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New paper published: Lightcurve Analysis for Three Main-Belt Asteroids

Following a peer review process, a scientific paper by Stephen M. Brincat – Flarestar Observatory entitled ‘Lightcurve Analysis for Three Main-Belt Asteroids’ was accepted and published on the front page of Volume 44-1 of the *Minor Planet Bulletin* (MPB). The MPB is a quarterly peer reviewed open-access scientific journal that focuses primarily on minor planets (asteroids). Articles in this journal routinely portray minor planets from observational, theoretical to historical perspectives. The MPB has been published by the Minor Planets Section of the Association of Lunar and Planetary Observers (ALPO) since 1973 and the editor-in-chief is Professor Richard P. Binzel (Massachusetts Institute of Technology). All MPB articles are available through the SAO/NASA Astrophysics Data System Abstract Service.

The above mentioned paper had the objective to acquire photometric observations of three main-belt asteroids that had no known synodic rotation periods (length of day) at the time of observation. The asteroids under study were 1154 Astronomia (1927 CB), 3680 Sasha (1987 MY) and (6138) 1991 JH1. Differential photometry was employed to determine synodic rotation period. The acquisition of photometric data allows the transformation of data points into lightcurves (graphs that illustrate brightness against time) that enables to derive asteroid rotation periods.

All observations in the paper were acquired at Flarestar Observatory (IAU/MPC Code: 171) that employed a 0.25-m f/6.3 Schmidt-Cassegrain telescope. A G2-1600 Moravian CCD set at a sensor temperature of -15° C was employed as the main camera at the telescope.

1154 Astronomia (1927 CB) is an outer main belt asteroid orbiting the Sun every 6 years. It is approximately 61 kilometres in diameter. 1154 Astronomia was observed on 8 nights from 2016 May 5 to June 14. 347 photometric observations were acquired to find the synodic period of this asteroid that was derived as 18.1154 ± 0.0139 h with an amplitude (brightness) range of 0.39 ± 0.05 magnitudes.

During the month of March 2016, 3680 Sasha (1987 MY) was observed on four nights. A lightcurve made up of 329 data points showed that the asteroid’s synodic period is of 5.8145 ± 0.005 h with amplitude of 0.30 ± 0.05 mag. BTW, this asteroid is named after the daughter of the famous astronomer Carl Sagan. She is portrayed on the following YouTube link – https://www.youtube.com/watch?v=_0DwDu9N_-0

Discovered in 1991, 6138 (1991 JH1) is an asteroid that is officially numbered as 6138 and is still waiting to be named. . This main-belt minor planet was observed over a period of 3 nights ranging from 2016 March 27 to April 10th. 218 data points were acquired that formed the basis of the lightcurve. Lightcurve analysis derived a synodic period of 5.4578 ± 0.006 h with amplitude of 0.30 ± 0.09 mag.

All analysis for the above mentioned asteroids, were derived through Fourier analysis to find the correct period.

This paper is expected to be available in the coming days through the NASA Abstract Service. Full paper is already available from the MPB website: www.minorplanet.info/MPB/MPB_44-1.pdf

Below are the final lightcurves obtained for these three asteroids.

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