C/2017 Y1 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2017 Y1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-08-31T11:16:29.493120Z |
| Orbit solution date (soln_date, UTC) |
2022-07-06T03:12:22Z |
| Obs used |
92 |
| NEO |
- |
| M1 |
9.300 |
| K1 |
13.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-03-09.0000000 |
| e |
0.99901916 |
| q (au) |
3.718608 |
| a (au) |
3791.251402 |
| i (deg) |
55.240118 |
| Ω (om, deg) |
307.509679 |
| ω (w, deg) |
134.447483 |
| M (ma, deg) |
0.000800 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.514 + 4.991\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.514 |
| n |
4.991 |
| gf |
0.935 |
| gb |
-0.899 |
| k |
0.999 |
| δ90 |
5.121 |
| 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) |
| 2026-02-03 00:00 |
11:33:19.89 |
-60:39:22.8 |
HIP 56249 |
11.39 |
| 2026-02-03 12:00 |
11:33:12.17 |
-60:40:09.3 |
HIP 56249 |
10.32 |
| 2026-02-04 00:00 |
11:33:04.37 |
-60:40:55.1 |
HIP 56249 |
9.29 |
| 2026-02-04 12:00 |
11:32:56.50 |
-60:41:40.4 |
HIP 56249 |
8.30 |
| 2026-02-05 00:00 |
11:32:48.57 |
-60:42:24.9 |
HIP 56249 |
7.37 |
| 2026-02-05 12:00 |
11:32:40.57 |
-60:43:08.8 |
HIP 56249 |
6.53 |
| 2026-02-06 00:00 |
11:32:32.51 |
-60:43:52.0 |
HIP 56249 |
5.81 |
| 2026-02-06 12:00 |
11:32:24.38 |
-60:44:34.6 |
HIP 56249 |
5.28 |
| 2026-02-07 00:00 |
11:32:16.18 |
-60:45:16.5 |
HIP 56249 |
4.97 |
| 2026-02-07 12:00 |
11:32:07.93 |
-60:45:57.7 |
HIP 56249 |
4.95 |
| 2026-02-08 00:00 |
11:31:59.61 |
-60:46:38.2 |
HIP 56281 |
5.02 |
| 2026-02-08 12:00 |
11:31:51.22 |
-60:47:18.1 |
HIP 56281 |
4.99 |
| 2026-02-09 00:00 |
11:31:42.78 |
-60:47:57.3 |
HIP 56281 |
5.27 |
| 2026-02-09 12:00 |
11:31:34.27 |
-60:48:35.8 |
HIP 56281 |
5.80 |
| 2026-02-10 00:00 |
11:31:25.71 |
-60:49:13.5 |
HIP 56281 |
6.53 |
| 2026-02-10 12:00 |
11:31:17.08 |
-60:49:50.6 |
HIP 56281 |
7.40 |
| 2026-02-11 00:00 |
11:31:08.40 |
-60:50:27.0 |
HIP 56281 |
8.37 |
| 2026-02-11 12:00 |
11:30:59.66 |
-60:51:02.7 |
HIP 56281 |
9.40 |
| 2026-02-12 00:00 |
11:30:50.87 |
-60:51:37.7 |
HIP 56281 |
10.47 |
| 2026-02-12 12:00 |
11:30:42.01 |
-60:52:12.0 |
HIP 56281 |
11.58 |
| 2026-02-13 00:00 |
11:30:33.11 |
-60:52:45.5 |
HIP 56162 |
12.05 |
| 2026-02-13 12:00 |
11:30:24.15 |
-60:53:18.4 |
HIP 56162 |
11.71 |
| 2026-02-14 00:00 |
11:30:15.14 |
-60:53:50.5 |
HIP 56162 |
11.50 |
| 2026-02-14 12:00 |
11:30:06.07 |
-60:54:21.9 |
HIP 56162 |
11.43 |
| 2026-02-15 00:00 |
11:29:56.95 |
-60:54:52.6 |
HIP 56162 |
11.50 |
| 2026-02-15 12:00 |
11:29:47.79 |
-60:55:22.5 |
HIP 56162 |
11.71 |
| 2026-02-16 00:00 |
11:29:38.57 |
-60:55:51.7 |
HIP 56162 |
12.05 |
| 2026-02-16 12:00 |
11:29:29.31 |
-60:56:20.2 |
HIP 56162 |
12.52 |
| 2026-02-17 00:00 |
11:29:20.00 |
-60:56:48.0 |
HIP 56162 |
13.10 |
| 2026-02-17 12:00 |
11:29:10.64 |
-60:57:15.0 |
HIP 56162 |
13.77 |
| 2026-02-18 00:00 |
11:29:01.24 |
-60:57:41.3 |
HIP 56162 |
14.52 |
| 2026-02-18 12:00 |
11:28:51.80 |
-60:58:06.8 |
HIP 56162 |
15.34 |
| 2026-02-19 00:00 |
11:28:42.31 |
-60:58:31.6 |
HIP 56162 |
16.22 |
| 2026-02-19 12:00 |
11:28:32.78 |
-60:58:55.6 |
HIP 55831 |
16.29 |
| 2026-02-20 00:00 |
11:28:23.21 |
-60:59:18.9 |
HIP 55831 |
15.09 |
| 2026-02-20 12:00 |
11:28:13.59 |
-60:59:41.5 |
HIP 55831 |
13.90 |
| 2026-02-21 00:00 |
11:28:03.94 |
-61:00:03.3 |
HIP 55831 |
12.71 |
| 2026-02-21 12:00 |
11:27:54.26 |
-61:00:24.3 |
HIP 55831 |
11.54 |
| 2026-02-22 00:00 |
11:27:44.53 |
-61:00:44.6 |
HIP 55831 |
10.39 |
| 2026-02-22 12:00 |
11:27:34.77 |
-61:01:04.1 |
HIP 55831 |
9.25 |
| 2026-02-23 00:00 |
11:27:24.98 |
-61:01:22.9 |
HIP 55831 |
8.15 |
| 2026-02-23 12:00 |
11:27:15.15 |
-61:01:40.9 |
HIP 55831 |
7.10 |
| 2026-02-24 00:00 |
11:27:05.29 |
-61:01:58.2 |
HIP 55831 |
6.12 |