| Parameter |
Value |
| Designation |
C/2015 V1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-12-17T19:17:15.800640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:16Z |
| Obs used |
2145 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
8.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-06-28.0000000 |
| e |
1.00055464 |
| q (au) |
4.266704 |
| a (au) |
-7692.742203 |
| i (deg) |
139.230487 |
| Ω (om, deg) |
197.193756 |
| ω (w, deg) |
179.649665 |
| M (ma, deg) |
-0.000252 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.400 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.400 |
| n |
2.000 |
| gf |
0.821 |
| gb |
-0.500 |
| k |
0.901 |
| δ90 |
1.000 |
| 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 |
| 2015-11-02 |
2016-09-21 |
+10.7844 |
-8.539 |
| 2016-09-21 |
2017-03-03 |
+2.3776 |
-2.080 |
| 2017-03-03 |
2017-12-17 |
-9.8282 |
+6.267 |
| 2017-12-17 |
2019-06-11 |
+7.0878 |
-4.329 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
15:14:52.83 |
-52:28:43.8 |
HIP 74599 |
9.98 |
| 2026-07-29 12:00 |
15:14:49.57 |
-52:27:41.3 |
HIP 74599 |
10.83 |
| 2026-07-30 00:00 |
15:14:46.39 |
-52:26:39.0 |
HIP 74599 |
11.73 |
| 2026-07-30 12:00 |
15:14:43.30 |
-52:25:36.8 |
HIP 74599 |
12.67 |
| 2026-07-31 00:00 |
15:14:40.28 |
-52:24:34.6 |
HIP 74599 |
13.64 |
| 2026-07-31 12:00 |
15:14:37.35 |
-52:23:32.6 |
HIP 74599 |
14.64 |
| 2026-08-01 00:00 |
15:14:34.49 |
-52:22:30.7 |
HIP 74599 |
15.65 |
| 2026-08-01 12:00 |
15:14:31.72 |
-52:21:28.9 |
HIP 74599 |
16.67 |
| 2026-08-02 00:00 |
15:14:29.03 |
-52:20:27.2 |
HIP 74599 |
17.70 |
| 2026-08-02 12:00 |
15:14:26.42 |
-52:19:25.7 |
HIP 74599 |
18.74 |
| 2026-08-03 00:00 |
15:14:23.89 |
-52:18:24.3 |
HIP 74620 |
18.59 |
| 2026-08-03 12:00 |
15:14:21.44 |
-52:17:23.0 |
HIP 74620 |
17.67 |
| 2026-08-04 00:00 |
15:14:19.07 |
-52:16:21.8 |
HIP 74620 |
16.77 |
| 2026-08-04 12:00 |
15:14:16.78 |
-52:15:20.8 |
HIP 74620 |
15.89 |
| 2026-08-05 00:00 |
15:14:14.58 |
-52:14:19.9 |
HIP 74620 |
15.03 |
| 2026-08-05 12:00 |
15:14:12.45 |
-52:13:19.2 |
HIP 74620 |
14.20 |
| 2026-08-06 00:00 |
15:14:10.41 |
-52:12:18.6 |
HIP 74620 |
13.40 |
| 2026-08-06 12:00 |
15:14:08.44 |
-52:11:18.2 |
HIP 74620 |
12.64 |
| 2026-08-07 00:00 |
15:14:06.56 |
-52:10:18.0 |
HIP 74620 |
11.92 |
| 2026-08-07 12:00 |
15:14:04.76 |
-52:09:17.9 |
HIP 74620 |
11.24 |
| 2026-08-08 00:00 |
15:14:03.03 |
-52:08:18.0 |
HIP 74620 |
10.61 |
| 2026-08-08 12:00 |
15:14:01.39 |
-52:07:18.2 |
HIP 74620 |
10.04 |
| 2026-08-09 00:00 |
15:13:59.83 |
-52:06:18.6 |
HIP 74620 |
9.55 |
| 2026-08-09 12:00 |
15:13:58.35 |
-52:05:19.2 |
HIP 74620 |
9.13 |
| 2026-08-10 00:00 |
15:13:56.95 |
-52:04:20.0 |
HIP 74620 |
8.80 |
| 2026-08-10 12:00 |
15:13:55.62 |
-52:03:21.0 |
HIP 74620 |
8.57 |
| 2026-08-11 00:00 |
15:13:54.38 |
-52:02:22.1 |
HIP 74620 |
8.45 |
| 2026-08-11 12:00 |
15:13:53.22 |
-52:01:23.5 |
HIP 74620 |
8.42 |
| 2026-08-12 00:00 |
15:13:52.14 |
-52:00:25.1 |
HIP 74461 |
8.40 |
| 2026-08-12 12:00 |
15:13:51.14 |
-51:59:26.8 |
HIP 74461 |
8.07 |
| 2026-08-13 00:00 |
15:13:50.21 |
-51:58:28.8 |
HIP 74461 |
7.85 |
| 2026-08-13 12:00 |
15:13:49.37 |
-51:57:31.0 |
HIP 74461 |
7.77 |
| 2026-08-14 00:00 |
15:13:48.60 |
-51:56:33.3 |
HIP 74461 |
7.82 |
| 2026-08-14 12:00 |
15:13:47.92 |
-51:55:36.0 |
HIP 74461 |
8.00 |
| 2026-08-15 00:00 |
15:13:47.31 |
-51:54:38.8 |
HIP 74461 |
8.29 |
| 2026-08-15 12:00 |
15:13:46.78 |
-51:53:41.8 |
HIP 74461 |
8.69 |
| 2026-08-16 00:00 |
15:13:46.33 |
-51:52:45.1 |
HIP 74461 |
9.18 |
| 2026-08-16 12:00 |
15:13:45.96 |
-51:51:48.6 |
HIP 74461 |
9.74 |
| 2026-08-17 00:00 |
15:13:45.66 |
-51:50:52.4 |
HIP 74461 |
10.37 |
| 2026-08-17 12:00 |
15:13:45.44 |
-51:49:56.4 |
HIP 74461 |
11.04 |
| 2026-08-18 00:00 |
15:13:45.30 |
-51:49:00.6 |
HIP 74461 |
11.75 |
| 2026-08-18 12:00 |
15:13:45.24 |
-51:48:05.1 |
HIP 74461 |
12.49 |
| 2026-08-19 00:00 |
15:13:45.25 |
-51:47:09.8 |
HIP 74461 |
13.26 |