Asteroid
2015 HQ11 passed by the Earth at a distance of 490 100 km (1.27 times
the average distance between the Earth and the Moon, or 0.33% of the
average distance between the Earth and the Sun), slightly before 6.20 am
GMT on Saturday 25 April 2015. There was no danger of the asteroid
hitting us, though had it done so it would have presented only a minor
threat. 2015 HQ11 has an estimated equivalent diameter of 7-23 m (i.e.
it is estimated that a spherical object with the same volume would be 7-23 m in diameter), and an object of this size would be expected to
explode in an airburst (an explosion caused by superheating from
friction with the Earth's atmosphere, which is greater than that caused
by simply falling, due to the orbital momentum of the asteroid) in the
atmosphere between 37 and 20 km above the ground, with only fragmentary
material reaching the Earth's surface.
Image of 2015 HQ11 taken on 25 April 2015 from Ceccano in Italy. The asteroid is the point indicated by the two lines at right angles in the center of the picture. The longer lines are stars, their elongation being caused by the telescope traking the asteroid over the length of the exposure, in this case 150 seconds. Gianluca Masi/Virtual Telescope.
2015 HQ11 was discovered on 23 April 2015 (two days before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey,
which is located in the Catalina Mountains north of Tucson. The
designation 2015 HQ11 implies that it was the 291st asteroid (asteroid Q11 ) discovered in the secondt half of April 2015 (period 2015 H).
The calculated orbit of 2015 HQ11. JPL Small Body Database.
2015 HQ11 has
an 673 day orbital period and an eccentric orbit tilted at an angle of 8.21° to the plane of the Solar System, which takes it from 0.91 AU from
the Sun (i.e. 91% of the average distance at which the Earth orbits
the Sun) to 2.09 AU from the Sun (i.e. 209% of the average distance at
which the Earth orbits the Sun, somewhat greater than the distance at
which the planet Mars orbits the Sun). It is therefore classed as an
Apollo Group Asteroid (an asteroid that is on average further from the
Sun than the Earth, but which does get closer). This also means that
close encounters between 2015 HQ11 and the Earth are quite common, with
the last having occurred in March 2004 next predicted for September
this year.
See also...
Asteroid
2015 HH passed by the Earth at a distance of 4 513 000 km (11.7 times
the average distance between the Earth and the Moon, or 3.02% of the
average distance between the Earth and the Sun), slightly after 10.25 am
GMT on Tuesday 14 April 2015. There was...
Lyrid Meteor Shower to peak on 22-23 April this year. The
Lyrid Meteors will be at peak visibility between 22 and 23 April this
year, shortly after the New Moon on 19 April, which should ensure a good
display in areas with clear skies. The meteors, which appear to radiate...
Asteroid 2015 FL passes the Earth. Asteroid 2015 FL passed by the Earth at a distance of 7 597
000 km (19.8 times the average distance between the Earth and the Moon,
or 5.08 % of the average distance between the Earth and the Sun), at about 0.50 am GMT on Saturday 11 April 2015. There was...
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