Absolute colours and phase coefficients of trans-Neptunian objects: HV − HR and relative phase coefficients

Abstract

The trans-Neptunian objects (TNOs) are small Solar System bodies at large\ndistances from the Sun. As such, their physical properties are difficult to\nmeasure. Accurate determination of their physical parameters is essential to\nmodel and theorize the actual composition and distribution of the population,\nand to improve our understanding of the formation and evolution of the Solar\nSystem. The objective of this work is to construct phase curves in two filters,\n$V$ and $R$, of a large TNO sample obtaining absolute magnitudes ($H$) and\nphase coefficients ($\\beta$), and study possible relations between them and\nother physical parameters (orbital elements, sizes, and albedos). We used our\nown data, together with data from the literature, to create the phase curves\nassuming an overall linear trend. We obtained new magnitudes for 35 TNOs, 27 in\nthe V filter and 35 in the R filter. These magnitudes, together with data from\nthe literature, allowed us to obtain absolutes magnitudes, 114 in the V filter\nand 113 in the R filter, of which 106 have both. From the search for\ncorrelations we found a strong anticorrelation between $H_V-H_R$ and $\\Delta\n\\beta=\\beta_V-\\beta_R$, which is probably more related to surface structure\nthan to composition or size of the objects.\n