Potentially Hazardous Asteroid Database

PHA Catalogue — NASA/JPL CNEOS

PHA criteria: Minimum Orbit Intersection Distance (MOID) ≤ 0.05 au and absolute magnitude H ≤ 22.0 (diameter ≳ 140 m). Defined by the IAU/MPC. Term coined by Brian Marsden, 1995.

Torino Impact Hazard Scale

0 — No hazard 1 — Normal 2–4 — Concern 5–7 — Threat 8–10 — Certain

Torino 0 — No hazard Torino 1 — Very low Torino 2–3 — Attention Torino 4+ — Concern

Designation / Name H mag Diam. MOID Period Torino

Largest known PHAs

(53319) 1999 JM8

1999 JM8

Apollo · C-type

15.2

~7 km

0.0396 au

3.49 yr

Discovered

1999 May 27

Discoverers

LINEAR

Albedo

0.02–0.03 (very dark)

Rotation period

~136 h (tumbling)

Eccentricity

0.699

Inclination

25.1°

Semi-major axis

2.724 au

Impact prob.

None known

Likely the largest known PHA at ~7 km diameter, despite a fainter absolute magnitude due to its extremely low albedo of ~0.02. Radar imaging by Goldstone and Arecibo revealed a non-principal axis (tumbling) rotation, similar to Toutatis. Source: JPL SBDB · Wikipedia (MPC data)

(4183) Cuno

Cuno

Apollo · S-type

14.4

~5.6 km

0.0062 au

2.27 yr

Discovered

1959 Aug 24

Discoverers

J.J. Johnson (IUA)

Albedo

~0.27

Rotation period

2.98 h

Eccentricity

0.637

Inclination

6.7°

Semi-major axis

1.982 au

Impact prob.

None known

Second-largest known PHA at ~5.6 km. An Apollo asteroid with a very low MOID of 0.0062 au. Named after Cuno Hoffmeister, German astronomer. Source: JPL SBDB · MPC

(3200) Phaethon

Phaethon DESTINY+

Apollo · B/F-type · Geminid parent

14.4

~5.8 km

0.0202 au

1.43 yr

Discovered

1983 Oct 11 (IRAS)

Discoverers

S. Green, J. Davies

Albedo

~0.107

Rotation period

3.604 h

Eccentricity

0.890

Inclination

22.3°

Perihelion

0.140 au (Sun-grazer)

Impact prob.

None known

Parent body of the Geminid meteor shower. Discovered by NASA's IRAS satellite. Perihelion of 0.140 au makes its surface reach ~750°C. Blue-type asteroid with active dust emission near perihelion — classified as both asteroid and "rock comet". Target of JAXA's DESTINY+ mission (planned 2024–). Source: JPL SBDB · CNEOS · JAXA

High-profile & mission targets

(99942) Apophis

Apophis OSIRIS-APEX Ramses

Aten · Sq-type

19.7

~340 m

0.000037 au

0.89 yr

Discovered

2004 Jun 19

Discoverers

Tucker, Tholen, Bernardi

Observatory

Kitt Peak (966)

Albedo

0.33 ± 0.08

Spectral type

Sq (S/LL chondrite)

Eccentricity

0.191

Semi-major axis

0.922 au

Inclination

3.34°

Close approach

2029 Apr 13 (~31,600 km)

Rotation period

27.38 h (tumbling)

Peak Torino

4 (Dec 2004 — rescinded)

Impact prob.

None <100 yr (JPL 2021)

Impact risk (2029–2036)

0.000%

Most famous PHA. Peaked at Torino Scale 4 in December 2004 — the highest ever recorded — with 2.7% impact probability for 2029. All risk eliminated by 2021 radar observations. The 2029 flyby at ~31,600 km will be closer than geosynchronous satellites and visible to the naked eye from Europe/Africa/Asia. NASA's OSIRIS-APEX and ESA's Ramses will study it. Source: JPL/CNEOS · Britannica · USGS 2025

(101955) Bennu

Bennu OSIRIS-REx

Apollo · B-type

20.5

~490 m

0.0032 au

1.20 yr

Discovered

1999 Sep 11

Discoverers

LINEAR

Albedo

0.044 (very dark)

Rotation period

4.297 h

Eccentricity

0.204

Semi-major axis

1.126 au

Inclination

6.03°

Composition

Carbon-rich, hydrated

Key impact date

2182 Sep 24 (highest prob.)

Impact probability

0.037% (2175–2199 window)

Palermo scale

~–1.6 (highest known)

Impact energy

~1.4 Gt TNT equiv.

Cumulative impact prob. 2175–2199

0.057%

Currently the highest Palermo Scale rated asteroid (~–1.6), making it the single greatest calculated impact threat. OSIRIS-REx returned a 121.6 g sample on 2023 Sep 24 — the largest asteroid sample returned to Earth by a US mission. Source: JPL/CNEOS · NASA OSIRIS-REx · ESA NEOCC

(29075) 1950 DA

1950 DA

Apollo · E/M-type

17.0

~1.3 km

0.0041 au

2.22 yr

Discovered

1950 Feb 23

Discoverers

C. Wirtanen (Lick Obs.)

Lost / recovered

Lost 1950; recovered 2000

Albedo

~0.20 (moderate)

Rotation period

2.1216 h (retrograde)

Eccentricity

0.508

Semi-major axis

1.698 au

Inclination

12.2°

Impact date

2880 Mar 16

Impact probability

0.0029% (1-in-34,500)

Palermo scale

~–2.7

Impact energy

~75 Gt TNT equiv.

2880 impact probability

0.0029%

Observed only in 1950 before being lost, then rediscovered in December 2000. One of the second-most hazardous objects on Sentry by Palermo Scale (after Bennu). Impact at 1.3 km diameter would be a global catastrophe. Yarkovsky effect is a key source of orbital uncertainty at such long timescales. Source: JPL/CNEOS Sentry · Purdue/UNC radar data

(65803) Didymos

Didymos DART Hera

Apollo · Sq-type · Binary

18.2

~780 m

0.0453 au

2.11 yr

Discovered

1996 Apr 11

Discoverers

Spacewatch (Lagerkvist)

Moonlet (Dimorphos)

~160 m diameter

Albedo

0.16

Rotation period

2.26 h

Eccentricity

0.384

Semi-major axis

1.644 au

DART impact

2022 Sep 26 (successful)

Period change

−33 min (11.92→11.37 h)

Impact prob.

None known

Target of NASA's DART mission — the world's first planetary defense test. Impact on moonlet Dimorphos on 2022 Sep 26 changed its orbital period by ~33 minutes, confirming kinetic impactor technology works. ESA's Hera spacecraft arrived in early 2025 to study the aftermath. Source: NASA DART · ESA Hera · Johns Hopkins APL

Classical & historically significant PHAs

(1566) Icarus

Icarus

Apollo · S-type · Mercury-crosser

16.4

~1.4 km

0.0352 au

1.12 yr

Discovered

1949 Jun 27

Discoverers

W. Baade (Palomar)

Albedo

0.33

Rotation period

2.273 h

Eccentricity

0.827

Perihelion

0.187 au (Sun-grazer)

Semi-major axis

1.078 au

Inclination

22.9°

First radar obs.

1968 (first ever)

Impact prob.

None known

Named after the Greek mythological figure. In 1968 it became the first asteroid ever observed by radar (Goldstone DSS-14). Crosses orbits of Mercury, Venus, Earth and Mars. Probable parent body of the Arietids daytime meteor shower. Source: JPL SBDB · Wikipedia (MPC data)

(4179) Toutatis

Toutatis Chang'e 2

Apollo · Sq-type · Elongated

15.3

~2.5 km

0.0062 au

3.98 yr

Discovered

1989 Jan 4

Discoverers

C. Pollas (OCA)

Dimensions

4.5 × 2.4 × 1.9 km

Albedo

0.13

Rotation

Non-principal axis (tumbling)

Eccentricity

0.634

Semi-major axis

2.512 au

Chang'e 2 flyby

2012 Dec 13 (~3.2 km)

Impact prob.

None known

Extensively studied by radar — reveals a "peanut" contact-binary shape, suggesting two lobes. One of the most closely tracked PHAs of the 1990s–2000s with repeated Earth flybys ~4 yr cycle. Imaged by China's Chang'e 2 spacecraft at ~3.2 km range in 2012 — first asteroid flyby by a Chinese spacecraft. Source: JPL SBDB · CNSA · MPC

(162173) Ryugu

Ryugu Hayabusa2

Apollo · C/Cb-type · Spinning-top

18.7

~870 m

0.0011 au

1.30 yr

Discovered

1999 May 10

Discoverers

LINEAR

Albedo

0.045 (very dark)

Rotation period

7.627 h

Eccentricity

0.190

Semi-major axis

1.190 au

Inclination

5.88°

Sample returned

2020 Dec 6 (5.4 g)

Impact prob.

None known

JAXA's Hayabusa2 orbited Ryugu 2018–2019, deployed multiple landers (MASCOT, MINERVA-II), and performed two sample collections. 5.4 g of pristine carbonaceous material returned Dec 2020 — found to contain amino acids and liquid water inclusions, informing theories of life's origins. Source: JAXA · MPC · Science (Watanabe et al.)

Active Sentry risk objects (selected)

2024 YR4

Apollo · S-type (provisional)

25.7

40–90 m

~0.00 au

~2.1 yr

Discovered

2024 Dec 27 (ATLAS)

Observatory

ATLAS Rio Hurtado, Chile

Size estimate

40–90 m (brightness-based)

Prior close approach

2024 Dec 25

Peak Torino level

3 (2025 Jan 28 — rescinded)

Peak impact prob.

3.1% for 2032 Dec 22

Current prob.

<0.001% — ruled out

Next approach

2028 (~20× Earth-Moon dist.)

Peak impact prob. (2025 Feb 18)

3.1%

Reached Torino Scale 3 on 2025 Jan 28 — the highest rating for any object in ~20 years. Peak probability of 3.1% on 2025 Feb 18 was the highest ever recorded for a hazardous-sized object. Subsequent VLT and Magdalena Ridge observations fully eliminated the 2032 impact threat. Spectral type consistent with S or L class (GTC-Z18, Dr. Julia de León, 2025 Jan 13). Source: NASA CNEOS · JPL Sentry · ESA NEOCC · PDCO Lessons Learned Report (2025)

2023 TL4

Apollo (provisional)

~23.5

~100–200 m

—

~2 yr

Discovered

2023

Sentry listing

Active — low probability

Orbital arc

Short — needs refinement

Status

Under observation

A recently discovered object with an early Sentry listing. Short observation arcs result in larger orbital uncertainties. Further observations expected to resolve or eliminate impact scenarios. Source: JPL Sentry · CNEOS

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Potentially Hazardous Asteroid Database

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