Asteroids

2012HE31 help

Last update: 2025-11-24 16:53 UTC

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.840

Aphelion (Q)

1.930

Eccentricity (e)

0.394

Inclination (i)

0.5

deg

Orbit period (P)

595.3

Earth MOID

0.00304

U parameter

8.6

Next Earth close approach

Date

2038-06-30

Nominal distance (from Earth center)

0.17506

26188925

Maximum Brightness

42.1

mag

Risk

Object is in risk list

Physical Properties

Absolute Magnitude (H)

26.2

mag

Diameter

15 - 30*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2012-04-27

Observatory

Lincoln Laboratory ETS, New Mexico

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

1.384942

1-sigma variation

0.003065

Unit

Eccentricity (e)

Value

0.393554

1-sigma variation

0.000629

Unit

Inclination (i)

Value

0.5241

1-sigma variation

0.0197

Unit

Long. of Ascending Node (Ω)

Value

10.3256

1-sigma variation

1.2088

Unit

Arg. of Perihelion (ω)

Value

275.1208

1-sigma variation

0.9568

Unit

Mean Anomaly (M)

Value

93.12561

1-sigma variation

1.02768

Unit

Perihelion distance

Value

0.839892

1-sigma variation

Unit

Aphelion distance

Value

1.929992

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.129013

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.213768

1-sigma variation

Unit

MOID

Value

0.003045

1-sigma variation

Unit

Orbit Period

Value

595.3136

1-sigma variation

Unit

U parameter

Value

8.6

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	9.39442E-6	1.92679E-6	-6.05294E-5	-3.70505E-3	2.93267E-3	3.14988E-3
e	1.92679E-6	3.95183E-7	-1.24145E-5	-7.59903E-4	6.01488E-4	6.46040E-4
i	-6.05294E-5	-1.24145E-5	3.89999E-4	2.38721E-2	-1.88955E-2	-2.02951E-2
Ω	-3.70505E-3	-7.59903E-4	2.38721E-2	1.46123E0	-1.15661E0	-1.24228E0
ω	2.93267E-3	6.01488E-4	-1.88955E-2	-1.15661E0	9.15494E-1	9.83303E-1
M	3.14988E-3	6.46040E-4	-2.02951E-2	-1.24228E0	9.83303E-1	1.05614E0

Date of computation: 2025-11-24 16:53 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

26.25

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

15 - 30*

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

Unit

Source

[1]

Unobserved

Value

4973

Unit

Source

[1]

Normalized RMS of residuals

Value

0.857154

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2012-04-13.417854

Unit

Source

[2]

Last Observation

Value

2012-04-29.479639

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

24 (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 2012HE31 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	1957-09-04 06:17	> 1 w	0.0767073	0.0039304	0.0537230
EARTH	1970-05-14 14:41	> 1 w	0.0935248	0.0038358	0.0387227
EARTH	1978-09-08 14:06	> 1 d	0.0553404	0.0054666	0.0171460
EARTH	1991-05-06 12:22	> 1 d	0.0515952	0.0043972	0.0478683
EARTH	1999-08-26 22:30	> 1 w	0.1101400	0.0247950	0.0284878
EARTH	2012-04-30 08:17	< 1 s	0.0069694	0.0069568	0.0000042
EARTH	2020-09-23 15:35	> 1 d	0.1359459	0.0640898	0.0239580
EARTH	2025-05-02 14:14	> 1 d	0.0236298	0.0045364	0.0331503
EARTH	2038-06-30 00:35	> 1 mo	0.1750621	0.1019432	0.0243946
EARTH	2051-09-01 23:53	> 1 mo	0.0853707	0.0025144	0.4195219
EARTH	2056-04-20 05:29	> 1 w	0.1389504	0.0044233	0.4554784
EARTH	2064-09-22 02:27	> 1 w	0.1099219	0.0029568	0.2787665
EARTH	2069-05-09 20:36	> 1 w	0.0696276	0.0044910	0.1090776
EARTH	2082-07-19 13:15	> 1 mo	0.1724418	0.0033774	0.0571044
EARTH	2095-09-16 02:25	> 1 mo	0.0146430	0.0029476	0.7540146
EARTH	2100-05-27 23:01	> 1 mo	0.1249187	0.0031967	3.9216589
MARS	2109-11-17 09:04	> 1 mo	0.0448478	0.0427355	3.8188580
EARTH	2118-07-29 08:19	> 1 mo	0.1639880	0.0016174	7.2964384
EARTH	2123-04-27 10:01	> 1 mo	0.0730274	0.0048389	29.9307643

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
46.05092356	250.65748114	0.00304457	MINIMUM
313.62531188	117.27030550	0.00453466	MINIMUM
359.80233518	183.92323044	0.17843316	SADDLE
179.91562700	4.04931584	0.94648784	SADDLE
359.81328664	3.93732588	1.82346011	SADDLE
179.91414743	184.04710763	2.94808645	MAXIMUM

Download:

MOID Plots

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

Level lines of the squared distance function

2012HE31

Date in UTC	MJD	σ	Distance ± Width in RE	Stretching in RE	IP	Impact energy	PS
2046-09-15.585	68603.585	-0.709	1.32 ± 0.004	2.11E7	2.49E-8	3.80E-1	-7.77
2059-09-15.954	73351.954	-0.705	1.45 ± 0.004	1.54E7	6.25E-9	3.81E-1	-8.57
2062-09-15.830	74447.830	-1.020	0.71 ± 0.004	9.11E6	6.61E-8	3.81E-1	-7.58
2075-09-15.579	79195.579	-1.021	1.35 ± 0.004	1.32E7	1.96E-8	3.81E-1	-8.23
2094-09-12.622	86132.622	-0.539	0.49 ± 0.005	7.70E6	1.23E-7	3.80E-1	-7.57
2094-09-12.984	86132.984	-0.583	1.27 ± 0.005	3.78E6	1.56E-7	3.81E-1	-7.46
2095-09-14.844	86499.844	-0.497	0.05 ± 0.179	3.18E7	3.20E-8	3.81E-1	-8.16
2100-09-14.788	88325.788	-0.689	0.17 ± 0.000	4.52E6	2.02E-7	3.81E-1	-7.38
2108-09-15.356	91248.356	-0.113	1.04 ± 0.000	3.62E8	2.47E-9	3.81E-1	-9.34
2109-09-17.300	91615.300	-0.731	0.25 ± 0.000	6.19E7	1.42E-8	3.80E-1	-8.59


Based on 24 optical observations (of which 0 are rejected as outliers) from 2012/04/13.418 to 2012/04/29.480.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.45 and 1.45 Earth radii.
Coordinates for LOV = EQU scaled= 1 second= F.
AstOD software version= 4.0, Date of computation=20250805 130500.123 UTC.

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