Astrometric and photometric observations of six brightest trans-Neptunian objects at the Kyiv comet station

TL;DR

This study reports astrometric and photometric observations of six bright trans-Neptunian objects using a 0.7-m telescope, providing data on their positions, magnitudes, and colors to understand observational limitations.

Contribution

It presents new observational data of six TNOs using a small telescope, analyzing the accuracy and limitations of such observations for faint objects.

Findings

Measured astrometric positions and magnitudes in multiple bands.

Calculated absolute magnitudes and color indices.

Analyzed observational limitations of a 0.7-m telescope for faint TNOs.

Abstract

In this work, we focused on observations of six trans-Neptunian objects (TNOs) whose apparent magnitudes are brighter than 20 mag. We present the results of astrometric and photometric observations of (134340) Pluto, (136108) Haumea, (136472) Makemake, (136199) Eris, (90482) Orcus and (20000) Varuna obtained at the Kyiv comet station (Code MPC 585) in 2017-2019. For observations, we used the 0.7-m reflector AZT-8 with the FLI PL4710 CCD camera and filters of the Johnson-Cousins photometric system. From our images, we measured the objects astrometric positions, calculated apparent magnitudes in the BVRI (mostly R) bands using the aperture photometry method, and found the absolute magnitudes together with the colour indices in several bands. Analysing our results, we investigate the limitation on the astrometry and photometry of faint objects with the 0.7-m telescope.