| 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) |
| 2026-03-26 00:00 |
09:56:21.82 |
+00:35:09.3 |
HIP 48591 |
34.40 |
| 2026-03-26 12:00 |
09:56:15.30 |
+00:36:19.7 |
HIP 48591 |
32.40 |
| 2026-03-27 00:00 |
09:56:08.84 |
+00:37:30.0 |
HIP 48591 |
30.41 |
| 2026-03-27 12:00 |
09:56:02.44 |
+00:38:40.1 |
HIP 48591 |
28.43 |
| 2026-03-28 00:00 |
09:55:56.12 |
+00:39:50.0 |
HIP 48591 |
26.47 |
| 2026-03-28 12:00 |
09:55:49.86 |
+00:40:59.8 |
HIP 48591 |
24.52 |
| 2026-03-29 00:00 |
09:55:43.67 |
+00:42:09.4 |
HIP 48591 |
22.59 |
| 2026-03-29 12:00 |
09:55:37.54 |
+00:43:18.9 |
HIP 48591 |
20.67 |
| 2026-03-30 00:00 |
09:55:31.49 |
+00:44:28.1 |
HIP 48591 |
18.77 |
| 2026-03-30 12:00 |
09:55:25.50 |
+00:45:37.2 |
HIP 48591 |
16.88 |
| 2026-03-31 00:00 |
09:55:19.58 |
+00:46:46.1 |
HIP 48591 |
15.02 |
| 2026-03-31 12:00 |
09:55:13.74 |
+00:47:54.7 |
HIP 48591 |
13.16 |
| 2026-04-01 00:00 |
09:55:07.96 |
+00:49:03.2 |
HIP 48591 |
11.33 |
| 2026-04-01 12:00 |
09:55:02.25 |
+00:50:11.5 |
HIP 48591 |
9.50 |
| 2026-04-02 00:00 |
09:54:56.62 |
+00:51:19.5 |
HIP 48591 |
7.70 |
| 2026-04-02 12:00 |
09:54:51.06 |
+00:52:27.4 |
HIP 48591 |
5.92 |
| 2026-04-03 00:00 |
09:54:45.57 |
+00:53:35.0 |
HIP 48591 |
4.16 |
| 2026-04-03 12:00 |
09:54:40.15 |
+00:54:42.4 |
HIP 48591 |
2.43 |
| 2026-04-04 00:00 |
09:54:34.81 |
+00:55:49.5 |
HIP 48591 |
0.84 |
| 2026-04-04 12:00 |
09:54:29.54 |
+00:56:56.5 |
HIP 48591 |
1.25 |
| 2026-04-05 00:00 |
09:54:24.34 |
+00:58:03.1 |
HIP 48591 |
2.87 |
| 2026-04-05 12:00 |
09:54:19.22 |
+00:59:09.6 |
HIP 48591 |
4.54 |
| 2026-04-06 00:00 |
09:54:14.18 |
+01:00:15.7 |
HIP 48591 |
6.21 |
| 2026-04-06 12:00 |
09:54:09.21 |
+01:01:21.7 |
HIP 48591 |
7.86 |
| 2026-04-07 00:00 |
09:54:04.31 |
+01:02:27.3 |
HIP 48591 |
9.49 |
| 2026-04-07 12:00 |
09:53:59.49 |
+01:03:32.7 |
HIP 48591 |
11.11 |
| 2026-04-08 00:00 |
09:53:54.75 |
+01:04:37.8 |
HIP 48591 |
12.72 |
| 2026-04-08 12:00 |
09:53:50.09 |
+01:05:42.7 |
HIP 48591 |
14.30 |
| 2026-04-09 00:00 |
09:53:45.50 |
+01:06:47.2 |
HIP 48591 |
15.87 |
| 2026-04-09 12:00 |
09:53:40.99 |
+01:07:51.5 |
HIP 48591 |
17.42 |
| 2026-04-10 00:00 |
09:53:36.56 |
+01:08:55.5 |
HIP 48591 |
18.96 |
| 2026-04-10 12:00 |
09:53:32.21 |
+01:09:59.2 |
HIP 48591 |
20.47 |
| 2026-04-11 00:00 |
09:53:27.94 |
+01:11:02.6 |
HIP 48591 |
21.97 |
| 2026-04-11 12:00 |
09:53:23.75 |
+01:12:05.7 |
HIP 48591 |
23.45 |
| 2026-04-12 00:00 |
09:53:19.64 |
+01:13:08.4 |
HIP 48591 |
24.92 |
| 2026-04-12 12:00 |
09:53:15.60 |
+01:14:10.9 |
HIP 48591 |
26.36 |
| 2026-04-13 00:00 |
09:53:11.65 |
+01:15:13.0 |
HIP 48591 |
27.79 |
| 2026-04-13 12:00 |
09:53:07.78 |
+01:16:14.8 |
HIP 48591 |
29.19 |
| 2026-04-14 00:00 |
09:53:03.99 |
+01:17:16.3 |
HIP 48591 |
30.58 |
| 2026-04-14 12:00 |
09:53:00.28 |
+01:18:17.4 |
HIP 48591 |
31.96 |
| 2026-04-15 00:00 |
09:52:56.66 |
+01:19:18.2 |
HIP 48591 |
33.31 |
| 2026-04-15 12:00 |
09:52:53.11 |
+01:20:18.7 |
HIP 48591 |
34.64 |
| 2026-04-16 00:00 |
09:52:49.65 |
+01:21:18.8 |
HIP 48591 |
35.96 |