| 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
$$
M_a = (10.399 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.399 |
| 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) |
| 2026-03-26 00:00 |
15:52:39.67 |
-54:35:32.9 |
HIP 77913 |
17.91 |
| 2026-03-26 12:00 |
15:52:32.48 |
-54:35:58.0 |
HIP 77913 |
18.99 |
| 2026-03-27 00:00 |
15:52:25.21 |
-54:36:22.8 |
HIP 77913 |
20.08 |
| 2026-03-27 12:00 |
15:52:17.86 |
-54:36:47.2 |
HIP 77567 |
20.31 |
| 2026-03-28 00:00 |
15:52:10.44 |
-54:37:11.1 |
HIP 77567 |
19.17 |
| 2026-03-28 12:00 |
15:52:02.94 |
-54:37:34.7 |
HIP 77567 |
18.02 |
| 2026-03-29 00:00 |
15:51:55.36 |
-54:37:57.9 |
HIP 77567 |
16.87 |
| 2026-03-29 12:00 |
15:51:47.70 |
-54:38:20.6 |
HIP 77567 |
15.71 |
| 2026-03-30 00:00 |
15:51:39.97 |
-54:38:43.0 |
HIP 77567 |
14.55 |
| 2026-03-30 12:00 |
15:51:32.17 |
-54:39:04.9 |
HIP 77567 |
13.38 |
| 2026-03-31 00:00 |
15:51:24.28 |
-54:39:26.4 |
HIP 77567 |
12.22 |
| 2026-03-31 12:00 |
15:51:16.33 |
-54:39:47.5 |
HIP 77567 |
11.05 |
| 2026-04-01 00:00 |
15:51:08.30 |
-54:40:08.2 |
HIP 77567 |
9.89 |
| 2026-04-01 12:00 |
15:51:00.20 |
-54:40:28.5 |
HIP 77566 |
8.74 |
| 2026-04-02 00:00 |
15:50:52.03 |
-54:40:48.3 |
HIP 77566 |
7.59 |
| 2026-04-02 12:00 |
15:50:43.78 |
-54:41:07.7 |
HIP 77566 |
6.47 |
| 2026-04-03 00:00 |
15:50:35.47 |
-54:41:26.7 |
HIP 77566 |
5.39 |
| 2026-04-03 12:00 |
15:50:27.08 |
-54:41:45.2 |
HIP 77566 |
4.41 |
| 2026-04-04 00:00 |
15:50:18.62 |
-54:42:03.3 |
HIP 77566 |
3.59 |
| 2026-04-04 12:00 |
15:50:10.10 |
-54:42:20.9 |
HIP 77566 |
3.10 |
| 2026-04-05 00:00 |
15:50:01.50 |
-54:42:38.1 |
HIP 77566 |
3.10 |
| 2026-04-05 12:00 |
15:49:52.84 |
-54:42:54.8 |
HIP 77566 |
3.60 |
| 2026-04-06 00:00 |
15:49:44.11 |
-54:43:11.1 |
HIP 77566 |
4.43 |
| 2026-04-06 12:00 |
15:49:35.31 |
-54:43:26.9 |
HIP 77566 |
5.46 |
| 2026-04-07 00:00 |
15:49:26.44 |
-54:43:42.3 |
HIP 77566 |
6.59 |
| 2026-04-07 12:00 |
15:49:17.51 |
-54:43:57.2 |
HIP 77566 |
7.79 |
| 2026-04-08 00:00 |
15:49:08.51 |
-54:44:11.6 |
HIP 77566 |
9.03 |
| 2026-04-08 12:00 |
15:48:59.45 |
-54:44:25.6 |
HIP 77566 |
10.30 |
| 2026-04-09 00:00 |
15:48:50.32 |
-54:44:39.1 |
HIP 77566 |
11.59 |
| 2026-04-09 12:00 |
15:48:41.13 |
-54:44:52.1 |
HIP 77566 |
12.90 |
| 2026-04-10 00:00 |
15:48:31.88 |
-54:45:04.7 |
HIP 77566 |
14.23 |
| 2026-04-10 12:00 |
15:48:22.57 |
-54:45:16.8 |
HIP 77566 |
15.57 |
| 2026-04-11 00:00 |
15:48:13.19 |
-54:45:28.4 |
HIP 77566 |
16.92 |
| 2026-04-11 12:00 |
15:48:03.76 |
-54:45:39.5 |
HIP 77566 |
18.28 |
| 2026-04-12 00:00 |
15:47:54.26 |
-54:45:50.1 |
HIP 77566 |
19.65 |
| 2026-04-12 12:00 |
15:47:44.70 |
-54:46:00.2 |
HIP 77566 |
21.03 |
| 2026-04-13 00:00 |
15:47:35.09 |
-54:46:09.8 |
HIP 77566 |
22.42 |
| 2026-04-13 12:00 |
15:47:25.42 |
-54:46:19.0 |
HIP 77566 |
23.82 |
| 2026-04-14 00:00 |
15:47:15.69 |
-54:46:27.6 |
HIP 77566 |
25.23 |
| 2026-04-14 12:00 |
15:47:05.90 |
-54:46:35.7 |
HIP 77566 |
26.65 |
| 2026-04-15 00:00 |
15:46:56.06 |
-54:46:43.4 |
HIP 77117 |
26.67 |
| 2026-04-15 12:00 |
15:46:46.17 |
-54:46:50.5 |
HIP 77117 |
25.63 |
| 2026-04-16 00:00 |
15:46:36.22 |
-54:46:57.1 |
HIP 77117 |
24.62 |