| Parameter |
Value |
| Designation |
C/2019 D1 (Flewelling) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-05-11T20:12:52.110720Z |
| Orbit solution date (soln_date, UTC) |
2022-07-19T01:12:15Z |
| Obs used |
797 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
15.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-02-26T15:28:50.505600Z |
| Discovery magnitude (MPC) |
16.75 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-06-19.0000000 |
| e |
0.98854927 |
| q (au) |
1.577555 |
| a (au) |
137.768888 |
| i (deg) |
34.098372 |
| Ω (om, deg) |
231.717805 |
| ω (w, deg) |
70.477432 |
| M (ma, deg) |
0.023257 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.316 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.316 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.999 |
| 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 |
| 2019-02-26 |
2019-05-11 |
+2.3057 |
-1.095 |
| 2019-05-12 |
2019-07-27 |
+16.0845 |
-3.717 |
| 2019-07-27 |
2019-12-04 |
-2.5143 |
+1.033 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
05:33:02.02 |
+03:58:37.5 |
HIP 26126 |
22.51 |
| 2026-05-12 12:00 |
05:33:07.58 |
+03:58:53.0 |
HIP 26126 |
21.53 |
| 2026-05-13 00:00 |
05:33:13.16 |
+03:59:08.3 |
HIP 26126 |
20.59 |
| 2026-05-13 12:00 |
05:33:18.77 |
+03:59:23.4 |
HIP 26126 |
19.71 |
| 2026-05-14 00:00 |
05:33:24.39 |
+03:59:38.3 |
HIP 26126 |
18.88 |
| 2026-05-14 12:00 |
05:33:30.05 |
+03:59:53.0 |
HIP 26126 |
18.12 |
| 2026-05-15 00:00 |
05:33:35.72 |
+04:00:07.5 |
HIP 26126 |
17.44 |
| 2026-05-15 12:00 |
05:33:41.41 |
+04:00:21.7 |
HIP 26126 |
16.84 |
| 2026-05-16 00:00 |
05:33:47.13 |
+04:00:35.8 |
HIP 26126 |
16.35 |
| 2026-05-16 12:00 |
05:33:52.87 |
+04:00:49.6 |
HIP 26126 |
15.97 |
| 2026-05-17 00:00 |
05:33:58.63 |
+04:01:03.2 |
HIP 26126 |
15.70 |
| 2026-05-17 12:00 |
05:34:04.41 |
+04:01:16.6 |
HIP 26126 |
15.57 |
| 2026-05-18 00:00 |
05:34:10.21 |
+04:01:29.7 |
HIP 26126 |
15.57 |
| 2026-05-18 12:00 |
05:34:16.03 |
+04:01:42.7 |
HIP 26126 |
15.70 |
| 2026-05-19 00:00 |
05:34:21.87 |
+04:01:55.4 |
HIP 26126 |
15.96 |
| 2026-05-19 12:00 |
05:34:27.72 |
+04:02:07.9 |
HIP 26126 |
16.35 |
| 2026-05-20 00:00 |
05:34:33.60 |
+04:02:20.2 |
HIP 26126 |
16.85 |
| 2026-05-20 12:00 |
05:34:39.49 |
+04:02:32.3 |
HIP 26126 |
17.47 |
| 2026-05-21 00:00 |
05:34:45.41 |
+04:02:44.1 |
HIP 26126 |
18.18 |
| 2026-05-21 12:00 |
05:34:51.33 |
+04:02:55.7 |
HIP 26126 |
18.98 |
| 2026-05-22 00:00 |
05:34:57.28 |
+04:03:07.1 |
HIP 26126 |
19.86 |
| 2026-05-22 12:00 |
05:35:03.24 |
+04:03:18.2 |
HIP 26126 |
20.81 |
| 2026-05-23 00:00 |
05:35:09.22 |
+04:03:29.2 |
HIP 26126 |
21.82 |
| 2026-05-23 12:00 |
05:35:15.22 |
+04:03:39.9 |
HIP 26126 |
22.89 |
| 2026-05-24 00:00 |
05:35:21.23 |
+04:03:50.3 |
HIP 26126 |
24.00 |
| 2026-05-24 12:00 |
05:35:27.25 |
+04:04:00.6 |
HIP 26126 |
25.15 |
| 2026-05-25 00:00 |
05:35:33.29 |
+04:04:10.6 |
HIP 26126 |
26.34 |
| 2026-05-25 12:00 |
05:35:39.35 |
+04:04:20.4 |
HIP 26126 |
27.56 |
| 2026-05-26 00:00 |
05:35:45.42 |
+04:04:30.0 |
HIP 26126 |
28.81 |
| 2026-05-26 12:00 |
05:35:51.50 |
+04:04:39.3 |
HIP 26126 |
30.09 |
| 2026-05-27 00:00 |
05:35:57.59 |
+04:04:48.4 |
HIP 26126 |
31.39 |
| 2026-05-27 12:00 |
05:36:03.70 |
+04:04:57.2 |
HIP 26126 |
32.71 |
| 2026-05-28 00:00 |
05:36:09.83 |
+04:05:05.9 |
HIP 26126 |
34.04 |
| 2026-05-28 12:00 |
05:36:15.96 |
+04:05:14.3 |
HIP 26522 |
33.85 |
| 2026-05-29 00:00 |
05:36:22.11 |
+04:05:22.4 |
HIP 26522 |
32.34 |
| 2026-05-29 12:00 |
05:36:28.26 |
+04:05:30.4 |
HIP 26522 |
30.84 |
| 2026-05-30 00:00 |
05:36:34.43 |
+04:05:38.1 |
HIP 26522 |
29.33 |
| 2026-05-30 12:00 |
05:36:40.61 |
+04:05:45.6 |
HIP 26522 |
27.83 |
| 2026-05-31 00:00 |
05:36:46.80 |
+04:05:52.8 |
HIP 26522 |
26.33 |
| 2026-05-31 12:00 |
05:36:53.00 |
+04:05:59.8 |
HIP 26522 |
24.84 |
| 2026-06-01 00:00 |
05:36:59.21 |
+04:06:06.6 |
HIP 26522 |
23.36 |
| 2026-06-01 12:00 |
05:37:05.44 |
+04:06:13.1 |
HIP 26522 |
21.88 |
| 2026-06-02 00:00 |
05:37:11.67 |
+04:06:19.4 |
HIP 26522 |
20.41 |