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Post Info TOPIC: Comet P/2010 A2 (LINEAR)


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Asteroid P/2010 A2
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Title: New observational evidence of active asteroid P/2010 A2: Slow rotation of the largest fragment
Author: Yoonyoung Kim, Masateru Ishiguro, Myung Gyoon Lee

We report new observations of the active asteroid P/2010 A2 taken when it made its closest approach to the Earth (1.06 au in 2017 January) after its first discovery in 2010. Despite a crucial role of the rotational period in clarifying its ejection mechanism, the rotational property of P/2010 A2 has not yet been studied due to the extreme faintness of this tiny object (~120 m in diameter). Taking advantage of the best observing geometry since the discovery, we succeed in obtaining the rotational light curve of the largest fragment with Gemini/GMOS-N. We find that (1) the largest fragment has a double-peaked period of 11.36±0.02 hr spinning much slower than its critical spin period; (2) the largest fragment is a highly elongated object (a/b \geqslant 1.94) with an effective radius of 61.9^{+16.8}_{-9.2} m; (3) the size distribution of the ejecta follows a broken power law (the power indices of the cumulative size distributions of the dust and fragments are 2.5±0.1 and 5.2±0.1, respectively); (4) the mass ratio of the largest fragment to the total ejecta is around 0.8; and (5) the dust cloud morphology is in agreement with the anisotropic ejection model in Kim et al. (2017). These new characteristics of the ejecta obtained in this work are favourable to the impact shattering hypothesis.

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RE: Comet P/2010 A2 (LINEAR)
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Comet P/2010 A2 (LINEAR) makes its closest approach to the Earth (1.480 AU) in the constellation Capricornus on the 8th August 2015 



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Comet P/2010 A2 (LINEAR) is at Opposition (1.482 AU) in the constellation Capricornus on the 5th August 2015 

Ephemeris

Date    TT    R. A. (2000) Decl.     Delta      r    Elong.  Phase   Mag
2015 08 01    21 05 08.3 -18 06 49   1.4873  2.4997   174.7     2.2  20.3
2015 08 02    21 04 04.4 -18 09 11   1.4855  2.4988   175.8     1.7  20.3
2015 08 03    21 03 00.1 -18 11 31   1.4840  2.4979   177.0     1.2  20.3
2015 08 04    21 01 55.6 -18 13 50   1.4827  2.4970   178.0     0.8  20.3
2015 08 05    21 00 50.8 -18 16 08   1.4817  2.4961   178.7     0.5  20.3
2015 08 06    20 59 45.9 -18 18 24   1.4810  2.4952   178.5     0.6  20.3
2015 08 07    20 58 41.0 -18 20 37   1.4806  2.4943   177.6     1.0  20.3
2015 08 08    20 57 36.0 -18 22 48   1.4804  2.4934   176.5     1.4  20.3
2015 08 09    20 56 31.1 -18 24 57   1.4805  2.4925   175.3     1.9  20.3
2015 08 10    20 55 26.4 -18 27 02   1.4809  2.4915   174.1     2.4  20.3
2015 08 11    20 54 21.9 -18 29 05   1.4815  2.4906   173.0     2.9  20.3
2015 08 12    20 53 17.8 -18 31 04   1.4824  2.4897   171.8     3.3  20.3
2015 08 13    20 52 14.0 -18 33 00   1.4836  2.4888   170.6     3.8  20.3
2015 08 14    20 51 10.8 -18 34 52   1.4851  2.4878   169.4     4.3  20.3
2015 08 15    20 50 08.1 -18 36 39   1.4868  2.4869   168.2     4.8  20.3
2015 08 16    20 49 06.0 -18 38 23   1.4888  2.4859   167.0     5.3  20.3
2015 08 17    20 48 04.7 -18 40 03   1.4910  2.4850   165.8     5.8  20.3
2015 08 18    20 47 04.2 -18 41 37   1.4935  2.4840   164.6     6.2  20.3
2015 08 19    20 46 04.5 -18 43 08   1.4962  2.4830   163.4     6.7  20.3
2015 08 20    20 45 05.8 -18 44 33   1.4992  2.4821   162.2     7.2  20.3
2015 08 21    20 44 08.1 -18 45 54   1.5025  2.4811   161.0     7.6  20.3
2015 08 22    20 43 11.4 -18 47 09   1.5060  2.4801   159.8     8.1  20.3
2015 08 23    20 42 15.9 -18 48 20   1.5098  2.4792   158.6     8.5  20.3
2015 08 24    20 41 21.6 -18 49 25   1.5138  2.4782   157.5     9.0  20.3
2015 08 25    20 40 28.5 -18 50 25   1.5180  2.4772   156.3     9.4  20.3
2015 08 26    20 39 36.7 -18 51 20   1.5225  2.4762   155.1     9.9  20.4
2015 08 27    20 38 46.3 -18 52 09   1.5272  2.4752   154.0    10.3  20.4
2015 08 28    20 37 57.2 -18 52 53   1.5321  2.4742   152.8    10.8  20.4
2015 08 29    20 37 09.6 -18 53 32   1.5373  2.4732   151.7    11.2  20.4
2015 08 30    20 36 23.5 -18 54 05   1.5427  2.4722   150.5    11.6  20.4
2015 08 31    20 35 38.9 -18 54 33   1.5483  2.4712   149.4    12.0  20.4


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Comet P/2010 A2 (LINEAR) is at Opposition (1.335 AU) on the 8th April 2014 



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Comet P/2010 A2 (LINEAR) makes its closest approach to the Earth (1.334 AU) on the 4th April 2014

Ephemeris

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   Mag
2014 04 01    13 03 40.9 -15 01 32   1.3352  2.3216   167.9     5.2  19.8
2014 04 02    13 02 38.9 -14 57 26   1.3344  2.3230   168.8     4.8  19.8
2014 04 03    13 01 36.7 -14 53 11   1.3340  2.3244   169.7     4.4  19.8
2014 04 04    13 00 34.3 -14 48 49   1.3337  2.3258   170.4     4.1  19.8
2014 04 05    12 59 31.8 -14 44 18   1.3338  2.3272   171.1     3.8  19.8
2014 04 06    12 58 29.3 -14 39 40   1.3341  2.3285   171.6     3.6  19.8
2014 04 07    12 57 27.0 -14 34 55   1.3347  2.3299   172.0     3.4  19.8
2014 04 08    12 56 24.8 -14 30 03   1.3355  2.3313   172.2     3.4  19.8
2014 04 09    12 55 22.9 -14 25 06   1.3366  2.3327   172.1     3.4  19.8
2014 04 10    12 54 21.4 -14 20 03   1.3380  2.3341   172.0     3.4  19.8
2014 04 11    12 53 20.2 -14 14 55   1.3396  2.3354   171.6     3.6  19.8
2014 04 12    12 52 19.6 -14 09 42   1.3416  2.3368   171.0     3.8  19.8
2014 04 13    12 51 19.6 -14 04 26   1.3437  2.3382   170.4     4.1  19.8
2014 04 14    12 50 20.3 -13 59 06   1.3462  2.3395   169.6     4.4  19.8
2014 04 15    12 49 21.7 -13 53 43   1.3488  2.3409   168.8     4.8  19.8
2014 04 16    12 48 23.8 -13 48 18   1.3518  2.3423   167.9     5.2  19.9
2014 04 17    12 47 26.9 -13 42 51   1.3550  2.3436   166.9     5.6  19.9
2014 04 18    12 46 30.9 -13 37 22   1.3585  2.3450   165.9     6.0  19.9
2014 04 19    12 45 35.9 -13 31 53   1.3622  2.3464   164.9     6.4  19.9
2014 04 20    12 44 41.9 -13 26 23   1.3662  2.3477   163.9     6.8  19.9
2014 04 21    12 43 49.1 -13 20 53   1.3704  2.3491   162.8     7.3  19.9
2014 04 22    12 42 57.4 -13 15 24   1.3748  2.3504   161.7     7.7  19.9
2014 04 23    12 42 07.0 -13 09 56   1.3796  2.3518   160.6     8.1  19.9
2014 04 24    12 41 17.8 -13 04 29   1.3845  2.3531   159.5     8.6  19.9
2014 04 25    12 40 30.0 -12 59 05   1.3897  2.3545   158.4     9.0  19.9
2014 04 26    12 39 43.6 -12 53 43   1.3952  2.3558   157.3     9.5  19.9
2014 04 27    12 38 58.6 -12 48 24   1.4009  2.3572   156.2     9.9  20.0
2014 04 28    12 38 15.1 -12 43 09   1.4068  2.3585   155.1    10.3  20.0
2014 04 29    12 37 33.2 -12 37 57   1.4129  2.3598   154.0    10.8  20.0
2014 04 30    12 36 52.8 -12 32 50   1.4193  2.3612   152.9    11.2  20.0


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Strange asteroid has a tail 1 million kilometers long

An odd asteroid's peculiar tail is far longer than previously thought, stretching nearly three times the distance from Earth to the moon, scientists say.
The surprising tail of dust streaming from the asteroid P/2010 A2 is about 1 million kilometers long, new photos taken by the One Degree Imager (ODI) camera at the WIYN telescope in Arizona reveal.

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Comet P/2010 A2 (LINEAR) is at Perihelion (2.004 AU) on the 22nd May, 2013.

Ephemeris

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   Mag
2013 05 21    05 23 12.4 +25 51 24   2.9067  2.0040    21.9    10.9  20.8
2013 05 22    05 25 41.5 +25 52 18   2.9108  2.0040    21.5    10.7  20.8
2013 05 23    05 28 10.7 +25 53 04   2.9147  2.0040    21.1    10.5  20.8
2013 05 24    05 30 40.0 +25 53 41   2.9186  2.0040    20.7    10.3  20.8
2013 05 25    05 33 09.4 +25 54 09   2.9225  2.0041    20.3    10.1  20.8
2013 05 26    05 35 38.8 +25 54 29   2.9262  2.0041    19.9     9.9  20.9
2013 05 27    05 38 08.4 +25 54 40   2.9300  2.0041    19.6     9.7  20.9
2013 05 28    05 40 37.9 +25 54 43   2.9336  2.0042    19.2     9.5  20.9
2013 05 29    05 43 07.6 +25 54 37   2.9372  2.0042    18.8     9.4  20.9
2013 05 30    05 45 37.2 +25 54 22   2.9407  2.0043    18.4     9.2  20.9
2013 05 31    05 48 07.0 +25 53 58   2.9442  2.0043    18.0     9.0  20.9


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Title: Dynamics of Large Fragments in the Tail of Active Asteroid P/2010 A2
Authors: Jessica Agarwal, David Jewitt, Harold Weaver

We examine the motions of large fragments at the head of the dust tail of active asteroid P/2010 A2. In previous work we showed that these fragments were ejected from the primary nucleus in early 2009, either following a hypervelocity impact or by rotationally induced break-up. Here, we follow their positions through a series of Hubble Space Telescope images taken during the first half of 2010. The orbital evolution of each fragment allows us to constrain its velocity relative to the main nucleus after leaving its sphere of gravitational influence. We find that the fragments constituting a prominent X-shaped tail feature were emitted in a direction opposite to the motion of the asteroid and towards the south of its orbital plane. Derived emission velocities of these primary fragments range between 0.02 and 0.3 m/s, comparable to the ~0.08 m/s gravitational escape speed from the nucleus. Their sizes are on the order of decimeters or larger. We obtain the best fits to our data with ejection velocity vectors lying in a plane that includes the nucleus. This may suggest that the cause of the disruption of P/2010 A2 is rotational break-up.

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Suspected Asteroid-to-asteroid Collision

Astronomers photographed a suspected asteroid-to-asteroid collision for the first time. This time-lapse video of Hubble telescope images shows the smashed-up remnants in the Asteroid Belt thinning out over the course of 5 months.



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Comet P/2010 A2 (LINEAR) makes its closest approach to the Earth (1.203 AU) on the 12th October, 2012.



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