| Parameter |
Value |
| Designation |
19P/Borrelly |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-02-01T18:20:14.879040Z |
| Orbit solution date (soln_date, UTC) |
2024-12-30T09:03:27Z |
| Obs used |
2452 |
| NEO |
- |
| M1 |
9.800 |
| K1 |
14.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-03-06.0000000 |
| e |
0.63791428 |
| q (au) |
1.306030 |
| a (au) |
3.606965 |
| i (deg) |
29.318662 |
| Ω (om, deg) |
74.300843 |
| ω (w, deg) |
351.861606 |
| M (ma, deg) |
312.122920 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.210 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.210 |
| n |
6.000 |
| gf |
0.800 |
| gb |
-0.962 |
| k |
0.999 |
| 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 |
| 2021-02-02 |
2021-07-04 |
-78.0808 |
+33.211 |
| 2021-07-04 |
2022-02-01 |
+6.5636 |
-1.743 |
| 2022-02-01 |
2022-05-18 |
-2.2914 |
-0.440 |
| 2022-05-18 |
2024-05-02 |
+2.9727 |
-2.179 |
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 |
16:45:27.13 |
-27:13:44.7 |
HIP 81981 |
15.94 |
| 2026-07-29 12:00 |
16:45:16.36 |
-27:13:51.0 |
HIP 81981 |
14.74 |
| 2026-07-30 00:00 |
16:45:05.79 |
-27:13:57.3 |
HIP 81981 |
13.87 |
| 2026-07-30 12:00 |
16:44:55.43 |
-27:14:03.7 |
HIP 81981 |
13.36 |
| 2026-07-31 00:00 |
16:44:45.27 |
-27:14:10.2 |
HIP 81981 |
13.23 |
| 2026-07-31 12:00 |
16:44:35.32 |
-27:14:16.8 |
HIP 81981 |
13.48 |
| 2026-08-01 00:00 |
16:44:25.58 |
-27:14:23.5 |
HIP 81939 |
13.11 |
| 2026-08-01 12:00 |
16:44:16.04 |
-27:14:30.3 |
HIP 81939 |
12.87 |
| 2026-08-02 00:00 |
16:44:06.71 |
-27:14:37.3 |
HIP 81939 |
12.97 |
| 2026-08-02 12:00 |
16:43:57.59 |
-27:14:44.4 |
HIP 81939 |
13.38 |
| 2026-08-03 00:00 |
16:43:48.68 |
-27:14:51.6 |
HIP 81939 |
14.04 |
| 2026-08-03 12:00 |
16:43:39.97 |
-27:14:59.0 |
HIP 81821 |
12.36 |
| 2026-08-04 00:00 |
16:43:31.48 |
-27:15:06.5 |
HIP 81821 |
10.62 |
| 2026-08-04 12:00 |
16:43:23.20 |
-27:15:14.1 |
HIP 81821 |
8.98 |
| 2026-08-05 00:00 |
16:43:15.13 |
-27:15:21.9 |
HIP 81821 |
7.48 |
| 2026-08-05 12:00 |
16:43:07.27 |
-27:15:29.9 |
HIP 81821 |
6.19 |
| 2026-08-06 00:00 |
16:42:59.62 |
-27:15:38.0 |
HIP 81821 |
5.20 |
| 2026-08-06 12:00 |
16:42:52.18 |
-27:15:46.3 |
HIP 81821 |
4.66 |
| 2026-08-07 00:00 |
16:42:44.96 |
-27:15:54.8 |
HIP 81821 |
4.68 |
| 2026-08-07 12:00 |
16:42:37.95 |
-27:16:03.5 |
HIP 81821 |
5.20 |
| 2026-08-08 00:00 |
16:42:31.15 |
-27:16:12.3 |
HIP 81821 |
6.07 |
| 2026-08-08 12:00 |
16:42:24.57 |
-27:16:21.3 |
HIP 81821 |
7.13 |
| 2026-08-09 00:00 |
16:42:18.21 |
-27:16:30.5 |
HIP 81821 |
8.28 |
| 2026-08-09 12:00 |
16:42:12.05 |
-27:16:40.0 |
HIP 81821 |
9.46 |
| 2026-08-10 00:00 |
16:42:06.11 |
-27:16:49.6 |
HIP 81821 |
10.66 |
| 2026-08-10 12:00 |
16:42:00.39 |
-27:16:59.4 |
HIP 81747 |
10.93 |
| 2026-08-11 00:00 |
16:41:54.89 |
-27:17:09.5 |
HIP 81747 |
10.90 |
| 2026-08-11 12:00 |
16:41:49.60 |
-27:17:19.7 |
HIP 81747 |
11.01 |
| 2026-08-12 00:00 |
16:41:44.52 |
-27:17:30.2 |
HIP 81747 |
11.24 |
| 2026-08-12 12:00 |
16:41:39.66 |
-27:17:40.9 |
HIP 81747 |
11.58 |
| 2026-08-13 00:00 |
16:41:35.02 |
-27:17:51.8 |
HIP 81747 |
12.00 |
| 2026-08-13 12:00 |
16:41:30.59 |
-27:18:03.0 |
HIP 81747 |
12.48 |
| 2026-08-14 00:00 |
16:41:26.39 |
-27:18:14.3 |
HIP 81747 |
13.00 |
| 2026-08-14 12:00 |
16:41:22.39 |
-27:18:26.0 |
HIP 81747 |
13.55 |
| 2026-08-15 00:00 |
16:41:18.62 |
-27:18:37.8 |
HIP 81747 |
14.12 |
| 2026-08-15 12:00 |
16:41:15.05 |
-27:18:49.9 |
HIP 81747 |
14.70 |
| 2026-08-16 00:00 |
16:41:11.71 |
-27:19:02.3 |
HIP 81747 |
15.27 |
| 2026-08-16 12:00 |
16:41:08.58 |
-27:19:14.9 |
HIP 81747 |
15.84 |
| 2026-08-17 00:00 |
16:41:05.67 |
-27:19:27.8 |
HIP 81747 |
16.39 |
| 2026-08-17 12:00 |
16:41:02.97 |
-27:19:40.9 |
HIP 81747 |
16.93 |
| 2026-08-18 00:00 |
16:41:00.48 |
-27:19:54.3 |
HIP 81747 |
17.45 |
| 2026-08-18 12:00 |
16:40:58.22 |
-27:20:07.9 |
HIP 81747 |
17.94 |
| 2026-08-19 00:00 |
16:40:56.16 |
-27:20:21.8 |
HIP 81747 |
18.42 |