T3 Project

This is an international project whose main purpose is to discover possible cometary features among asteroidal population having a Tisserand parameter respect to Jupiter (Tj) less than 3.
T=3 is approximately the boundary between asteroidal and cometary orbits, according to Levison H. F., Comet Taxonomy, in Completing the Inventory of Solar System, ASP Conference Series Vol. 107, T. W. Rettig and J. M. Hahn eds. (1996).
We've presented this program at MACE 2006 in Wien, our presentation is visible here:
Presentation at MACE 2006 (PDF file, 235 kB)


First of all a complete list of suitable targets will be sent to the observers by the coordinator Luca Buzzi usually once a week. Then the observing strategy is quite simple: you have to image these minor planets (possibly only in good seeing for your location) and all the good frames collected must be normalized (bias and dark frame subtraction and possibly flat-field calibration).
Then, with Astrometrica, you have to stack all your calibrated frames according to the motion of the asteroid. If the cometary feature is not visible by visual inspection of the risulted stack, you have to measure the FWHM of the object. If this value is at least 20-25% greater than stars of similar SNR, you're probably in presence of a coma.
Please note that the SNR of the object must be at least 10, the more the better, in order to avoid false detections, always possible with the average seeing of many amateur observing sites.


Every observed object, whose cometary feature is NOT seen, must be measured in the traditional way and sent to the MPC. Information must be sent also to the coordinator with some comments about the observation.
In case a cometary feature *is seen*, before sending any message to the MPC, you have to contact the coordinator of this project, sending him the batch of the measures, together with the FWHM of the object, FWHM of the comparison stars, SNR of the object and an image.

Example of report:

COD 147
CON S. Foglia, C.Gariboldi 11, I-28100 Novara Veveri, Italy [s.foglia@libero.it]
OBS D. Crespi, S. Foglia, G. Galli, S. Minuto
MEA S. Foglia, G. Galli
TEL 0.40-m f/4 reflector + CCD
ACK 2005 SB216 possible cometary feature
COM FWHM object= 4.0" (SNR=7.6) while FWHM stars = 2.8"
K05SL6B C2005 12 29.78898 00 28 12.43 +14 26 54.0 18.9 147

Example of images:

WHAT HAPPENS IF I FOUND COMETARY FEATURE ? After that, the rule of the coordinator is to inform the other components of the project for an indipendent confirmation of cometary feature and to send a message to CBAT and MPC. The last step, once received some confirmation, is to inform some professional astronomers for the definitive confirmation.
In case of a discovery, in the IAUC will be comunicated the name of the discoverer of the cometary feature together with the names of the people who made the confirmation (on behalf of the "T3 project").
Also negative reports are very useful for planning future observations.

Example of result: IAUC 8668 for comet P/2005 SB216 (LONEOS)


Gianluca Masi - P.I. -
Luca Buzzi - "Schiaparelli Observatory" - Italy - MPC 204
Sergio Foglia - "Suno Astronomical Observatory" - Italy - MPC 147
Gianni Galli - "GiaGa Observatory" - Italy - MPC 203
Maura Tombelli - Montelupo - Italy - MPC 108
Claudio Cremaschini - Lumezzane - Italy - MPC 130
Raoul Behrend - University of Geneve-La Silla Observatory - Chile - MPC 809
Rolando Ligustri - CAST Observatory - Italy - MPC 235
Enrico Prosperi - Castelmartini - Italy - MPC 160

More informations can be found in the UAI asteroid webpage maintained by Sergio Foglia (MPC 147).