2014 XL7

2014 XL7 (also written 2014 XL7) was the most dangerous potentially hazardous asteroid discovered in 2014 that remained on the Sentry Risk Table at the end of 2014.[5] The Apollo near-Earth asteroid is estimated to be roughly 230 meters in diameter and had a cumulative 1 in 83000 chance of impacting Earth on 4–5 June between the years 2048 and 2084.[3] It was removed from the Sentry Risk Table on 15 January 2015 using JPL solution 9 with an observation arc of 35 days.[6]

2014 XL7
Discovery[1]
Discovered byMt. Lemmon Survey
Discovery date11 December 2014
Designations
2014 XL7
Orbital characteristics[2]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 3
Observation arc475 days (1.30 yr)
Aphelion2.5362 AU (379.41 Gm) (Q)
Perihelion0.77211 AU (115.506 Gm) (q)
1.6542 AU (247.46 Gm) (a)
Eccentricity0.53323 (e)
2.13 yr (777.08 d)
235.20° (M)
0° 27m 47.772s / day (n)
Inclination7.5012° (i)
74.514° (Ω)
250.71° (ω)
Earth MOID0.00258894 AU (387,300 km)
Jupiter MOID2.83909 AU (424.722 Gm)
Physical characteristics
Dimensions
  • ~230 meters[3]
  • 170–380 meters[4]
21.0[2]

    Description

    On 1 September 2014 the asteroid passed about 0.259 AU (38,700,000 km; 24,100,000 mi) from Earth,[7] but at that time the asteroid had an apparent magnitude of 25 and was roughly 25 degrees from the Sun.[8] It was discovered on 11 December 2014 by the Mount Lemmon Survey at an apparent magnitude of 20 using a 1.5-meter (59 in) reflecting telescope.[1] The asteroid has an observation arc of 35 days with an uncertainty parameter of 6.[2] The asteroid was last observed on 15 January 2015,[2] and is still being actively observed to better constrain the orbit. The asteroid will not drop below magnitude 25 until March 2015.[9]

    With an absolute magnitude of 21,[2] the asteroid is about 170–380 meters in diameter.[4]

    With an observation arc of 19 days, it had a cumulative Palermo Scale rating of –2.85 and was briefly the 9th most dangerous asteroid known.[5] It was calculated that on 4 June 2065 there was a 1 in 270000 chance of impact and on 4 June 2076 there was a 1 in 137000 chance of impact.[3] On 15 January 2015 the asteroid was recovered by Cerro Paranal Observatory which extended the observation arc to 35 days,[10] and 2014 XL7 was removed from the Sentry Risk Table.[6]

    References
    1. "MPEC 2014-X76 : 2014 XL7". IAU Minor Planet Center. 15 December 2014. Retrieved 1 January 2015. (K14X07L)
    2. "JPL Small-Body Database Browser: (2014 XL7)" (last observation: 2014-12-30; arc: 19 days). Jet Propulsion Laboratory. Retrieved 4 April 2016.
    3. "Earth Impact Risk Summary: 2014 XL7". WayBack Machine: NASA/JPL Near-Earth Object Program Office. 31 December 2014. Archived from the original on 31 December 2014. Retrieved 1 January 2015.
    4. "Absolute Magnitude (H)". NASA/JPL. Retrieved 1 January 2015.
    5. "Sentry Risk Table". WayBack Machine: NASA/JPL Near-Earth Object Program Office. 31 December 2014. Archived from the original on 31 December 2014. Retrieved 1 January 2015. (PS=–2.85)
    6. "Date/Time Removed". NASA/JPL Near-Earth Object Program Office. Retrieved 16 January 2015.
    7. "JPL Close-Approach Data: (2014 XL7)" (last observation: 2014-12-30; arc: 19 days). Retrieved 1 January 2015.
    8. "2014XL7 Ephemerides for 1 September 2014". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 1 January 2015.
    9. "2014XL7 Ephemerides for 1 January 2015 through 1 April 2015". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 12 December 2014.
    10. "2014 XL7 Orbit". IAU Minor Planet Center. Retrieved 16 January 2015.


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