Asteroids

2021BA help

Last update: 2025-09-10 00:30 UTC

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.773

Aphelion (Q)

1.236

Eccentricity (e)

0.231

Inclination (i)

12.5

deg

Orbit period (P)

367.6

Earth MOID

0.00051

U parameter

0.6

Next Earth close approach

Date

2026-01-15

Nominal distance (from Earth center)

0.17264

25825983

Maximum Brightness

24.6

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

mag

Diameter

17 - 40*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-01-16

Observatory

Catalina Sky Survey

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

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.004217

1-sigma variation

8.030E-9

Unit

Eccentricity (e)

Value

0.230548

1-sigma variation

0.000001

Unit

Inclination (i)

Value

12.4557

1-sigma variation

0.0001

Unit

Long. of Ascending Node (Ω)

Value

116.9388

1-sigma variation

1.370E-6

Unit

Arg. of Perihelion (ω)

Value

98.6228

1-sigma variation

0.0001

Unit

Mean Anomaly (M)

Value

221.84716

1-sigma variation

0.00003

Unit

Perihelion distance

Value

0.772697

1-sigma variation

Unit

Aphelion distance

Value

1.235738

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.000771

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.098472

1-sigma variation

Unit

MOID

Value

0.000514

1-sigma variation

Unit

Orbit Period

Value

367.5699

1-sigma variation

Unit

U parameter

Value

0.6

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	6.44836E-17	-9.82135E-15	-5.53219E-13	2.49186E-15	-8.16705E-13	-2.58273E-13
e	-9.82135E-15	1.71086E-12	9.46572E-11	-3.66980E-13	1.41826E-10	3.82194E-11
i	-5.53219E-13	9.46572E-11	5.68725E-9	-3.99851E-11	7.88735E-9	2.06836E-9
Ω	2.49186E-15	-3.66980E-13	-3.99851E-11	1.87585E-12	-3.25848E-11	-7.33340E-12
ω	-8.16705E-13	1.41826E-10	7.88735E-9	-3.25848E-11	1.17621E-8	3.17119E-9
M	-2.58273E-13	3.82194E-11	2.06836E-9	-7.33340E-12	3.17119E-9	1.06747E-9

Date of computation: 2025-09-10 00:30 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

25.951

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

17 - 40*

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

727

Unit

Source

[1]

Unobserved

Value

1029

Unit

Source

[1]

Normalized RMS of residuals

Value

0.597142

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-01-16.255438

Unit

Source

[2]

Last Observation

Value

2023-01-13.2164

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

61 (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 2021BA 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	1996-08-17 22:47	1.4	0.1954231	0.1953664	0.0000189
EARTH	1997-08-15 06:33	1.6	0.1525192	0.1524696	0.0000165
EARTH	1998-08-12 10:05	1.7	0.1154461	0.1154077	0.0000128
EARTH	1999-08-09 09:22	1.8	0.0888572	0.0888368	0.0000068
EARTH	2000-08-04 23:36	2.1	0.0797605	0.0797564	0.0000014
EARTH	2001-07-31 21:10	2.5	0.0910664	0.0910435	0.0000076
EARTH	2002-07-26 13:19	3.1	0.1163698	0.1163384	0.0000105
EARTH	2003-07-19 10:30	4.0	0.1481432	0.1481102	0.0000110
EARTH	2004-07-09 07:08	4.9	0.1814304	0.1813995	0.0000103
EARTH	2017-01-14 21:01	< 1 min	0.1666685	0.1666602	0.0000028
EARTH	2018-01-18 12:48	< 1 min	0.1222284	0.1222217	0.0000022
EARTH	2019-01-19 10:17	< 1 s	0.0790933	0.0790885	0.0000016
EARTH	2020-01-19 03:16	< 1 min	0.0389755	0.0389729	0.0000009
EARTH	2021-01-17 14:18	< 1 s	0.0065779	0.0065777	0.0000000
EARTH	2022-01-18 07:47	< 1 s	0.0249797	0.0249787	0.0000003
EARTH	2023-01-19 05:50	< 1 s	0.0570001	0.0569989	0.0000004
EARTH	2024-01-19 21:49	< 1 s	0.0943043	0.0943031	0.0000004
EARTH	2025-01-18 13:22	< 1 min	0.1337863	0.1337852	0.0000004
EARTH	2026-01-15 05:52	< 1 min	0.1726360	0.1726350	0.0000004
EARTH	2039-07-05 06:32	1.7	0.1866857	0.1866726	0.0000044
EARTH	2040-07-13 06:54	1.3	0.1571016	0.1570876	0.0000047
EARTH	2041-07-20 07:05	1.0	0.1271693	0.1271552	0.0000047
EARTH	2042-07-25 16:31	< 1 min	0.0994955	0.0994826	0.0000043
EARTH	2043-07-29 18:29	< 1 min	0.0777232	0.0777133	0.0000033
EARTH	2044-08-01 02:49	< 1 min	0.0665157	0.0665115	0.0000014
EARTH	2045-08-04 02:49	< 1 min	0.0711273	0.0711237	0.0000012
EARTH	2046-08-07 01:00	< 1 min	0.0919169	0.0919066	0.0000034
EARTH	2047-08-09 22:15	< 1 min	0.1232014	0.1231867	0.0000049
EARTH	2048-08-11 15:21	< 1 min	0.1593770	0.1593594	0.0000058
EARTH	2049-08-14 08:26	< 1 min	0.1991988	0.1991793	0.0000065

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
274.88669647	14.56919756	0.00059697	MINIMUM
81.30891564	208.22064731	0.06692600	MINIMUM
358.92725547	110.99473035	0.30053916	SADDLE
177.46062735	292.20597704	0.33985790	SADDLE
3.23796744	296.63466201	1.75573386	SADDLE
183.96086813	117.44351505	2.23010325	MAXIMUM

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MOID Plots

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