| 2026-08-16 00:00 |
10:14:06.52 |
+01:39:50.0 |
HIP 50348 |
42.04 |
| 2026-08-16 12:00 |
10:14:16.97 |
+01:39:05.8 |
HIP 50348 |
39.63 |
| 2026-08-17 00:00 |
10:14:27.42 |
+01:38:21.3 |
HIP 50348 |
37.27 |
| 2026-08-17 12:00 |
10:14:37.88 |
+01:37:36.6 |
HIP 50348 |
34.96 |
| 2026-08-18 00:00 |
10:14:48.34 |
+01:36:51.7 |
HIP 50348 |
32.72 |
| 2026-08-18 12:00 |
10:14:58.81 |
+01:36:06.5 |
HIP 50348 |
30.55 |
| 2026-08-19 00:00 |
10:15:09.29 |
+01:35:21.1 |
HIP 50348 |
28.47 |