MONET PHYSICAL

CHARACTERISTICS OF MAIN BELT COMETS

Vidojevica 2011Ivan Milić

Andrej ObuljenStanislav Milošević

Main Belt

The asteroid belt (main belt) is the region of the Solar System located between the orbits of the planets Mars and Jupiter

A small group of objects with orbits close to the main asteroid belt are displaying cometary activity

Main Belt

Main Belt Comets

Comets originally come from the outer solar system

Main belt comets are objects from asteroid belt, which are displaying cometary activity

The origin of their cometary activity is not fully explained

Comets and asteroids

Comets - a small body in the Solar System that is found to display a diffuse developing coma and that contains a monolithic nucleus consisting of ice and dust grains

Asteroids – solid rock Comets-elongated orbits ; asteroids-

near-circular orbits Some intermediate objects – properties

that are typical of both categories.

On August 7, 1996 Eric W. Elst discovered intermediate object that showed a cometary tail and was designated as 133P/Elst-Pizarro, while moving in a typical asteroidal orbit in the MBA.

This was the first known “Main Belt Comet”

There are seven objects classified as a Main Belt Comets:

1. 133P/Elst-Pizarro 2. 176P/Linear 3. 238P/Read (P/2005 U1) 4. P/2008 R1 (Garradd) 5. P/2010 A2 (Linear) 6. P/2010 R2 (La Sagra) 7. 596 Scheila

Our high priority objecrs are: 176P/Linear,

238P/Read (P/2005 U1), P/2010 R2 (La Sagra)

La Sagra is of special interest since it is recently descovered object with only a small amount of collected data

Goals:

Collect photometrical data of Main Belt Comets

Study their physical characteristics Rotational periods Colors

First part of the project was a broad-band color study of these objects

By imaging in three different filters we will be able to construct color diagrams

Filters are: 1. R (660 nm) 2. V (550 nm)

Filter Name Description CentralWavelength

[nm]

FWHM

[nm]

Peak

Wavelength

[nm]

T_max

[%]

none no filter (CCD) (CCD) (CCD) (CCD)

clear BG glass (CCD) (CCD) (CCD) 97%

U Johnson-Bessel uv 360 51 364 62%

B Johnson-Bessel blue 440 94 431 66%

V

Johnson-Bessel visual

550109 520 93%

R

Johnson-Bessel red

660142 600 83%

I Johnson-Bessel infrared

800 156 805 94%

Sloan g' SDSS green 475 150 492 96%

Sloan r' SDSS red 619 132 629 0%

Halpha neutral hydrogen 655.8/656.2 8.2 656 0%

OIII twice ionized oxygen 498.20/498.90 11.60/11.80 500 87%

Sloan z' SDSS near-IR > 900     95%

Second part of the project will be a study of their rotational periods

If the observed object have no developed comas, it should be possible to determine their rotational periods using differential photometry

Beside the study of their physical characteristics we will be able to produce new astrometrical follow –up measurements which will be reported to the Minor Planet Center

Some information for La Sagra

filter Ex time (s)

focus Description Local time (start)

Local time (end)

R 120 52.4 10 images 07 26 43 07 46 06

V 120 52.4 10 images 07 48 53 08 08 16

238P/Read

*comment: satellite flow over at 08 41 20.

filter Ex time (s)

focus Description Local time

(start)

Local time (end)

R 120 52.4 10 images 08 11 38 08 31 00

V 120 52.4 10 images 08 38 58 08 58 20

Equipment that is used

Telescope/Mode: MONET/North (robotic telescope 1.2m)

Detector: CCD camera Filters: R, V Targets: MBC with magnitude

range from mag.~15.0 till ~21.0

(La Sagra: mag. 18.4)

We don’t have final results, because the reduction is not finished yet!

Project requirementsTraining of teachers (student mentors) performed by:

Science and Education Center ,Višnjan, Croatia Petnica Science Center, Valjevo, Serbia Astronomical Observatory, Belgrade, Serbia Aristotle University of Thessaloniki, Greece

High school student projects-carried out by the schools:

Vladimir Prelog Scince School, Zagreb, Croatia Petnica Science Center, Valjevo, Serbia Gymnassium of Goumenissa, Kilkis, Greece Second Lyceum of Echedoros, Thessaloniki, Greece

Educational gains

Guided a large number of high school students through the process of scientific experiment

Educated students about recent technological developments in astronomy, using the example of robotic telescopes and sensitive CCD detectors

Exposed students to the importance of databases of astronomical images and measurements

International cooperation in science

Thank you for you attention!