Wikipedia

(7482) 1994 PC1

(7482) 1994 PC1 is a stony asteroid and near-Earth object, currently estimated to be the most potentially hazardous asteroid over the next 1000 years.[6][7] It is in the Apollo group, approximately 1.1 kilometers in diameter. It was discovered on 9 August 1994, by astronomer Robert McNaught at the Siding Spring Observatory in Coonabarabran, Australia.[2] With an observation arc of 47 years it has a very well known orbit and was observed by Goldstone radar in January 1997.[8]

(7482) 1994 PC1
Orbit with positions Jan 2020
Discovery[1]
Discovered byR. H. McNaught
Discovery siteSiding Spring Obs.
Discovery date9 August 1994
Designations
(7482) 1994 PC1
1994 PC1
Apollo · NEO · PHA[1][2]
Orbital characteristics[1]
Epoch 2022-Jan-21 (JD 2459600.5)
Uncertainty parameter 0
Observation arc47.23 yr (17,251 days)
Earliest precovery date22 September 1974
Aphelion1.7935 AU
Perihelion0.9042 AU
1.3488 AU
Eccentricity0.3297
1.56 yr (572 days)
337.27°
0° 37m 51.6s / day
Inclination33.479°
117.88°
47.477°
Earth MOID0.00054 AU (0.21 LD)
Mars MOID0.139 AU (20.8 million km)[2]
Physical characteristics
1.052±0.303 km[3]
1.30 km (calculated)[4]
2.5999 h[5]
0.277±0.185[3]
0.20 (assumed)[4]
SMASS = S[1][4]
16.6[1][4] · 16.80±0.3[3]

Of all the known asteroids larger than 1 km, 1994 PC1 has the largest probability of a “deep close encounter” with us over the next 1000 years. It has a close encounter with Earth in 2525, after which the uncertainty of its orbit increases.[6]

Orbit and classification

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1994 PC1 orbits the Sun at a distance of 0.9–1.8 AU once every 1 years and 7 months (572 days). Its orbit has an eccentricity of 0.33 and an inclination of 33° with respect to the ecliptic.[1]

On 17 January 1933, it passed 811,350 km (504,150 mi) from the Moon and then about an hour later made its closest known approach to Earth of 1,125,400 km (699,300 mi).[1] On 18 January 2022, it passed about 1,981,468 km (1,231,227 mi) from Earth.[1]

Close approaches[1]
Date JPL SBDB
nominal geocentric
distance 		uncertainty
region
(3-sigma)
1933-01-17 1125383 km ± 65 km[a]
2022-01-18 1981468 km ± 47 km[9]
2105-01-18 2328125 km ± 1069 km[10]

Physical characteristics

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In the SMASS classification, 1994 PC1 is a common stony S-type asteroid.[1][4]

Rotation period

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In 1998, a rotational lightcurve of 1994 PC1 was obtained from photometric observations by Petr Pravec. Lightcurve analysis gave a well-defined rotation period of 2.5999 hours with a brightness amplitude of 0.29 magnitude (U=3).[5]

Diameter and albedo

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According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 1994 PC1 measures 1.052 kilometers in diameter and its surface has an albedo of 0.277.[3] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.20 and calculates a diameter of 1.30 kilometers based on an absolute magnitude of 16.8.[4]

2022 flyby

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At 18 January 2022 21:51 UTC, 1994 PC1 passed 5.15 lunar distances from Earth[1] and had a 3-sigma uncertainty region of less than ± 50 km.[9] It peaked at an apparent magnitude of about 10[11] placing it just outside the reach of common 7×50 binoculars. The nearly Full moon being about 100 degrees from the asteroid during closest approach may have made it more difficult to observe with smaller telescopes.

2022 Moon/Earth approach
Date & Time Approach
to 		Nominal distance
2022-01-18 18:58 Moon 2085780 km[12]
2022-01-18 21:51 Earth 1981468 km[1]
 
Animation of 1994 PC1 - 2022 close approach
  Sun ·   Earth ·   1994 PC1
Sky trajectory with daily motion
 
History of close approaches of large near-Earth objects since 1908 (A)
PHA Date Approach distance (lunar dist.) Abs.
mag
(H) 		Diameter (C)
(m) 		Ref (D)
Nomi-
nal(B) 		Mini-
mum 		Maxi-
mum
(33342) 1998 WT24 1908-12-16 3.542 3.537 3.547 17.9 556–1795 data
(458732) 2011 MD5 1918-09-17 0.911 0.909 0.913 17.9 556–1795 data
(7482) 1994 PC1 1933-01-17 2.927 2.927 2.928 16.8 749–1357 data
69230 Hermes 1937-10-30 1.926 1.926 1.927 17.5 668–2158 data
69230 Hermes 1942-04-26 1.651 1.651 1.651 17.5 668–2158 data
(137108) 1999 AN10 1946-08-07 2.432 2.429 2.435 17.9 556–1795 data
(33342) 1998 WT24 1956-12-16 3.523 3.523 3.523 17.9 556–1795 data
(163243) 2002 FB3 1961-04-12 4.903 4.900 4.906 16.4 1669–1695 data
(192642) 1999 RD32 1969-08-27 3.627 3.625 3.630 16.3 1161–3750 data
(143651) 2003 QO104 1981-05-18 2.761 2.760 2.761 16.0 1333–4306 data
2017 CH1 1992-06-05 4.691 3.391 6.037 17.9 556–1795 data
(170086) 2002 XR14 1995-06-24 4.259 4.259 4.260 18.0 531–1714 data
(33342) 1998 WT24 2001-12-16 4.859 4.859 4.859 17.9 556–1795 data
4179 Toutatis 2004-09-29 4.031 4.031 4.031 15.3 2440–2450 data
2014 JO25 2017-04-19 4.573 4.573 4.573 17.8 582–1879 data
(137108) 1999 AN10 2027-08-07 1.014 1.010 1.019 17.9 556–1795 data
(35396) 1997 XF11 2028-10-26 2.417 2.417 2.418 16.9 881–2845 data
(154276) 2002 SY50 2071-10-30 3.415 3.412 3.418 17.6 714–1406 data
(164121) 2003 YT1 2073-04-29 4.409 4.409 4.409 16.2 1167–2267 data
(385343) 2002 LV 2076-08-04 4.184 4.183 4.185 16.6 1011–3266 data
(52768) 1998 OR2 2079-04-16 4.611 4.611 4.612 15.8 1462–4721 data
(33342) 1998 WT24 2099-12-18 4.919 4.919 4.919 17.9 556–1795 data
(85182) 1991 AQ 2130-01-27 4.140 4.139 4.141 17.1 1100 data
314082 Dryope 2186-07-16 3.709 2.996 4.786 17.5 668–2158 data
(137126) 1999 CF9 2192-08-21 4.970 4.967 4.973 18.0 531–1714 data
(290772) 2005 VC 2198-05-05 1.951 1.791 2.134 17.6 638–2061 data
(A) List includes near-Earth approaches of less than 5 lunar distances (LD) of objects with H brighter than 18.
(B) Nominal geocentric distance from the Earth's center to the object's center (Earth radius≈0.017 LD).
(C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y.
(D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD)
(E) Color codes:   unobserved at close approach   observed during close approach   upcoming approaches

Naming

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As of 2022, this minor planet has not been named.[2]

See also

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Notes

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  1. ^ The 1933 approach is better constrained than the 2105 approach as a result of the 1974, 1977, 1980 precovery images of the asteroid.[2]

References

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  1. ^ a b c d e f g h i j k l "JPL Small-Body Database Browser: 7482 (1994 PC1)" (Under "Distance Units" select km for more sig figs). Jet Propulsion Laboratory. Retrieved 12 January 2022.
  2. ^ a b c d e "7482 (1994 PC1)". Minor Planet Center. Retrieved 12 January 2022.
  3. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Cutri, R. M.; McMillan, R. S.; et al. (November 2012). "Physical Parameters of Asteroids Estimated from the WISE 3-Band Data and NEOWISE Post-Cryogenic Survey". The Astrophysical Journal Letters. 760 (1): 6. arXiv:1210.0502. Bibcode:2012ApJ...760L..12M. doi:10.1088/2041-8205/760/1/L12. S2CID 41459166.
  4. ^ a b c d e f "LCDB Data for (7482)". Asteroid Lightcurve Database (LCDB). Retrieved 2 November 2017.
  5. ^ a b Pravec, Petr; Wolf, Marek; Sarounová, Lenka (November 1998). "Lightcurves of 26 Near-Earth Asteroids". Icarus. 136 (1): 124–153. Bibcode:1998Icar..136..124P. doi:10.1006/icar.1998.5993.
  6. ^ a b Carter, Jamie (29 May 2023). "We Are (Probably) Safe From Asteroids For 1,000 Years, Say Scientists". Forbes. Retrieved 29 September 2024.
  7. ^ Fuentes-Muñoz, Oscar; Scheeres, Daniel J.; Farnocchia, Davide; Park, Ryan S. (12 June 2023). "The Hazardous km-sized NEOs of the Next Thousands of Years". The Astronomical Journal. 166 (1): 10. arXiv:2305.04896. Bibcode:2023AJ....166...10F. doi:10.3847/1538-3881/acd378. ISSN 1538-3881.
  8. ^ "Asteroid Radar History". Jet Propulsion Laboratory. Retrieved 12 January 2022.
  9. ^ a b "Horizons Batch for 2022-Jan-18 21:51 UT". JPL Horizons. Archived from the original on 13 January 2022. Retrieved 13 January 2021.
  10. ^ "Horizons Batch for 2105-Jan-18 12:28 UT". JPL Horizons. Archived from the original on 13 January 2022. Retrieved 13 January 2021.
  11. ^ "Earth Approach Jan 2022". JPL Horizons. Retrieved 5 January 2022.
  12. ^ "Moon Horizons Batch for 2022-Jan-18 18:58 UT". JPL Horizons. Archived from the original on 19 January 2022. Retrieved 19 January 2021.
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