| Parameter |
Value |
| Designation |
15P/Finlay |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2014-12-27T01:44:35.957760Z |
| Orbit solution date (soln_date, UTC) |
2024-04-16T11:19:30Z |
| Obs used |
1655 |
| NEO |
Yes |
| M1 |
14.900 |
| K1 |
8.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-11-01.0000000 |
| e |
0.72018544 |
| q (au) |
0.976687 |
| a (au) |
3.490479 |
| i (deg) |
6.800480 |
| Ω (om, deg) |
13.753875 |
| ω (w, deg) |
347.625750 |
| M (ma, deg) |
46.690962 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.416 + 5.627\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.416 |
| n |
5.627 |
| gf |
1.000 |
| gb |
-0.643 |
| k |
0.800 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2021-04-10 |
2022-03-03 |
+4.0180 |
-1.591 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
13:02:59.63 |
-08:17:54.3 |
HIP 63685 |
22.48 |
| 2026-05-12 12:00 |
13:02:43.59 |
-08:16:23.8 |
HIP 63685 |
21.54 |
| 2026-05-13 00:00 |
13:02:27.70 |
-08:14:54.1 |
HIP 63548 |
20.36 |
| 2026-05-13 12:00 |
13:02:11.96 |
-08:13:25.1 |
HIP 63548 |
18.31 |
| 2026-05-14 00:00 |
13:01:56.36 |
-08:11:57.0 |
HIP 63548 |
17.06 |
| 2026-05-14 12:00 |
13:01:40.92 |
-08:10:29.6 |
HIP 63548 |
16.75 |
| 2026-05-15 00:00 |
13:01:25.63 |
-08:09:03.1 |
HIP 63548 |
17.42 |
| 2026-05-15 12:00 |
13:01:10.50 |
-08:07:37.3 |
HIP 63548 |
18.92 |
| 2026-05-16 00:00 |
13:00:55.52 |
-08:06:12.4 |
HIP 63548 |
21.07 |
| 2026-05-16 12:00 |
13:00:40.70 |
-08:04:48.4 |
HIP 63548 |
23.66 |
| 2026-05-17 00:00 |
13:00:26.05 |
-08:03:25.2 |
HIP 63548 |
26.55 |
| 2026-05-17 12:00 |
13:00:11.56 |
-08:02:02.9 |
HIP 63548 |
29.63 |
| 2026-05-18 00:00 |
12:59:57.23 |
-08:00:41.5 |
HIP 63548 |
32.84 |
| 2026-05-18 12:00 |
12:59:43.07 |
-07:59:21.0 |
HIP 63548 |
36.12 |
| 2026-05-19 00:00 |
12:59:29.08 |
-07:58:01.5 |
HIP 63548 |
39.44 |
| 2026-05-19 12:00 |
12:59:15.25 |
-07:56:42.8 |
HIP 63548 |
42.79 |
| 2026-05-20 00:00 |
12:59:01.60 |
-07:55:25.1 |
HIP 63548 |
46.15 |
| 2026-05-20 12:00 |
12:58:48.12 |
-07:54:08.3 |
HIP 63270 |
47.54 |
| 2026-05-21 00:00 |
12:58:34.81 |
-07:52:52.5 |
HIP 63270 |
45.50 |
| 2026-05-21 12:00 |
12:58:21.68 |
-07:51:37.6 |
HIP 63270 |
43.67 |
| 2026-05-22 00:00 |
12:58:08.72 |
-07:50:23.7 |
HIP 63270 |
42.08 |
| 2026-05-22 12:00 |
12:57:55.94 |
-07:49:10.9 |
HIP 63270 |
40.72 |
| 2026-05-23 00:00 |
12:57:43.34 |
-07:47:59.0 |
HIP 63270 |
39.63 |
| 2026-05-23 12:00 |
12:57:30.92 |
-07:46:48.1 |
HIP 63270 |
38.81 |
| 2026-05-24 00:00 |
12:57:18.68 |
-07:45:38.2 |
HIP 63270 |
38.25 |
| 2026-05-24 12:00 |
12:57:06.62 |
-07:44:29.3 |
HIP 63270 |
37.97 |
| 2026-05-25 00:00 |
12:56:54.74 |
-07:43:21.5 |
HIP 62991 |
37.25 |
| 2026-05-25 12:00 |
12:56:43.05 |
-07:42:14.7 |
HIP 62991 |
34.20 |
| 2026-05-26 00:00 |
12:56:31.54 |
-07:41:08.9 |
HIP 62991 |
31.21 |
| 2026-05-26 12:00 |
12:56:20.21 |
-07:40:04.2 |
HIP 62991 |
28.29 |
| 2026-05-27 00:00 |
12:56:09.07 |
-07:39:00.5 |
HIP 62991 |
25.43 |
| 2026-05-27 12:00 |
12:55:58.12 |
-07:37:57.9 |
HIP 62991 |
22.64 |
| 2026-05-28 00:00 |
12:55:47.35 |
-07:36:56.4 |
HIP 62991 |
19.94 |
| 2026-05-28 12:00 |
12:55:36.77 |
-07:35:55.9 |
HIP 62991 |
17.33 |
| 2026-05-29 00:00 |
12:55:26.38 |
-07:34:56.5 |
HIP 62991 |
14.84 |
| 2026-05-29 12:00 |
12:55:16.18 |
-07:33:58.2 |
HIP 62991 |
12.50 |
| 2026-05-30 00:00 |
12:55:06.17 |
-07:33:01.0 |
HIP 62991 |
10.38 |
| 2026-05-30 12:00 |
12:54:56.35 |
-07:32:04.9 |
HIP 62991 |
8.60 |
| 2026-05-31 00:00 |
12:54:46.72 |
-07:31:09.9 |
HIP 62991 |
7.34 |
| 2026-05-31 12:00 |
12:54:37.28 |
-07:30:16.0 |
HIP 62991 |
6.86 |
| 2026-06-01 00:00 |
12:54:28.04 |
-07:29:23.2 |
HIP 62991 |
7.24 |
| 2026-06-01 12:00 |
12:54:18.99 |
-07:28:31.5 |
HIP 62991 |
8.33 |
| 2026-06-02 00:00 |
12:54:10.13 |
-07:27:41.0 |
HIP 62991 |
9.86 |