Asteroids

251732 1998HG49 help

Last update: 2025-07-29 02:36 UTC

Orbital Properties

Epoch

60800.0

MJD

Orbit type

Amor

Perihelion (q)

1.066

Aphelion (Q)

1.336

Eccentricity (e)

0.112

Inclination (i)

4.2

deg

Orbit period (P)

480.5

Earth MOID

0.07677

U parameter

0.4

A₂

-95.4

10^-15au/days²

Next Earth close approach

Date

2031-07-27

Nominal distance (from Earth center)

0.16356

24468029

Maximum Brightness

19.6

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

21.7

mag

Diameter

120 - 270*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

1998-04-27

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

1.200554

1-sigma variation

9.031E-9

Unit

Eccentricity (e)

Value

0.112437

1-sigma variation

7.610E-8

Unit

Inclination (i)

Value

4.1950

1-sigma variation

3.747E-6

Unit

Long. of Ascending Node (Ω)

Value

44.8043

1-sigma variation

4.119E-5

Unit

Arg. of Perihelion (ω)

Value

324.2735

1-sigma variation

0.0001

Unit

Mean Anomaly (M)

Value

38.54231

1-sigma variation

0.00004

Unit

Perihelion distance

Value

1.065567

1-sigma variation

Unit

Aphelion distance

Value

1.335541

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.095190

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.295932

1-sigma variation

Unit

MOID

Value

0.076765

1-sigma variation

Unit

Orbit Period

Value

480.4750

1-sigma variation

Unit

U parameter

Value

0.4

1-sigma variation

Unit

A₂

Value

-95.41459

1-sigma variation

17.63690

Unit

10^-15au/days²

Covariance Matrix

	a	e	i	Ω	ω	M	A₂
a	8.15593E-17	-5.16383E-16	-4.24061E-15	-3.80951E-15	1.98089E-13	-3.21664E-13	1.57751E-7
e	-5.16383E-16	5.79060E-15	2.84137E-14	8.06778E-14	-7.62468E-13	1.29056E-12	-1.02503E-6
i	-4.24061E-15	2.84137E-14	1.40410E-11	-2.95686E-11	1.16889E-11	2.60851E-11	-8.24588E-6
Ω	-3.80951E-15	8.06778E-14	-2.95686E-11	1.69666E-9	-1.65599E-9	-4.24887E-11	-9.30881E-6
ω	1.98089E-13	-7.62468E-13	1.16889E-11	-1.65599E-9	2.54868E-9	-1.28879E-9	3.79475E-4
M	-3.21664E-13	1.29056E-12	2.60851E-11	-4.24887E-11	-1.28879E-9	1.96541E-9	-6.09398E-4
A₂	1.57751E-7	-1.02503E-6	-8.24588E-6	-9.30881E-6	3.79475E-4	-6.09398E-4	3.11059E2

Date of computation: 2025-07-29 02:36 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

21.702

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

120 - 270*

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

9145

Unit

Source

[1]

Unobserved

Value

847

Unit

Source

[1]

Normalized RMS of residuals

Value

0.61282

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1998-04-27.20297

Unit

Source

[2]

Last Observation

Value

2023-05-11.343765

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

156 (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 251732 1998HG49 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	1956-08-03 16:24	126.1	0.1550522	0.1550446	0.0000025
EARTH	1960-11-21 01:45	8.4	0.1569524	0.1569439	0.0000028
EARTH	1981-07-27 00:40	17.2	0.1635943	0.1635910	0.0000011
EARTH	1985-11-16 08:52	3.2	0.1466272	0.1466236	0.0000012
EARTH	2006-07-23 15:51	1.1	0.1681251	0.1681248	0.0000001
EARTH	2010-11-14 12:27	< 1 min	0.1422239	0.1422236	0.0000001
EARTH	2031-07-27 23:36	7.1	0.1635587	0.1635573	0.0000005
EARTH	2035-11-18 15:38	2.4	0.1496095	0.1496069	0.0000009
EARTH	2056-08-05 02:21	125.4	0.1553418	0.1553357	0.0000020
EARTH	2060-11-22 18:09	7.9	0.1590025	0.1589947	0.0000026
EARTH	2081-08-06 13:43	216.2	0.1543035	0.1542955	0.0000027
EARTH	2085-11-22 18:33	9.4	0.1586995	0.1586902	0.0000031
EARTH	2106-07-31 05:41	30.5	0.1620166	0.1620121	0.0000015
EARTH	2110-11-19 07:47	4.8	0.1490073	0.1490020	0.0000018

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
8.11491990	276.85631603	0.07676547	MINIMUM
169.97497191	77.27613349	0.34231442	SADDLE
351.74251965	78.53600765	2.06275864	SADDLE
174.43211408	261.24840781	2.33648356	MAXIMUM

Download:

MOID Plots

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