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TOPIC: Asteroid 3200 Phaethon (1983 TB)


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Asteroid (3200) Phaethon
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Asteroid (3200) Phaethon reaches magnitude +10.7 at 20:10 UT, 14th December 2017



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Asteroid (3200) Phaethon is at Opposition in the constellation Auriga on the 11th December 2017.

Magnitude: 11.3 V
Distance to Earth: 0.124 AU (48.2 lunar distances)
Distance to Sun: 1.100 AU



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Title: Resurrection of (3200) Phaethon in 2016
Author: Man-To Hui, Jing Li

We present a study of the active asteroid (3200) Phaethon in the 2016 apparition using the STEREO spacecraft and compare the results with data from the previous two perihelia in 2009 and 2012. Once again, Phaethon brightened by ~2 mag soon after its perihelion passage, contradicting expectations from the phase function of a macroscopic monolithic body. Subsequently, a short antisolar tail of ~0.1 in length was formed within ~1 day and quickly disappeared. No trail was seen. Our syndyne-synchrone analysis indicates that the tail was comprised of submicron to micron particles and can be approximated by a synchrone coinciding with the outburst. We estimate that the outburst has released a mass of ~10^4--10^5 kg, comparable to the two mass ejections in 2009 and 2012, and that the average mass-loss rate is ~0.1--1 kg s^-1. The forward-scattering effect hinted at low level activity of Phaethon prior to the outburst, which increased the effective cross section by merely \lesssim 1 km^2. Without the forward-scattering enhancement, detecting such activity at side-scattering phase angles is very difficult. The forward-scattering effect also reinforces that the ejected dust grains rather than gas emissions were responsible for the activity of Phaethon. Despite Phaethon's reactivation, it is highly unlikely that the Geminid meteoroid stream can be sustained by similar perihelion mass-loss events.

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RE: Asteroid 3200 Phaethon (1983 TB)
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Asteroid 3200 Phaethon makes a close approach to the Earth (0.402 au) at 00:13 UT, 29th September 2016.



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Asteroid 3200 Phaethon (1983 TB) makes its closest approach to the Earth (0.796 AU) on the 8th March 2015

Ephemeris

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     Mag
2015 03 05    00 30 51.7 -02 30 03   0.8059  0.3995    22.8   105.7    16.1
2015 03 06    00 26 20.1 -03 10 05   0.8016  0.3717    20.6   109.9    16.1
2015 03 07    00 21 12.9 -03 51 37   0.7983  0.3432    18.3   114.7    16.3
2015 03 08    00 15 25.4 -04 34 16   0.7964  0.3142    15.9   120.2    16.5
2015 03 09    00 08 52.8 -05 17 20   0.7964  0.2847    13.3   126.5    16.8
2015 03 10    00 01 31.1 -05 59 35   0.7992  0.2550    10.7   133.8    17.3
2015 03 11    23 53 18.7 -06 38 53   0.8058  0.2255     8.0   142.0    18.0
2015 03 12    23 44 20.3 -07 11 45   0.8181  0.1970     5.7   149.9    19.0
2015 03 13    23 34 54.0 -07 32 42   0.8380  0.1713     4.5   153.1    19.4
2015 03 14    23 25 43.7 -07 34 07   0.8679  0.1512     5.2   143.8    17.6
2015 03 15    23 18 05.1 -07 08 39   0.9089  0.1408     6.7   123.9    15.3
2015 03 16    23 13 16.3 -06 15 25   0.9584  0.1431     8.1   100.5    13.9
2015 03 17    23 11 38.2 -05 03 12   1.0109  0.1574     9.0    79.7    13.4
2015 03 18    23 12 29.1 -03 43 36   1.0617  0.1799     9.3    63.7    13.3
2015 03 19    23 14 53.4 -02 24 09   1.1090  0.2068     9.4    52.1    13.3
2015 03 20    23 18 10.6 -01 08 10   1.1525  0.2357     9.4    43.8    13.5
2015 03 21    23 21 56.2 +00 03 19   1.1927  0.2654     9.4    37.7    13.6
2015 03 22    23 25 56.1 +01 10 15   1.2301  0.2951     9.3    33.2    13.8
2015 03 23    23 30 02.2 +02 12 54   1.2652  0.3244     9.3    29.7    14.0
2015 03 24    23 34 09.9 +03 11 41   1.2983  0.3532     9.3    27.1    14.1
2015 03 25    23 38 16.5 +04 06 57   1.3298  0.3815     9.3    25.0    14.3
2015 03 26    23 42 20.4 +04 59 06   1.3599  0.4091     9.3    23.3    14.4
2015 03 27    23 46 20.7 +05 48 24   1.3888  0.4361     9.4    21.9    14.6
2015 03 28    23 50 16.9 +06 35 09   1.4167  0.4625     9.5    20.8    14.7
2015 03 29    23 54 08.7 +07 19 36   1.4436  0.4883     9.6    19.8    14.8
2015 03 30    23 57 56.0 +08 01 57   1.4697  0.5135     9.7    19.1    15.0
2015 03 31    00 01 38.9 +08 42 22   1.4950  0.5382     9.8    18.4    15.1


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RE: Asteroid 3200 Phaethon (1983 TB)
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Asteroid 3200 Phaethon makes its closest approach to the Earth (0.642 AU) on the 2nd November 2013



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Asteroid (3200) Phaethon, at mag 16.7, will pass 0.56 from Mars at 23:00 UT, 1st September 2013.

Ephemeris

Date             UT      R.A. (J2000) Decl.         Delta     r         El.    Ph.     Mag
2013 08 31 000000 08 11 25.0 +20 46 30   1.581   0.986   37.1  38.1  17.1
2013 09 01 000000 08 15 56.8 +20 24 19   1.562   0.969   36.9  38.8  17.0
2013 09 02 000000 08 20 34.1 +20 01 07   1.544   0.952   36.8  39.4  17.0
2013 09 03 000000 08 25 16.9 +19 36 53   1.525   0.934   36.6  40.0  17.0
2013 09 04 000000 08 30 05.4 +19 11 34   1.507   0.916   36.3  40.7  16.9
2013 09 05 000000 08 34 59.9 +18 45 07   1.489   0.898   36.1  41.4  16.9
2013 09 06 000000 08 40 00.7 +18 17 29   1.472   0.880   35.8  42.0  16.8


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Title: The Dust Tail of Asteroid (3200) Phaethon
Authors: David Jewitt, Jing Li, Jessica Agarwal

We report the discovery of a comet-like tail on asteroid (3200) Phaethon when imaged at optical wavelengths near perihelion. In both 2009 and 2012, the tail appears >=350" (2.5x10^8 m) in length and extends approximately in the projected anti-solar direction. We interpret the tail as being caused by dust particles accelerated by solar radiation pressure. The sudden appearance and the morphology of the tail indicate that the dust particles are small, with an effective radius ~1 micrometer and a combined mass ~3x10^5 kg. These particles are likely products of thermal fracture and/or desiccation cracking under the very high surface temperatures (~1000 K) experienced by Phaethon at perihelion. The existence of the tail confirms earlier inferences about activity in this body based on the detection of anomalous brightening. Phaethon, the presumed source of the Geminid meteoroids, is still active.

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Title: Recurrent Perihelion Activity in (3200) Phaethon
Authors: Jing Li, David Jewitt

We present a study of planet-crossing asteroid (3200) Phaethon at three successive perihelia in 2009, 2010 and 2012, using the NASA STEREO spacecraft. Phaethon is clearly detected in 2009 and 2012, but not in 2010. In both former years, Phaethon brightened unexpectedly by ~1 magnitude at large phase angles, inconsistent with the ~1 magnitude of steady fading expected from a discrete, macroscopic body over the same phase angle range. With a perihelion distance of 0.14 AU and surface temperatures up to ~1000 K, a thermal origin of this anomalous brightening is strongly suspected. However, simple thermal emission from Phaethon is too weak, by a factor >1000, to explain the brightening. Neither can ice survive on this body, ruling out comet-like sublimation. Our preferred explanation is that brightening occurs as a result of dust produced and ejected from Phaethon, perhaps by thermal fracture and/or thermal decomposition of surface minerals when near perihelion. A contribution from prompt emission by oxygen released by desiccation of surface minerals cannot be excluded. We infer an ejected mass of order 4x10^8 a_mm kg per outburst, where a_mm is the mean dust radius in millimetres. For plausible dust radii, this mass is small compared to the estimated mass of Phaethon (~2x10^14 kg) and to the mass of the Geminid stream (10^12 kg to 10^13 kg) with which Phaethon is dynamically associated. Perihelion mass-loss events like those observed in 2009 and 2012 contribute to, but do not necessarily account for the Geminids stream mass.

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