Asteroids

1991BA help

Last update: 2025-03-28 16:24 UTC

Orbital Properties

Epoch

60800.0

MJD

Orbit type

Apollo

Perihelion (q)

0.701

Aphelion (Q)

3.498

Eccentricity (e)

0.666

Inclination (i)

2.1

deg

Orbit period (P)

1111.4

Earth MOID

0.00051

U parameter

9.0

Next Earth close approach

Date

2055-01-09

Nominal distance (from Earth center)

0.18616

27849433

Maximum Brightness

mag

Risk

Object is in risk list

Object is not in priority list

Physical Properties

Absolute Magnitude (H)

28.8

mag

Diameter

5 - 11*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

1991-01-18

Observatory

Steward Observatory, Kitt Peak-Spacewatch

ORBIT VISUALISATION TOOLS

External links

Proper elements

Epoch

Near present day

Near middle of observation arc

Orbit properties

Epoch
Semimajor Axis
Eccentricity (e)
Inclination (i)
Long. of Ascending Node (Ω)
Arg. of Perihelion (ω)
Mean Anomaly (M)
Perihelion distance
Aphelion distance
Asc. Node-Earth Sep.
Desc. Node-Earth Sep.
MOID
Orbit Period
U parameter

Value

1-sigma variation

Unit

Epoch

Value

60800.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

2.099836

1-sigma variation

0.002341

Unit

Eccentricity (e)

Value

0.666022

1-sigma variation

0.032392

Unit

Inclination (i)

Value

2.0856

1-sigma variation

0.5675

Unit

Long. of Ascending Node (Ω)

Value

117.3439

1-sigma variation

10.9222

Unit

Arg. of Perihelion (ω)

Value

74.3900

1-sigma variation

7.7613

Unit

Mean Anomaly (M)

Value

80.53553

1-sigma variation

251.76300

Unit

Perihelion distance

Value

0.701298

1-sigma variation

Unit

Aphelion distance

Value

3.498373

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.007771

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.405416

1-sigma variation

Unit

MOID

Value

0.000514

1-sigma variation

Unit

Orbit Period

Value

1111.4153

1-sigma variation

Unit

U parameter

Value

9.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	5.48074E-6	7.58325E-5	-1.32857E-3	2.55699E-2	-1.81700E-2	5.89400E-1
e	7.58325E-5	1.04928E-3	-1.83819E-2	3.53795E-1	-2.51401E-1	8.15520E0
i	-1.32857E-3	-1.83819E-2	3.22060E-1	-6.19826E0	4.40456E0	-1.42873E2
Ω	2.55699E-2	3.53795E-1	-6.19826E0	1.19294E2	-8.47701E1	2.74981E3
ω	-1.81700E-2	-2.51401E-1	4.40456E0	-8.47701E1	6.02382E1	-1.95400E3
M	5.89400E-1	8.15520E0	-1.42873E2	2.74981E3	-1.95400E3	6.33847E4

Date of computation: 2025-02-19 13:28 UTC

Note: The ASCII file is in a format suitable for Orbfit input.

Download ASCII file:

Physical properties

Rotation Period
Quality
Amplitude
Rotation Direction
Spinvector L
Spinvector B

Rotational properties

Value

Unit

Source

Rotation Period

Value

Unit

Source

[-]

Quality

Value

Unit

Source

[-]

Amplitude

Value

Unit

mag

Source

[-]

Rotation Direction

Value

Unit

Source

[-]

Spinvector L

Value

Unit

Source

[-]

Spinvector B

Value

Unit

Source

[-]

Taxonomy
Taxonomy (all)

Taxonomy

Value

Unit

Source

Taxonomy

Value

Unit

Source

[-]

Taxonomy (all)

Value

Unit

Source

[-]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

28.752

Unit

mag

Source

[1]

Slope Parameter (G)

Value

0.15**

Unit

mag

Source

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[2]

Diameter

Value

5 - 11*

Unit

Source

[2]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

Unit

mag

Source

[-]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Unit

Source

[-]

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Sources

No.	Name	Additional
[1]	ESA Aegis	ESA orbit determination and impact monitoring system
[2]	Estimation	Estimated from absolute magnitude

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

0.2

Unit

Source

[1]

Unobserved

Value

12488

Unit

Source

[1]

Normalized RMS of residuals

Value

0.0926681

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1991-01-18.2262

Unit

Source

[2]

Last Observation

Value

1991-01-18.41914

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

7 (0)

Unit

Source

[1]

Radar Summary

First Observation
Last Observation
Delay (Discarded)
Doppler (Discarded)
Total Optical Observations (Discarded)

Radar

Value

Unit

Source

First Observation

Value

Unit

Source

[-]

Last Observation

Value

Unit

Source

[-]

Delay (Discarded)

Value

0 (0)

Unit

Source

[-]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[-]

Total Radar Observations (Discarded)

Value

0 (0)

Unit

Source

[-]

Note: The ASCII file is in a format suitable for Orbfit input.

Sources

No.	Name	Additional
[1]	ESA Aegis	ESA orbit determination and impact monitoring system
[2]	MPC	Minor Planet Center: https://www.minorplanetcenter.net

Computation parameters

As seen from:

Initial Date: *

Final Date: *

Output option:

One line per time step

Time step:*

* - these fields are required

Close Approaches for 1991BA from 1950 to 2125

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au	Distance uncert. in au
EARTH	1965-06-12 06:50	> 1 mo	0.0379181	0.0196767	17.0573515
EARTH	1991-01-18 17:18	< 1 min	0.0011242	0.0009656	0.0000529
EARTH	2000-06-14 09:53	> 1 mo	0.0637032	0.0185497	7.5252849
EARTH	2003-07-01 04:23	> 1 mo	0.1805132	0.0181634	8.9011767
VENUS	2027-09-17 11:48	> 1 mo	0.0223486	0.0063879	3.1330691
EARTH	2055-01-09 17:44	> 1 mo	0.1861620	0.0011231	77.1882503
EARTH	2058-02-05 15:35	> 1 mo	0.1489666	0.0009405	71.2259304
EARTH	2064-06-06 05:35	> 1 mo	0.1218821	0.0175122	74.0071865
VENUS	2110-02-03 09:37	> 1 mo	0.0316167	0.0212674	11.0053326
EARTH	2113-01-16 18:20	> 1 mo	0.0496423	0.0008974	14.2859332
EARTH	2116-02-04 10:22	> 1 mo	0.1451132	0.0015606	2.9799308

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
322.98078146	16.02850327	0.00057166	MINIMUM
39.25627382	166.72955251	0.01762602	MINIMUM
1.61994391	92.08583016	0.29979197	SADDLE
1.56537280	271.96546174	1.70047614	SADDLE
180.32058307	270.27845148	2.49966380	SADDLE
180.30737325	90.27257754	4.49737005	MAXIMUM

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MOID Plots

Click on the images to zoom-in and zoom-out

Level lines of the squared distance function

1991BA

Date in UTC	MJD	σ	σ_imp	Distance ± Width in RE	Stretching in RE/σ	IP	Exp. energy	PS
2003-01-19.195	52658.195	-2.066	0.000	0.12 ± 0.108	1.63E5	7.02E-7	5.17E-9	n/a
2023-01-18.070	59962.070	0.938	0.000	0.24 ± 0.099	1.78E5	3.34E-6	1.03E-7	n/a
2026-01-17.658	61057.658	0.225	0.494	1.16 ± 48.969	2.52E6	2.55E-9	5.02E-11	-8.43
2027-01-19.190	61424.190	-3.669	0.000	0.54 ± 0.013	3.13E5	3.45E-9	1.62E-11	-9.12
2032-01-19.735	63250.735	-1.389	0.000	0.26 ± 0.049	5.84E5	6.15E-7	5.74E-9	-7.17
2036-01-19.840	64711.840	-1.121	0.000	0.44 ± 0.516	5.97E6	7.48E-8	7.82E-10	-8.24
2038-01-18.946	65441.946	-4.200	0.000	0.66 ± 0.037	2.73E5	4.72E-10	1.96E-12	-10.83
2041-01-18.727	66537.727	-3.292	0.000	0.94 ± 0.044	2.41E5	1.45E-8	7.51E-11	-9.35
2042-01-18.515	66902.515	0.279	0.000	0.98 ± 0.171	3.65E7	2.13E-8	4.38E-10	-8.74
2044-01-20.101	67634.101	-1.568	0.000	0.34 ± 0.333	2.56E5	1.05E-6	9.22E-9	-7.38
2048-01-19.671	69094.671	-4.278	0.000	0.64 ± 0.051	7.26E5	1.46E-10	5.96E-13	-11.59
2052-01-19.730	70555.730	-1.092	0.000	1.20 ± 0.250	9.44E5	1.63E-7	1.72E-9	-8.28
2053-01-18.902	70920.902	-0.584	0.000	1.00 ± 0.214	4.18E6	1.81E-7	2.39E-9	-8.17
2056-01-19.703	72016.703	-2.877	0.000	0.71 ± 0.079	3.52E6	4.43E-9	2.57E-11	-10.11
2061-01-19.419	73843.419	-1.308	0.000	0.85 ± 0.268	1.88E6	2.09E-7	2.01E-9	-8.33
2066-01-19.320	75669.320	-3.067	0.000	0.52 ± 0.045	7.04E6	1.17E-9	6.44E-12	-10.83
2073-01-19.095	78226.095	-3.379	0.000	0.77 ± 0.053	2.16E5	1.50E-8	7.59E-11	-9.82
2075-01-20.315	78957.315	-0.936	1.796	1.20 ± 1.431	2.87E5	1.85E-9	2.09E-11	-10.47
2077-01-19.791	79687.791	-1.568	0.000	0.98 ± 1.056	3.14E7	4.46E-9	3.92E-11	-10.19
2078-01-19.772	80052.772	-1.426	0.000	0.69 ± 0.164	3.55E5	7.89E-7	7.27E-9	-7.94
2078-01-19.774	80052.774	-1.425	0.000	0.87 ± 0.169	3.46E5	8.05E-7	7.42E-9	-7.93
2089-01-19.732	84070.732	-1.346	0.000	0.48 ± 0.149	1.94E7	1.94E-8	1.84E-10	-9.61
2090-01-19.778	84435.778	-1.737	0.000	0.72 ± 0.306	3.10E7	6.48E-9	5.34E-11	-10.15
2091-01-19.840	84800.840	-3.917	0.000	0.14 ± 0.290	9.67E5	4.68E-10	2.08E-12	-11.51
2094-01-19.782	85896.782	-1.609	0.000	1.15 ± 0.161	3.27E6	2.58E-8	2.22E-10	-9.55
2098-01-19.871	87357.871	-1.660	0.000	1.17 ± 0.370	9.57E6	9.19E-9	7.78E-11	-10.03
2100-01-20.210	88088.210	-0.857	0.000	0.71 ± 0.101	2.69E7	2.45E-8	2.85E-10	-9.51
2100-01-20.257	88088.257	-0.855	0.000	1.20 ± 1.526	5.00E6	4.33E-8	5.07E-10	-9.26
2106-01-01.762	90260.762	1.686	1.495	0.89 ± 0.777	7.19E6	5.04E-11	2.61E-12	-11.71
2114-01-19.934	93200.934	-0.258	0.000	1.17 ± 0.365	6.28E5	1.16E-6	1.80E-8	-7.80
2115-01-21.383	93567.383	-0.953	0.000	1.14 ± 0.362	7.37E6	4.01E-8	4.49E-10	-9.38
2115-01-21.493	93567.493	-3.487	0.699	1.25 ± 0.735	2.48E5	3.14E-9	1.55E-11	-10.77


Based on 7 optical observations (of which 0 are rejected as outliers) from 1991/01/18.226 to 1991/01/18.419.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.20 and 1.20 Earth radii.
Coordinates for LOV = EQU scaled= 1 second= F.
AstOD software version= 4.0, Date of computation=20250305 090509.040 UTC.

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