Dust Properties of Multi-Tailed Active Asteroid (6478) Gault. (arXiv:1903.09943v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Moreno_F/0/1/0/all/0/1">F. Moreno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Licandro_J/0/1/0/all/0/1">J. Licandro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jehin_E/0/1/0/all/0/1">Emmanuël Jehin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferrais_M/0/1/0/all/0/1">Marin Ferrais</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moulane_Y/0/1/0/all/0/1">Youssef Moulane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pozuelos_F/0/1/0/all/0/1">Francisco J. Pozuelos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Manfroid_J/0/1/0/all/0/1">Jean Manfroid</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Devogele_M/0/1/0/all/0/1">Maxime Devogèle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gillon_M/0/1/0/all/0/1">Michael Gillon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Benkhaldoun_Z/0/1/0/all/0/1">Zouhair Benkhaldoun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moskovitz_N/0/1/0/all/0/1">Nick Moskovitz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Popescu_M/0/1/0/all/0/1">M. Popescu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Serra_Ricart_M/0/1/0/all/0/1">M. Serra-Ricart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cabrera_Lavers_A/0/1/0/all/0/1">A. Cabrera-Lavers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Monelli_M/0/1/0/all/0/1">M. Monelli</a>
Aims. To investigate the grain properties of the dust ejected from asteroid
(6478) Gault and give insight into the activity mechanism(s).
Methods. We used a Monte Carlo dust tail brightness code to retrieve the
dates of dust ejection, the physical properties of the grains, and the total
dust mass losses during each event. The code takes into account the brightness
contribution of the asteroid itself. The model is applied to a large data set
of images spanning the period from January 11, 2019 to March 13, 2019. In
addition, both short- and long-term photometric measurements of the asteroid
have been carried out.
Results. It is shown that, to date, asteroid (6478) Gault has experienced two
episodes of impulsive dust ejection, that took place around 2018 November 5 and
2019 January 2, releasing at least 1.4$times$10$^7$ kg and 1.6 m$times$10$^6$
kg of dust, respectively, at escape speeds. The size distribution, consistent
of particles in the 1 $mu$m to 1 cm radius range, follows a broken power-law
with bending points near 15 $mu$m and 870 $mu$m. On the other hand, the
photometric series indicate a nearly constant magnitude over time, although
most likely associated to the dust envelope.
Conclusions. The dust particulates forming Gault’s tails were released from
the asteroid at escape speeds, but the specific ejection mechanism is unclear
until photometry of the dust-free asteroid are conducted, in order to asses
whether this was related to rotational disruption or to other possible causes.
Aims. To investigate the grain properties of the dust ejected from asteroid
(6478) Gault and give insight into the activity mechanism(s).
Methods. We used a Monte Carlo dust tail brightness code to retrieve the
dates of dust ejection, the physical properties of the grains, and the total
dust mass losses during each event. The code takes into account the brightness
contribution of the asteroid itself. The model is applied to a large data set
of images spanning the period from January 11, 2019 to March 13, 2019. In
addition, both short- and long-term photometric measurements of the asteroid
have been carried out.
Results. It is shown that, to date, asteroid (6478) Gault has experienced two
episodes of impulsive dust ejection, that took place around 2018 November 5 and
2019 January 2, releasing at least 1.4$times$10$^7$ kg and 1.6 m$times$10$^6$
kg of dust, respectively, at escape speeds. The size distribution, consistent
of particles in the 1 $mu$m to 1 cm radius range, follows a broken power-law
with bending points near 15 $mu$m and 870 $mu$m. On the other hand, the
photometric series indicate a nearly constant magnitude over time, although
most likely associated to the dust envelope.
Conclusions. The dust particulates forming Gault’s tails were released from
the asteroid at escape speeds, but the specific ejection mechanism is unclear
until photometry of the dust-free asteroid are conducted, in order to asses
whether this was related to rotational disruption or to other possible causes.
http://arxiv.org/icons/sfx.gif
