| 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) |
| 2026-03-26 00:00 |
13:33:00.40 |
-10:57:05.4 |
HIP 66018 |
22.82 |
| 2026-03-26 12:00 |
13:32:42.34 |
-10:55:37.5 |
HIP 66018 |
21.80 |
| 2026-03-27 00:00 |
13:32:24.17 |
-10:54:08.8 |
HIP 66018 |
21.75 |
| 2026-03-27 12:00 |
13:32:05.89 |
-10:52:39.3 |
HIP 66018 |
22.72 |
| 2026-03-28 00:00 |
13:31:47.51 |
-10:51:09.1 |
HIP 66018 |
24.58 |
| 2026-03-28 12:00 |
13:31:29.02 |
-10:49:38.2 |
HIP 66018 |
27.18 |
| 2026-03-29 00:00 |
13:31:10.44 |
-10:48:06.6 |
HIP 65821 |
23.83 |
| 2026-03-29 12:00 |
13:30:51.76 |
-10:46:34.3 |
HIP 65821 |
19.02 |
| 2026-03-30 00:00 |
13:30:32.98 |
-10:45:01.3 |
HIP 65821 |
14.20 |
| 2026-03-30 12:00 |
13:30:14.11 |
-10:43:27.7 |
HIP 65821 |
9.41 |
| 2026-03-31 00:00 |
13:29:55.16 |
-10:41:53.4 |
HIP 65821 |
4.80 |
| 2026-03-31 12:00 |
13:29:36.11 |
-10:40:18.4 |
HIP 65821 |
2.41 |
| 2026-04-01 00:00 |
13:29:16.98 |
-10:38:42.8 |
HIP 65821 |
6.14 |
| 2026-04-01 12:00 |
13:28:57.77 |
-10:37:06.6 |
HIP 65821 |
10.92 |
| 2026-04-02 00:00 |
13:28:38.49 |
-10:35:29.8 |
HIP 65821 |
15.85 |
| 2026-04-02 12:00 |
13:28:19.12 |
-10:33:52.4 |
HIP 65801 |
18.27 |
| 2026-04-03 00:00 |
13:27:59.68 |
-10:32:14.4 |
HIP 65801 |
21.46 |
| 2026-04-03 12:00 |
13:27:40.17 |
-10:30:35.8 |
HIP 65801 |
25.28 |
| 2026-04-04 00:00 |
13:27:20.60 |
-10:28:56.7 |
HIP 65801 |
29.49 |
| 2026-04-04 12:00 |
13:27:00.95 |
-10:27:17.1 |
HIP 65801 |
33.96 |
| 2026-04-05 00:00 |
13:26:41.25 |
-10:25:36.9 |
HIP 65801 |
38.60 |
| 2026-04-05 12:00 |
13:26:21.49 |
-10:23:56.2 |
HIP 65412 |
33.88 |
| 2026-04-06 00:00 |
13:26:01.66 |
-10:22:15.1 |
HIP 65412 |
28.88 |
| 2026-04-06 12:00 |
13:25:41.79 |
-10:20:33.4 |
HIP 65412 |
23.94 |
| 2026-04-07 00:00 |
13:25:21.86 |
-10:18:51.3 |
HIP 65412 |
19.10 |
| 2026-04-07 12:00 |
13:25:01.89 |
-10:17:08.7 |
HIP 65412 |
14.50 |
| 2026-04-08 00:00 |
13:24:41.87 |
-10:15:25.7 |
HIP 65412 |
10.46 |
| 2026-04-08 12:00 |
13:24:21.80 |
-10:13:42.3 |
HIP 65412 |
7.93 |
| 2026-04-09 00:00 |
13:24:01.70 |
-10:11:58.5 |
HIP 65412 |
8.44 |
| 2026-04-09 12:00 |
13:23:41.56 |
-10:10:14.3 |
HIP 65412 |
11.60 |
| 2026-04-10 00:00 |
13:23:21.39 |
-10:08:29.8 |
HIP 65412 |
15.91 |
| 2026-04-10 12:00 |
13:23:01.18 |
-10:06:44.9 |
HIP 65412 |
20.68 |
| 2026-04-11 00:00 |
13:22:40.95 |
-10:04:59.6 |
HIP 65163 |
22.40 |
| 2026-04-11 12:00 |
13:22:20.70 |
-10:03:14.0 |
HIP 65163 |
17.15 |
| 2026-04-12 00:00 |
13:22:00.42 |
-10:01:28.2 |
HIP 65163 |
11.94 |
| 2026-04-12 12:00 |
13:21:40.13 |
-09:59:42.0 |
HIP 65163 |
6.85 |
| 2026-04-13 00:00 |
13:21:19.82 |
-09:57:55.6 |
HIP 65163 |
2.74 |
| 2026-04-13 12:00 |
13:20:59.49 |
-09:56:08.9 |
HIP 65163 |
4.94 |
| 2026-04-14 00:00 |
13:20:39.16 |
-09:54:22.0 |
HIP 65163 |
9.89 |
| 2026-04-14 12:00 |
13:20:18.82 |
-09:52:34.9 |
HIP 65163 |
15.09 |
| 2026-04-15 00:00 |
13:19:58.48 |
-09:50:47.6 |
HIP 65163 |
20.36 |
| 2026-04-15 12:00 |
13:19:38.15 |
-09:49:00.2 |
HIP 64911 |
24.38 |
| 2026-04-16 00:00 |
13:19:17.81 |
-09:47:12.5 |
HIP 64911 |
19.33 |