Asteroids

2021RO16 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.873

Aphelion (Q)

1.499

Eccentricity (e)

0.264

Inclination (i)

0.4

deg

Orbit period (P)

471.7

Earth MOID

0.00352

U parameter

7.1

Next Earth close approach

Date

2034-04-23

Nominal distance (from Earth center)

0.01465

2191237

Maximum Brightness

21.1

mag

Risk

Object is in risk list

Physical Properties

Absolute Magnitude (H)

26.5

mag

Diameter

13 - 30*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-09-14

Observatory

ATLAS-MLO, Mauna Loa

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

1.185952

1-sigma variation

0.000204

Unit

Eccentricity (e)

Value

0.264082

1-sigma variation

0.000198

Unit

Inclination (i)

Value

0.4141

1-sigma variation

0.0003

Unit

Long. of Ascending Node (Ω)

Value

60.1028

1-sigma variation

0.0097

Unit

Arg. of Perihelion (ω)

Value

219.3424

1-sigma variation

0.0101

Unit

Mean Anomaly (M)

Value

131.54848

1-sigma variation

0.33476

Unit

Perihelion distance

Value

0.872763

1-sigma variation

Unit

Aphelion distance

Value

1.499140

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.396537

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.096615

1-sigma variation

Unit

MOID

Value

0.003521

1-sigma variation

Unit

Orbit Period

Value

471.7359

1-sigma variation

Unit

U parameter

Value

7.1

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	4.16314E-8	4.04061E-8	6.27839E-8	-1.93204E-6	1.99372E-6	-6.83041E-5
e	4.04061E-8	3.92179E-8	6.09241E-8	-1.87328E-6	1.93301E-6	-6.62939E-5
i	6.27839E-8	6.09241E-8	9.48608E-8	-2.94302E-6	3.03761E-6	-1.03009E-4
Ω	-1.93204E-6	-1.87328E-6	-2.94302E-6	9.48418E-5	-9.79540E-5	3.16987E-3
ω	1.99372E-6	1.93301E-6	3.03761E-6	-9.79540E-5	1.01177E-4	-3.27107E-3
M	-6.83041E-5	-6.62939E-5	-1.03009E-4	3.16987E-3	-3.27107E-3	1.12066E-1

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

26.519

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

13 - 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

1438

Unit

Source

[1]

Normalized RMS of residuals

Value

0.680212

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-09-14.448731

Unit

Source

[2]

Last Observation

Value

2021-10-14.31294

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

33 (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 2021RO16 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	1952-06-03 01:55	> 1 mo	0.1327312	0.0202161	140.9858705
EARTH	1961-04-07 16:39	> 1 mo	0.1486595	0.0091906	187.7135007
EARTH	1966-09-09 23:39	> 1 mo	0.0065376	0.0065371	0.0197283
EARTH	1975-06-27 07:33	> 1 mo	0.1465050	0.1149803	0.0554802
EARTH	1984-04-16 02:31	> 1 w	0.0197091	0.0071746	0.2184555
EARTH	1989-09-13 03:22	> 1 w	0.0281988	0.0068993	0.0993922
EARTH	1998-06-17 05:43	> 1 mo	0.1432060	0.1059957	0.0130544
EARTH	2007-04-10 17:26	> 1 d	0.1215767	0.0003384	0.0473149
EARTH	2012-09-11 06:16	> 1 d	0.0092691	0.0068830	0.0102299
EARTH	2021-09-11 05:04	< 1 min	0.0073410	0.0073256	0.0000051
EARTH	2034-04-23 08:56	> 1 d	0.0146475	0.0034412	0.0197945
EARTH	2043-09-12 16:55	> 1 w	0.0252836	0.0071525	0.3305998
EARTH	2047-04-19 23:48	> 1 mo	0.0306639	0.0029033	0.4893842
EARTH	2056-09-10 18:51	> 1 d	0.0081953	0.0072303	0.0708340
EARTH	2060-04-24 07:27	> 1 mo	0.0097808	0.0012397	2.5748503
EARTH	2077-09-19 15:46	> 1 mo	0.1499825	0.0073785	204.5617826
EARTH	2081-07-26 20:37	> 1 mo	0.1242050	0.0119548	74.0311135
EARTH	2085-04-25 20:35	> 1 mo	0.0184771	0.0013488	220.6748148
EARTH	2110-09-16 18:19	> 1 mo	0.0896452	0.0076414	7129.4907692
EARTH	2114-08-10 18:40	> 1 mo	0.1046502	0.0084823	3428.4432248
EARTH	2118-06-05 06:50	> 1 mo	0.1199383	0.0084728	1713.7555757
EARTH	2122-04-20 05:56	> 1 mo	0.0567055	0.0014386	2474.2087145

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
305.30246999	108.05395012	0.00348550	MINIMUM
55.04147018	246.72093440	0.00694867	MINIMUM
0.21639762	177.44123140	0.14363058	SADDLE
180.11515830	357.32283548	0.51553281	SADDLE
0.17820164	357.39183066	1.85638262	SADDLE
180.10625557	177.31705908	2.51544540	MAXIMUM

Download:

MOID Plots

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

Level lines of the squared distance function

2021RO16

Date in UTC	MJD	σ	σ_imp	Distance ± Width in RE	Stretching in RE	IP	Impact energy	PS	TS
2101-04-24.541	88547.541	-0.148	0.000	0.43 ± 0.000	2.19E7	6.38E-8	1.27E-1	-8.27	0


Based on 33 optical observations (of which 0 are rejected as outliers) from 2021/09/14.449 to 2021/10/14.313.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.78 and 1.78 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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Download Impactor Table as: