2012 TC4
V–R = 0.41±0.02[7] | |
12.9–31[10] | |
2012 TC4 is a tumbling micro-
Approaches to large bodies
Orbital modeling shows the asteroid nominally passed about 1 million km from Earth in October 1986, but the uncertainty region suggests it could have passed as close as 20 km.[2]
Date (UT) | Object | distance in km (center–center) |
3-Σ uncertainty in km |
Speed- relative in km/s |
---|---|---|---|---|
13 October 1996 | Earth | 753 000 | ± 7000 | 6.445 |
13 October 1996 | Moon | 530 000 | ± 6300 | 7.144 |
12 October 2012 | Earth | 94 965 | ± 0.32 | 7.123 |
12 October 2012 | Moon | 113 886 | ± 0.64 | 6.773 |
12 October 2017 – 05:42 | Earth | 50 151 | ± 0.14 | 7.647 |
12 October 2017 – 19:19 | Moon | 277 697 | ± 0.34 | 6.101 |
Data from JPL 60 solution date 3 November 2017[2]
2012 Earth encounter
2012 TC4 was discovered on 4 October 2012 at apparent i-band magnitude 20.1 while the asteroid was 0.03 AU (4,500,000 km; 2,800,000 mi) from Earth.[3] It came within 0.000634 AU (0.247 LD, 94,800 km, 58,900 mi) from Earth on 12 October 2012.[2]
During the 2012 close approach, the asteroid only had an
2017 Earth encounter
On 12 October 2017 at 5:42 UT, the asteroid passed 0.00033524 AU (50,151 km; 31,163 mi) from Earth.
Paul Chodas of
The asteroid remained too faint to be recovered with automated
2012 TC4 reached a maximum apparent magnitude of 12.9 just prior to its closest approach, soon after which it came too close to the Sun to be seen with telescopes.[23] It was last observed on 14 December 2017 at an apparent magnitude of 25,[4]
Physical properties
Size reference of 2012 TC4, based on radar observations. |
Fast rotator and tumbler
Studies of the asteroid's
Radar observations
Radar images were taken from Goldstone Observatory and Green Bank Telescope on 12 October 2017. The delay-doppler images had a range resolution of 1.9 meters/pixel, the highest resolution ever obtained using Goldstone transmissions.[6][1] The images showed that 2012 TC4 was a very elongated object about 50 feet (15 meters) long and roughly 25 feet (8 meters) wide.[5] The high circular polarization ratio found for 2012 TC4 is consistent with results seen from E- and V-type NEAs previously.[6] Observations from Arecibo Observatory were planned, but had to be cancelled due to damage to the observatory as a result of Hurricane Maria.[25]
Composition
The spectrum of 2012 TC4 is that of an
2012 TC4 is composed of igneous material.[5] The short rotation period of 2012 TC4 implies that it is not a rubble pile but rather a monolithic object of non-negligible strength, which is typical for very small asteroids.[7]
Orbit change
As a result of 2012 TC4's frequent approaches to Earth, its orbit changes significantly over short periods of only decades. Its two observed close approaches and their effects are shown below:
Date | Event | Semimajor axis (AU )
|
Perihelion (AU)
|
Aphelion (AU)
|
Eccentricity | Inclination (°) | Argument of perihelion (°) | Ascending node (°) |
---|---|---|---|---|---|---|---|---|
2012-10-01 | pre-2012 approach | 1.2744 | 0.9015 | 1.6472 | 0.2926 | 1.4097 | 234.7282 | 198.5560 |
2012-10-12 | 2012 approach | 1.3837 | 0.9115 | 1.8559 | 0.3413 | 1.2320 | 228.5354 | 198.4622 |
2012-10-30 | post-2012 approach | 1.3893 | 0.9305 | 1.8480 | 0.3302 | 0.8582 | 223.1271 | 198.1033 |
2017-10-01 | pre-2017 approach | 1.4155 | 0.9410 | 1.8901 | 0.3353 | 0.8566 | 221.8553 | 198.0054 |
2017-10-12 | 2017 approach | 1.7076 | 0.9522 | 2.4630 | 0.4424 | 0.1693 | 218.4570 | 193.6520 |
2017-10-30 | post-2017 approach | 1.6492 | 0.9711 | 2.3273 | 0.4112 | 0.5327 | 248.6359 | 208.5051 |
2050-01-01 | pre-2050 approach | 1.6226 | 0.9688 | 2.2765 | 0.4030 | 0.5266 | 266.6192 | 197.8009 |
Between 2012 and 2017, 2012 TC4's average distance from the Sun increased by almost 0.4 AU, with the time it takes to orbit the sun increasing by 250 days. Its closest approach to the Sun also increased significantly, from 90% of the Earth's distance to the Sun to 97%, and its inclination lowered slightly, going from 1.4 degrees to less than 0.5 degrees relative to Earth's orbit.
As a result of non-gravitational forces such as the Yarkovsky effect on small bodies, it is difficult to constrain its orbit more than a few decades into the past or future.
See also
- List of asteroid close approaches to Earth
- List of asteroid close approaches to Earth in 2012
- List of asteroid close approaches to Earth in 2017
- NASA Planetary Defense Coordination Office
Notes
- ^ a b Lightcurve plot of 2012 TC4 at the Palmer Divide Observatory by Brian D. Warner (2012). Rotation period 0.2038±0.0002 hours with a brightness amplitude of 0.93±0.05 mag. Summary figures for 2012 TC4 at the LCDB
References
- ^ a b c "The 2012 TC4 Observing Campaign -- Radar animations". University of Maryland. Archived from the original on 7 November 2017. Retrieved 2 November 2017.
- ^ a b c d e f g h i j k l m n "JPL Small-Body Database Browser: (2012 TC4)" (2017-12-14 last obs.). Jet Propulsion Laboratory. Archived from the original on 28 November 2020. Retrieved 17 October 2017.
- ^ IAU Minor Planet Center. 7 October 2012. Retrieved 14 March 2017. (K12T04C)
- ^ a b c d "2012 TC4". Minor Planet Center. Retrieved 4 November 2017.
- ^ a b c d e "Astronomers Complete First International Asteroid Tracking Exercise". JPL. 3 November 2017. Retrieved 3 November 2017.
- ^ a b c d e f "The 2012 TC4 Observing Campaign – Radar observations UPDATE October 12, 2017". University of Maryland. Retrieved 2 November 2017.
- ^ a b c d e f g h i Ryan, William H.; Ryan, Eileen V. (2017). "Physical Characterization of NEA 2012 TC4" (PDF) (PDF). University of Maryland. Retrieved 8 March 2018.
- ^ a b c d e f "NEA 2012 TC4 -- Physical Properties". University of Maryland. Retrieved 2 November 2017.
- ^ a b c d "LCDB Data for 2012 TC4". Asteroid Lightcurve Database (LCDB). Retrieved 28 September 2017.
- ^ a b "NEODyS-2 2012TC4". Department of Mathematics, University of Pisa, Italy. Retrieved 4 November 2017.
- ^ a b "Date/Time Removed". NASA/JPL Near-Earth Object Program Office. Archived from the original on 17 October 2017. Retrieved 17 October 2017.
- ^ a b "Archive: Earth Impact Risk Summary: 2012 TC4 (7 day observation arc)". NASA/JPL Near-Earth Object Program Office. Archived from the original on 24 November 2012. Retrieved 13 March 2017.
- ^ "Horizons Batch for 2022-10-12". JPL Horizons. Retrieved 4 October 2022.
- ^ "A Very Close Encounter". www.eso.org. Retrieved 11 August 2017.
- ^ a b "Archive: Close Approach table for 2012 TC4 (using 7 day obs arc)". JPL. NASA. Archived from the original on 3 April 2013. Retrieved 22 October 2014.
- ^ a b c "Asteroid Flyby Will Benefit NASA Detection and Tracking Network". JPL. NASA. 28 July 2017. Retrieved 8 March 2018.
- ^ "TC4: HOW NASA PLANS TO TEST ITS PLANETARY DEFENSE SYSTEMS ON CLOSE-APPROACH ASTEROID". Newsweek. 6 October 2017. Retrieved 7 October 2017.
- ^ Coleman, Nancy (1 August 2017). "NASA's planetary defense system will be put to the test in October". CNN. Retrieved 2 August 2017.
- ^ "The 2012 TC4 Observing Campaign". University of Maryland. Retrieved 2 November 2017.
- ^ "NEODyS-2 Possible recovery list". Department of Mathematics, University of Pisa, Italy. Archived from the original on 14 March 2017. Retrieved 14 March 2017.
- ^ "MPEC 2017-P26 : 2012 TC4". IAU Minor Planet Center. 6 August 2017. Retrieved 6 August 2017. (K12T04C)
- ^ Math:
- ^ a b "2012TC4 Ephemerides for 12 October 2017". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 7 August 2017.
- ^ "Orbit of NEA 2012 TC4". University of Maryland. Retrieved 11 October 2017.
- ^ "Goldstone Radar Observations Planning: 2012 TC4". JPL. Retrieved 2 November 2017.
- S2CID 118549118.
External links
- Interesting Asteroids Past Earth Close encounters — Sormano Astronomical Observatory
- Image and animation of 2012 TC4 – Virtual Telescope Project
- Asteroid 2012 TC4 On Track For Close Earth Flyby AstroBob 10/3/17
- Asteroid 2012 TC4: House-Sized Asteroid Almost Hits Earth (PHOTO, VIDEO) 13 October 2012
- 2012 TC4 orbit and observations, Minor Planet Center
- 2012 TC4 at NeoDyS-2, Near Earth Objects—Dynamic Site
- 2012 TC4 at ESA–space situational awareness
- 2012 TC4 at the JPL Small-Body Database