| 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 |
+16.0844 |
-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) |
| 2026-07-29 00:00 |
05:48:34.92 |
+03:51:45.0 |
HIP 27385 |
10.90 |
| 2026-07-29 12:00 |
05:48:39.92 |
+03:51:23.9 |
HIP 27385 |
12.12 |
| 2026-07-30 00:00 |
05:48:44.89 |
+03:51:02.6 |
HIP 27385 |
13.36 |
| 2026-07-30 12:00 |
05:48:49.83 |
+03:50:41.1 |
HIP 27482 |
12.61 |
| 2026-07-31 00:00 |
05:48:54.74 |
+03:50:19.4 |
HIP 27482 |
11.84 |
| 2026-07-31 12:00 |
05:48:59.61 |
+03:49:57.5 |
HIP 27482 |
11.16 |
| 2026-08-01 00:00 |
05:49:04.46 |
+03:49:35.4 |
HIP 27482 |
10.59 |
| 2026-08-01 12:00 |
05:49:09.28 |
+03:49:13.0 |
HIP 27482 |
10.14 |
| 2026-08-02 00:00 |
05:49:14.06 |
+03:48:50.5 |
HIP 27482 |
9.82 |
| 2026-08-02 12:00 |
05:49:18.81 |
+03:48:27.8 |
HIP 27482 |
9.66 |
| 2026-08-03 00:00 |
05:49:23.53 |
+03:48:04.9 |
HIP 27482 |
9.65 |
| 2026-08-03 12:00 |
05:49:28.22 |
+03:47:41.7 |
HIP 27482 |
9.79 |
| 2026-08-04 00:00 |
05:49:32.88 |
+03:47:18.4 |
HIP 27482 |
10.07 |
| 2026-08-04 12:00 |
05:49:37.50 |
+03:46:54.9 |
HIP 27482 |
10.48 |
| 2026-08-05 00:00 |
05:49:42.09 |
+03:46:31.1 |
HIP 27482 |
11.00 |
| 2026-08-05 12:00 |
05:49:46.65 |
+03:46:07.2 |
HIP 27482 |
11.62 |
| 2026-08-06 00:00 |
05:49:51.18 |
+03:45:43.1 |
HIP 27482 |
12.31 |
| 2026-08-06 12:00 |
05:49:55.66 |
+03:45:18.8 |
HIP 27482 |
13.07 |
| 2026-08-07 00:00 |
05:50:00.12 |
+03:44:54.3 |
HIP 27482 |
13.88 |
| 2026-08-07 12:00 |
05:50:04.54 |
+03:44:29.6 |
HIP 27482 |
14.73 |
| 2026-08-08 00:00 |
05:50:08.93 |
+03:44:04.7 |
HIP 27482 |
15.62 |
| 2026-08-08 12:00 |
05:50:13.28 |
+03:43:39.6 |
HIP 27482 |
16.53 |
| 2026-08-09 00:00 |
05:50:17.59 |
+03:43:14.3 |
HIP 27482 |
17.46 |
| 2026-08-09 12:00 |
05:50:21.87 |
+03:42:48.9 |
HIP 27667 |
16.85 |
| 2026-08-10 00:00 |
05:50:26.12 |
+03:42:23.2 |
HIP 27667 |
15.92 |
| 2026-08-10 12:00 |
05:50:30.32 |
+03:41:57.4 |
HIP 27667 |
15.04 |
| 2026-08-11 00:00 |
05:50:34.49 |
+03:41:31.4 |
HIP 27667 |
14.19 |
| 2026-08-11 12:00 |
05:50:38.63 |
+03:41:05.2 |
HIP 27667 |
13.40 |
| 2026-08-12 00:00 |
05:50:42.72 |
+03:40:38.8 |
HIP 27667 |
12.66 |
| 2026-08-12 12:00 |
05:50:46.78 |
+03:40:12.2 |
HIP 27667 |
12.00 |
| 2026-08-13 00:00 |
05:50:50.80 |
+03:39:45.5 |
HIP 27667 |
11.41 |
| 2026-08-13 12:00 |
05:50:54.79 |
+03:39:18.5 |
HIP 27667 |
10.91 |
| 2026-08-14 00:00 |
05:50:58.73 |
+03:38:51.5 |
HIP 27667 |
10.51 |
| 2026-08-14 12:00 |
05:51:02.63 |
+03:38:24.2 |
HIP 27667 |
10.21 |
| 2026-08-15 00:00 |
05:51:06.50 |
+03:37:56.7 |
HIP 27667 |
10.03 |
| 2026-08-15 12:00 |
05:51:10.33 |
+03:37:29.1 |
HIP 27667 |
9.97 |
| 2026-08-16 00:00 |
05:51:14.11 |
+03:37:01.3 |
HIP 27667 |
10.03 |
| 2026-08-16 12:00 |
05:51:17.86 |
+03:36:33.4 |
HIP 27667 |
10.20 |
| 2026-08-17 00:00 |
05:51:21.57 |
+03:36:05.3 |
HIP 27667 |
10.48 |
| 2026-08-17 12:00 |
05:51:25.24 |
+03:35:37.0 |
HIP 27667 |
10.85 |
| 2026-08-18 00:00 |
05:51:28.86 |
+03:35:08.6 |
HIP 27667 |
11.31 |
| 2026-08-18 12:00 |
05:51:32.45 |
+03:34:40.0 |
HIP 27667 |
11.84 |
| 2026-08-19 00:00 |
05:51:35.99 |
+03:34:11.2 |
HIP 27667 |
12.43 |