| 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) |
| 2026-06-01 00:00 |
09:53:30.14 |
+02:22:21.1 |
HIP 48503 |
18.91 |
| 2026-06-01 12:00 |
09:53:34.31 |
+02:22:38.2 |
HIP 48503 |
19.25 |
| 2026-06-02 00:00 |
09:53:38.55 |
+02:22:54.8 |
HIP 48503 |
19.64 |
| 2026-06-02 12:00 |
09:53:42.87 |
+02:23:11.0 |
HIP 48503 |
20.07 |
| 2026-06-03 00:00 |
09:53:47.26 |
+02:23:26.6 |
HIP 48503 |
20.55 |
| 2026-06-03 12:00 |
09:53:51.72 |
+02:23:41.7 |
HIP 48503 |
21.07 |
| 2026-06-04 00:00 |
09:53:56.25 |
+02:23:56.3 |
HIP 48503 |
21.64 |
| 2026-06-04 12:00 |
09:54:00.85 |
+02:24:10.5 |
HIP 48503 |
22.26 |
| 2026-06-05 00:00 |
09:54:05.52 |
+02:24:24.1 |
HIP 48503 |
22.92 |
| 2026-06-05 12:00 |
09:54:10.26 |
+02:24:37.2 |
HIP 48503 |
23.62 |
| 2026-06-06 00:00 |
09:54:15.07 |
+02:24:49.8 |
HIP 48503 |
24.36 |
| 2026-06-06 12:00 |
09:54:19.96 |
+02:25:01.9 |
HIP 48503 |
25.14 |
| 2026-06-07 00:00 |
09:54:24.91 |
+02:25:13.5 |
HIP 48503 |
25.96 |
| 2026-06-07 12:00 |
09:54:29.93 |
+02:25:24.6 |
HIP 48503 |
26.81 |
| 2026-06-08 00:00 |
09:54:35.01 |
+02:25:35.2 |
HIP 48503 |
27.70 |
| 2026-06-08 12:00 |
09:54:40.17 |
+02:25:45.3 |
HIP 48503 |
28.62 |
| 2026-06-09 00:00 |
09:54:45.39 |
+02:25:55.0 |
HIP 48704 |
28.77 |
| 2026-06-09 12:00 |
09:54:50.69 |
+02:26:04.1 |
HIP 48704 |
27.82 |
| 2026-06-10 00:00 |
09:54:56.04 |
+02:26:12.7 |
HIP 48704 |
26.90 |
| 2026-06-10 12:00 |
09:55:01.47 |
+02:26:20.8 |
HIP 48704 |
26.01 |
| 2026-06-11 00:00 |
09:55:06.96 |
+02:26:28.4 |
HIP 48704 |
25.16 |
| 2026-06-11 12:00 |
09:55:12.52 |
+02:26:35.5 |
HIP 48704 |
24.36 |
| 2026-06-12 00:00 |
09:55:18.14 |
+02:26:42.1 |
HIP 48704 |
23.61 |
| 2026-06-12 12:00 |
09:55:23.83 |
+02:26:48.2 |
HIP 48704 |
22.93 |
| 2026-06-13 00:00 |
09:55:29.59 |
+02:26:53.9 |
HIP 48704 |
22.32 |
| 2026-06-13 12:00 |
09:55:35.41 |
+02:26:59.0 |
HIP 48704 |
21.80 |
| 2026-06-14 00:00 |
09:55:41.29 |
+02:27:03.6 |
HIP 48704 |
21.36 |
| 2026-06-14 12:00 |
09:55:47.24 |
+02:27:07.8 |
HIP 48704 |
21.02 |
| 2026-06-15 00:00 |
09:55:53.25 |
+02:27:11.4 |
HIP 48704 |
20.80 |
| 2026-06-15 12:00 |
09:55:59.33 |
+02:27:14.6 |
HIP 48704 |
20.68 |
| 2026-06-16 00:00 |
09:56:05.46 |
+02:27:17.2 |
HIP 48704 |
20.69 |
| 2026-06-16 12:00 |
09:56:11.66 |
+02:27:19.4 |
HIP 48704 |
20.82 |
| 2026-06-17 00:00 |
09:56:17.92 |
+02:27:21.1 |
HIP 48704 |
21.08 |
| 2026-06-17 12:00 |
09:56:24.25 |
+02:27:22.2 |
HIP 48704 |
21.46 |
| 2026-06-18 00:00 |
09:56:30.63 |
+02:27:23.0 |
HIP 48704 |
21.96 |
| 2026-06-18 12:00 |
09:56:37.07 |
+02:27:23.2 |
HIP 48704 |
22.57 |
| 2026-06-19 00:00 |
09:56:43.58 |
+02:27:22.9 |
HIP 48704 |
23.30 |
| 2026-06-19 12:00 |
09:56:50.14 |
+02:27:22.2 |
HIP 48815 |
22.84 |
| 2026-06-20 00:00 |
09:56:56.76 |
+02:27:20.9 |
HIP 48815 |
22.21 |
| 2026-06-20 12:00 |
09:57:03.44 |
+02:27:19.2 |
HIP 48815 |
21.68 |
| 2026-06-21 00:00 |
09:57:10.18 |
+02:27:17.0 |
HIP 48815 |
21.26 |
| 2026-06-21 12:00 |
09:57:16.98 |
+02:27:14.4 |
HIP 48815 |
20.96 |
| 2026-06-22 00:00 |
09:57:23.83 |
+02:27:11.2 |
HIP 48815 |
20.78 |