| Parameter |
Value |
| Designation |
C/1885 X2 (Barnard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1886-05-03T18:53:20.048640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:53Z |
| Obs used |
76 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1886-02-01.0000000 |
| e |
1.00020016 |
| q (au) |
0.479255 |
| a (au) |
-2394.381815 |
| i (deg) |
84.440812 |
| Ω (om, deg) |
69.909995 |
| ω (w, deg) |
119.624515 |
| M (ma, deg) |
-0.000772 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-07-29 00:00 |
04:50:08.48 |
-44:33:27.6 |
HIP 22546 |
19.89 |
| 2026-07-29 12:00 |
04:50:09.14 |
-44:33:35.6 |
HIP 22546 |
19.93 |
| 2026-07-30 00:00 |
04:50:09.78 |
-44:33:43.7 |
HIP 22546 |
19.98 |
| 2026-07-30 12:00 |
04:50:10.42 |
-44:33:51.8 |
HIP 22546 |
20.04 |
| 2026-07-31 00:00 |
04:50:11.06 |
-44:34:00.0 |
HIP 22546 |
20.10 |
| 2026-07-31 12:00 |
04:50:11.68 |
-44:34:08.2 |
HIP 22546 |
20.16 |
| 2026-08-01 00:00 |
04:50:12.30 |
-44:34:16.5 |
HIP 22546 |
20.22 |
| 2026-08-01 12:00 |
04:50:12.91 |
-44:34:24.8 |
HIP 22546 |
20.28 |
| 2026-08-02 00:00 |
04:50:13.51 |
-44:34:33.2 |
HIP 22546 |
20.35 |
| 2026-08-02 12:00 |
04:50:14.11 |
-44:34:41.6 |
HIP 22546 |
20.42 |
| 2026-08-03 00:00 |
04:50:14.70 |
-44:34:50.1 |
HIP 22546 |
20.50 |
| 2026-08-03 12:00 |
04:50:15.28 |
-44:34:58.7 |
HIP 22546 |
20.57 |
| 2026-08-04 00:00 |
04:50:15.86 |
-44:35:07.3 |
HIP 22546 |
20.65 |
| 2026-08-04 12:00 |
04:50:16.42 |
-44:35:16.0 |
HIP 22546 |
20.73 |
| 2026-08-05 00:00 |
04:50:16.98 |
-44:35:24.7 |
HIP 22546 |
20.82 |
| 2026-08-05 12:00 |
04:50:17.53 |
-44:35:33.4 |
HIP 22546 |
20.90 |
| 2026-08-06 00:00 |
04:50:18.08 |
-44:35:42.2 |
HIP 22546 |
20.99 |
| 2026-08-06 12:00 |
04:50:18.61 |
-44:35:51.1 |
HIP 22546 |
21.09 |
| 2026-08-07 00:00 |
04:50:19.14 |
-44:36:00.0 |
HIP 22537 |
21.04 |
| 2026-08-07 12:00 |
04:50:19.66 |
-44:36:09.0 |
HIP 22537 |
20.87 |
| 2026-08-08 00:00 |
04:50:20.17 |
-44:36:18.0 |
HIP 22537 |
20.70 |
| 2026-08-08 12:00 |
04:50:20.68 |
-44:36:27.1 |
HIP 22537 |
20.52 |
| 2026-08-09 00:00 |
04:50:21.18 |
-44:36:36.2 |
HIP 22537 |
20.35 |
| 2026-08-09 12:00 |
04:50:21.66 |
-44:36:45.3 |
HIP 22537 |
20.17 |
| 2026-08-10 00:00 |
04:50:22.14 |
-44:36:54.5 |
HIP 22537 |
20.00 |
| 2026-08-10 12:00 |
04:50:22.62 |
-44:37:03.8 |
HIP 22537 |
19.83 |
| 2026-08-11 00:00 |
04:50:23.08 |
-44:37:13.1 |
HIP 22537 |
19.65 |
| 2026-08-11 12:00 |
04:50:23.54 |
-44:37:22.4 |
HIP 22537 |
19.48 |
| 2026-08-12 00:00 |
04:50:23.99 |
-44:37:31.8 |
HIP 22537 |
19.30 |
| 2026-08-12 12:00 |
04:50:24.42 |
-44:37:41.2 |
HIP 22537 |
19.13 |
| 2026-08-13 00:00 |
04:50:24.86 |
-44:37:50.7 |
HIP 22537 |
18.95 |
| 2026-08-13 12:00 |
04:50:25.28 |
-44:38:00.2 |
HIP 22537 |
18.78 |
| 2026-08-14 00:00 |
04:50:25.69 |
-44:38:09.7 |
HIP 22537 |
18.60 |
| 2026-08-14 12:00 |
04:50:26.10 |
-44:38:19.3 |
HIP 22537 |
18.43 |
| 2026-08-15 00:00 |
04:50:26.50 |
-44:38:29.0 |
HIP 22537 |
18.25 |
| 2026-08-15 12:00 |
04:50:26.89 |
-44:38:38.6 |
HIP 22537 |
18.08 |
| 2026-08-16 00:00 |
04:50:27.27 |
-44:38:48.3 |
HIP 22537 |
17.90 |
| 2026-08-16 12:00 |
04:50:27.64 |
-44:38:58.1 |
HIP 22537 |
17.73 |
| 2026-08-17 00:00 |
04:50:28.00 |
-44:39:07.9 |
HIP 22537 |
17.55 |
| 2026-08-17 12:00 |
04:50:28.36 |
-44:39:17.7 |
HIP 22537 |
17.38 |
| 2026-08-18 00:00 |
04:50:28.71 |
-44:39:27.5 |
HIP 22537 |
17.20 |
| 2026-08-18 12:00 |
04:50:29.04 |
-44:39:37.4 |
HIP 22537 |
17.03 |
| 2026-08-19 00:00 |
04:50:29.37 |
-44:39:47.3 |
HIP 22537 |
16.85 |