Astroblog: iTelescope ALERT! Asteroid (6478) Gault has a tail!

Wednesday, January 09, 2019

iTelescope ALERT! Asteroid (6478) Gault has a tail!


Asteroid (6478) Gault as seen at 3:36 Local time for Mayhill, New Mexico, when it is at transit. The Comet is near nu (ν) Hydrae not far from Crater . Click to embiggen.	Asteroid (6478) Gault as seen at 4:37 Local time for SSO, Siding Spring, when it is at transit (astronomical twilight starts at 4:33). The Comet is near nu (ν) Hydrae not far from Crater . Click to embiggen.

Telescope view of Asteroid (6478) Gault. The large square is the field of View of T30 (SSO) and the small that of T17 (SSO) the medium rectangle is T5 (Mayhill). The orientation is upside down from the spotters maps.

Asteroid (6478) Gault has been reported to have a comet like tail, from CBET 4594 “The tail/trail first appears in individual ATLAS exposures on 2018 Dec. 8, as identified by Denneau, with a median combined 120-s exposure showing a tail 30" long in p.a. 290 degrees. There is no evidence of a tail in previous ATLAS imaging in January 2018. An initial analysis using a cometary Finson-Probstein model (cf. website URL http://comet-toolbox.com/FP.html, as perJ.-B. Vincent) shows that both the Dec. 2018 and Jan. 2019 data are consistent with the ejection of material or commencement of activity in early Nov. 2018”. Previous images from ATLAS and PanSTARRS show no cometary-like activity back to 2010.

It has been suggested a collision or impact is responsible for the tail. Ongoing observation of the phenomenon should be undertaken to understand its nature.

Asteroid (6478) Gault is visible from both Northern and southern scopes from with transit around 3:30 am (northernscopes) and 4:30 am (Southern scopes), however, this is just past astronomical twilight at SSO, so imaging should begin before this. The Southern scopes have the best view with the asteroid potentially visible from 12:30 am local time.

Asteroid (6478) Gault is currently magnitude 18.7, and will need long exposures on narrow field scopes with tracking for the best results.

Image of Asteroid (6478) Gault by Ulrich Eberhard Stickel using iTelesope T30, 300sec BIN2. Please do not use without his permission.

iTelescope users Ulrich Eberhard Stickel and Denis Denisenko have achieved images with T30 from SSO. Denis Denisenko's is at this link: http://scan.sai.msu.ru/~denis/Comet/6478-T30-20190108.jpg

The MPC one line ephemeris is:

06478   14.4   0.15 K194R 289.34905   83.26761  183.55769   22.81135  0.1935870  0.28161558   2.3051451  0 MPO435760  1093  19 1988-2018 0.44 M-v 38h MPC        0000   (6478) Gault              20180209

Example plan for following the asteroid, check filter availability.

;
; Single target image example, adjust filter as necessary for chosen scope. 
; 

#trackon
#count 3
#interval 300
#binning 2
#filter Red
06478   14.4   0.15 K194R 289.34905   83.26761  183.55769   22.81135  0.1935870  0.28161558   2.3051451  0 MPO435760  1093  19 1988-2018 0.44 M-v 38h MPC        0000   (6478) Gault              20180209
#shutdown

Labels: alert, asteroids, iTelescope