astro.wikisort.org - Asteroid

(433953) 1997 XR₂ is a sub-kilometer sized asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It was discovered on 4 December 1997, by the Lincoln Near-Earth Asteroid Research (LINEAR) program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States.[2]

(433953) 1997 XR₂

Discovery[1]
Discovered by	LINEAR
Discovery site	Lincoln Lab's ETS
Discovery date	4 December 1997
Designations
MPC designation	(433953) 1997 XR2
Alternative designations	1997 XR2
Minor planet category	Apollo · NEO · PHA[1][2]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	19.20 yr (7,014 days)
Aphelion	1.2924 AU
Perihelion	0.8601 AU
Semi-major axis	1.0762 AU
Eccentricity	0.2008
Orbital period (sidereal)	1.12 yr (408 days)
Mean anomaly	316.19°
Mean motion	0° 52m 58.08s / day
Inclination	7.1919°
Longitude of ascending node	250.69°
Argument of perihelion	84.604°
Earth MOID	0.000135 AU · 0.05 LD
Physical characteristics
Mean diameter	0.2 km (generic)[3] 0.23 km[4]
Mass	1.7×1010 kg[4]
Absolute magnitude (H)	20.8[1]

Orbit and classification

The asteroid orbits the Sun at a distance of 0.9–1.3 AU once every 13 months (408 days). Its orbit has an eccentricity of 0.20 and an inclination of 7° with respect to the ecliptic.

It has an Earth minimum orbital intersection distance of 0.000135 AU, which corresponds to 0.05 lunar distances.[1] The body's observation arc begins with its official discovery observation, as no precoveries were taken, and no prior identifications were made.[2]

Impact risk

Between 2002 and 2006, 1997 XR₂ was considered to have about a 1 in 10,000 chance of colliding with Earth on 1 June 2101, based on a 27-day observation arc following its discovery.[4] With an estimated mass of 1.7×10¹⁰ kilograms, it was ranked at level 1 on the Torino scale (0–10) of impact risk, and was the only near-Earth object to be ranked higher than zero until it was joined by 2004 VD17 at level 1 in November 2004, and then when 99942 Apophis – then known only by its provisional designation 2004 MN₄ – was temporarily assessed at level four in December 2004. Both 2004 VD17 and 99942 Apophis are now rated at level zero.

Recovery

On 24 February 2006, 1997 XR₂ was observed by the Mount Lemmon Survey after being lost for more than 8 years.[2] The refinement of its orbit eliminated the possibility of impact in 2101. It is now known that on 20 November 2101, the asteroid will be 0.0392 AU (5,860,000 km) from Earth.[5]

Physical characteristics

According to a generic conversion of absolute magnitude to diameter, 1997 XR₂ measures 200 to 230 meters.[3][4]

Naming

As of 2017, this minor planet remains unnamed.[2]

References

External links

• Earth Impact Risk Ratings Posted in the Last 31 Days Archived 5 October 2007 at the Wayback Machine, A/CC's Consolidated Risk Tables
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• (433953) 1997 XR2 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• (433953) 1997 XR2 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical Properties · Summary
• (433953) 1997 XR2 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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