2004 TN1

2004 TN1 is a sub-kilometer near-Earth asteroid and potentially hazardous object of the Apollo group, approximately 180 meters (600 ft) in diameter. It was first observed by the Near-Earth Asteroid Tracking at Palomar Observatory on 5 October 2004. The asteroid has a notably low sub-lunar Earth-MOID of 0.38 LD. As of 2019, it has only been observed in Fall 2004.[1][2]

2004 TN1
Discovery [1][2]
Discovered byNEAT
Discovery sitePalomar Obs.
Discovery date5 October 2004
(first observed only)
Designations
2004 TN1
Apollo · NEO · PHA [1][2]
Orbital characteristics [2]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 6 · 5[1]
Observation arc30 days
Aphelion4.6652 AU
Perihelion0.8304 AU
2.7478 AU
Eccentricity0.6978
4.55 yr (1,664 d)
52.982°
0° 12m 59.04s / day
Inclination8.4407°
213.96°
233.55°
Earth MOID0.0010 AU (0.38 LD)
(151000 km)
Jupiter MOID0.8187 AU
TJupiter2.9230
Physical characteristics
Mean diameter
0.13 km (est. at 0.20)[3]
0.24 km (est. at 0.057)[3]
21.8[1][2]

    Orbit and classification

    2004 TN1 is a member of the Apollo group of asteroids, which are Earth-crossing asteroids. They are the largest group of near-Earth objects with approximately 10 thousand known members. It orbits the Sun at a distance of 0.8–4.7 AU once every 4 years and 7 months (1,664 days; semi-major axis of 2.75 AU). Its orbit has an eccentricity of 0.70 and an inclination of 8° with respect to the ecliptic.[2] Due to its highly eccentric orbit it also crosses the orbit of Mars at 1.66 AU. The body's observation arc begins with its first observation at Palomar on 5 October 2004.[1]

    However, its orbit is poorly determined, with observations taken over a few weeks in 2004, yielding an orbital certainty of 5 and 6, respectively, with 0 being a well-determined orbit and 9 being an extremely poorly determined orbit. More observations are needed to improve the precision of the asteroid's orbital parameters to determine its potentially hazard it may pose to Earth in the distant future.[1][2]

    Close approaches

    The asteroid has an Earth minimum orbital intersection distance of 0.00100677 AU (151,000 km; 93,600 mi), which corresponds to 0.38 lunar distances and makes it a potentially hazardous asteroid due to its sufficiently large size.[2] On 24 November 2004, it passed Earth at a nominal distance of 0.0935379 AU (14,000,000 km; 8,690,000 mi).[2] It has the fourth smallest geocentric Minimum Orbital Intersection Distance of any asteroid, after 2008 TC3 which exploded in Earth's atmosphere in 2008, 1994 GV, and 2014 AA which also impacted the Earth in 2014. The asteroid, however, will not make any significant close approaches to Earth in at least the next century, as it is expected to pass close to Earth again on 8 October 2114.[2]

    Numbering and naming

    This minor planet has neither been numbered nor named by the Minor Planet Center, which requires repeated observations on more than one opposition.[1]

    Physical characteristics

    2004 TN1 has an unknown spectral type and could be of siliceous (S-type) or carbonaceous (C-type) composition with high or low albedo, respectively.[2][4]

    Rotation period

    As of 2019, no rotational lightcurve of this asteroid has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[2][4]

    Diameter and albedo

    Based on an magnitude-to-diameter conversion and a measured absolute magnitude of 21.8, 2004 TN1 measures between 130 and 240 meters in diameter for an assumed geometric albedo of 0.20 (siliceous) and 0.057 (carbonaceous), respectively.[1][3] A theoretical impact into porous rock at 45°, assuming the asteroid to have a density of 2 g/cm3, would yield a crater between 1.7 and 3.2 kilometers wide, slightly larger than Meteor Crater in Arizona.[5]

    References
    1. "2004 TN1". Minor Planet Center. Retrieved 29 November 2019.
    2. "JPL Small-Body Database Browser: (2004 TN1)" (2004-11-04 last obs.). Jet Propulsion Laboratory. Retrieved 29 November 2019.
    3. "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 29 November 2019.
    4. "Asteroid 2004 TN1". Small Bodies Data Ferret. Retrieved 29 November 2019.
    5. Melosh, H. J.; Bey, Ross A. "Crater size from projectile diameter". www.lpl.arizona.edu. Archived from the original on 17 November 2014. Retrieved 1 November 2014.

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