C/2019 H1 (NEOWISE)
| Parameter |
Value |
| Designation |
C/2019 H1 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-04-27T17:40:42.101760Z |
| Orbit solution date (soln_date, UTC) |
2022-06-20T23:12:33Z |
| Obs used |
165 |
| NEO |
- |
| M1 |
16.900 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-04-18T21:12:57.600000Z |
| Discovery magnitude (MPC) |
18.00 R |
| Discovery observatory (MPC) |
C51 · WISE |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-05-16.0000000 |
| e |
0.99219409 |
| q (au) |
1.844784 |
| a (au) |
236.331687 |
| i (deg) |
104.580185 |
| Ω (om, deg) |
269.186008 |
| ω (w, deg) |
19.282675 |
| M (ma, deg) |
0.004955 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.164 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.164 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.518 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
06:07:30.78 |
+40:37:10.5 |
HIP 28885 |
18.55 |
| 2026-02-03 12:00 |
06:07:23.94 |
+40:36:40.7 |
HIP 28885 |
17.41 |
| 2026-02-04 00:00 |
06:07:17.16 |
+40:36:10.7 |
HIP 28885 |
16.33 |
| 2026-02-04 12:00 |
06:07:10.44 |
+40:35:40.5 |
HIP 28885 |
15.31 |
| 2026-02-05 00:00 |
06:07:03.78 |
+40:35:10.1 |
HIP 28885 |
14.35 |
| 2026-02-05 12:00 |
06:06:57.19 |
+40:34:39.5 |
HIP 28885 |
13.48 |
| 2026-02-06 00:00 |
06:06:50.66 |
+40:34:08.7 |
HIP 28885 |
12.70 |
| 2026-02-06 12:00 |
06:06:44.19 |
+40:33:37.7 |
HIP 28885 |
12.04 |
| 2026-02-07 00:00 |
06:06:37.78 |
+40:33:06.6 |
HIP 28885 |
11.50 |
| 2026-02-07 12:00 |
06:06:31.44 |
+40:32:35.2 |
HIP 28885 |
11.10 |
| 2026-02-08 00:00 |
06:06:25.16 |
+40:32:03.7 |
HIP 28885 |
10.85 |
| 2026-02-08 12:00 |
06:06:18.95 |
+40:31:32.0 |
HIP 28885 |
10.77 |
| 2026-02-09 00:00 |
06:06:12.80 |
+40:31:00.2 |
HIP 28885 |
10.85 |
| 2026-02-09 12:00 |
06:06:06.72 |
+40:30:28.1 |
HIP 28885 |
11.08 |
| 2026-02-10 00:00 |
06:06:00.71 |
+40:29:56.0 |
HIP 28885 |
11.45 |
| 2026-02-10 12:00 |
06:05:54.76 |
+40:29:23.6 |
HIP 28885 |
11.95 |
| 2026-02-11 00:00 |
06:05:48.87 |
+40:28:51.1 |
HIP 28885 |
12.55 |
| 2026-02-11 12:00 |
06:05:43.06 |
+40:28:18.4 |
HIP 28885 |
13.25 |
| 2026-02-12 00:00 |
06:05:37.31 |
+40:27:45.6 |
HIP 28885 |
14.01 |
| 2026-02-12 12:00 |
06:05:31.63 |
+40:27:12.6 |
HIP 28885 |
14.84 |
| 2026-02-13 00:00 |
06:05:26.02 |
+40:26:39.5 |
HIP 28885 |
15.71 |
| 2026-02-13 12:00 |
06:05:20.48 |
+40:26:06.2 |
HIP 28885 |
16.62 |
| 2026-02-14 00:00 |
06:05:15.01 |
+40:25:32.8 |
HIP 28885 |
17.57 |
| 2026-02-14 12:00 |
06:05:09.60 |
+40:24:59.3 |
HIP 28885 |
18.53 |
| 2026-02-15 00:00 |
06:05:04.27 |
+40:24:25.6 |
HIP 28885 |
19.51 |
| 2026-02-15 12:00 |
06:04:59.01 |
+40:23:51.7 |
HIP 28885 |
20.51 |
| 2026-02-16 00:00 |
06:04:53.81 |
+40:23:17.8 |
HIP 28885 |
21.52 |
| 2026-02-16 12:00 |
06:04:48.69 |
+40:22:43.7 |
HIP 28885 |
22.53 |
| 2026-02-17 00:00 |
06:04:43.64 |
+40:22:09.5 |
HIP 28712 |
22.09 |
| 2026-02-17 12:00 |
06:04:38.66 |
+40:21:35.1 |
HIP 28712 |
21.15 |
| 2026-02-18 00:00 |
06:04:33.75 |
+40:21:00.7 |
HIP 28712 |
20.24 |
| 2026-02-18 12:00 |
06:04:28.92 |
+40:20:26.1 |
HIP 28712 |
19.34 |
| 2026-02-19 00:00 |
06:04:24.15 |
+40:19:51.4 |
HIP 28712 |
18.48 |
| 2026-02-19 12:00 |
06:04:19.46 |
+40:19:16.6 |
HIP 28712 |
17.63 |
| 2026-02-20 00:00 |
06:04:14.84 |
+40:18:41.7 |
HIP 28712 |
16.82 |
| 2026-02-20 12:00 |
06:04:10.29 |
+40:18:06.7 |
HIP 28712 |
16.03 |
| 2026-02-21 00:00 |
06:04:05.82 |
+40:17:31.6 |
HIP 28712 |
15.28 |
| 2026-02-21 12:00 |
06:04:01.42 |
+40:16:56.4 |
HIP 28712 |
14.56 |
| 2026-02-22 00:00 |
06:03:57.10 |
+40:16:21.1 |
HIP 28712 |
13.88 |
| 2026-02-22 12:00 |
06:03:52.84 |
+40:15:45.7 |
HIP 28712 |
13.24 |
| 2026-02-23 00:00 |
06:03:48.66 |
+40:15:10.2 |
HIP 28712 |
12.65 |
| 2026-02-23 12:00 |
06:03:44.56 |
+40:14:34.6 |
HIP 28712 |
12.11 |
| 2026-02-24 00:00 |
06:03:40.53 |
+40:13:58.9 |
HIP 28712 |
11.62 |