| 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) |
| 2026-09-20 00:00 |
10:26:08.76 |
+00:41:10.9 |
HIP 51034 |
25.25 |
| 2026-09-20 12:00 |
10:26:18.56 |
+00:40:16.9 |
HIP 51034 |
26.99 |
| 2026-09-21 00:00 |
10:26:28.34 |
+00:39:22.8 |
HIP 51034 |
28.86 |
| 2026-09-21 12:00 |
10:26:38.09 |
+00:38:28.7 |
HIP 51285 |
29.17 |
| 2026-09-22 00:00 |
10:26:47.81 |
+00:37:34.6 |
HIP 51285 |
26.60 |
| 2026-09-22 12:00 |
10:26:57.50 |
+00:36:40.5 |
HIP 51285 |
24.03 |
| 2026-09-23 00:00 |
10:27:07.17 |
+00:35:46.3 |
HIP 51285 |
21.48 |
| 2026-09-23 12:00 |
10:27:16.81 |
+00:34:52.2 |
HIP 51285 |
18.94 |
| 2026-09-24 00:00 |
10:27:26.42 |
+00:33:58.0 |
HIP 51285 |
16.42 |
| 2026-09-24 12:00 |
10:27:36.00 |
+00:33:03.8 |
HIP 51285 |
13.93 |
| 2026-09-25 00:00 |
10:27:45.55 |
+00:32:09.6 |
HIP 51285 |
11.47 |
| 2026-09-25 12:00 |
10:27:55.07 |
+00:31:15.5 |
HIP 51285 |
9.07 |
| 2026-09-26 00:00 |
10:28:04.56 |
+00:30:21.3 |
HIP 51285 |
6.79 |
| 2026-09-26 12:00 |
10:28:14.03 |
+00:29:27.1 |
HIP 51285 |
4.79 |
| 2026-09-27 00:00 |
10:28:23.46 |
+00:28:33.0 |
HIP 51285 |
3.54 |
| 2026-09-27 12:00 |
10:28:32.85 |
+00:27:38.8 |
HIP 51285 |
3.85 |
| 2026-09-28 00:00 |
10:28:42.22 |
+00:26:44.7 |
HIP 51285 |
5.46 |
| 2026-09-28 12:00 |
10:28:51.55 |
+00:25:50.6 |
HIP 51285 |
7.57 |
| 2026-09-29 00:00 |
10:29:00.85 |
+00:24:56.5 |
HIP 51285 |
9.86 |
| 2026-09-29 12:00 |
10:29:10.12 |
+00:24:02.4 |
HIP 51285 |
12.22 |
| 2026-09-30 00:00 |
10:29:19.36 |
+00:23:08.3 |
HIP 51285 |
14.61 |
| 2026-09-30 12:00 |
10:29:28.56 |
+00:22:14.3 |
HIP 51285 |
17.03 |
| 2026-10-01 00:00 |
10:29:37.72 |
+00:21:20.3 |
HIP 51285 |
19.44 |
| 2026-10-01 12:00 |
10:29:46.85 |
+00:20:26.4 |
HIP 51285 |
21.86 |
| 2026-10-02 00:00 |
10:29:55.95 |
+00:19:32.5 |
HIP 51285 |
24.28 |
| 2026-10-02 12:00 |
10:30:05.01 |
+00:18:38.6 |
HIP 51285 |
26.70 |
| 2026-10-03 00:00 |
10:30:14.03 |
+00:17:44.8 |
HIP 51559 |
27.68 |
| 2026-10-03 12:00 |
10:30:23.01 |
+00:16:51.0 |
HIP 51559 |
26.01 |
| 2026-10-04 00:00 |
10:30:31.96 |
+00:15:57.3 |
HIP 51559 |
24.48 |
| 2026-10-04 12:00 |
10:30:40.87 |
+00:15:03.7 |
HIP 51559 |
23.11 |
| 2026-10-05 00:00 |
10:30:49.74 |
+00:14:10.1 |
HIP 51559 |
21.92 |
| 2026-10-05 12:00 |
10:30:58.58 |
+00:13:16.5 |
HIP 51559 |
20.95 |
| 2026-10-06 00:00 |
10:31:07.37 |
+00:12:23.1 |
HIP 51559 |
20.21 |
| 2026-10-06 12:00 |
10:31:16.12 |
+00:11:29.7 |
HIP 51559 |
19.74 |
| 2026-10-07 00:00 |
10:31:24.84 |
+00:10:36.4 |
HIP 51559 |
19.54 |
| 2026-10-07 12:00 |
10:31:33.51 |
+00:09:43.2 |
HIP 51559 |
19.63 |
| 2026-10-08 00:00 |
10:31:42.14 |
+00:08:50.0 |
HIP 51559 |
20.00 |
| 2026-10-08 12:00 |
10:31:50.73 |
+00:07:56.9 |
HIP 51559 |
20.62 |
| 2026-10-09 00:00 |
10:31:59.27 |
+00:07:04.0 |
HIP 51559 |
21.48 |
| 2026-10-09 12:00 |
10:32:07.78 |
+00:06:11.1 |
HIP 51559 |
22.54 |
| 2026-10-10 00:00 |
10:32:16.24 |
+00:05:18.3 |
HIP 51559 |
23.77 |
| 2026-10-10 12:00 |
10:32:24.65 |
+00:04:25.7 |
HIP 51559 |
25.14 |
| 2026-10-11 00:00 |
10:32:33.02 |
+00:03:33.1 |
HIP 51559 |
26.64 |