# Time and phase resolved optical spectra of potentially hazardous asteroid 2014 JO25

## TL;DR

This study presents optical spectral observations of asteroid 2014 JO25 during its close approach, revealing a featureless spectrum, a phase bluing trend, and insights into its surface properties and rotation.

## Contribution

First spectroscopic analysis of asteroid 2014 JO25 during close-Earth encounter, identifying a rare phase bluing trend and estimating surface scattering parameters.

## Key findings

- Asteroid has a featureless, comet-like spectrum.
- Detected a rare phase bluing trend with increasing phase angle.
- Estimated surface properties indicating high backscattering and large single scattering albedo.

## Abstract

The asteroid 2014 JO25, considered to be "potentially hazardous" by the Minor Planet Center, was spectroscopically followed during its close-Earth encounter on 19th and 20th of April 2017. The spectra of the asteroid were taken with the low resolution spectrograph (LISA), mounted on the 1.2-m telescope at the Mount Abu Infrared Observatory, India. Coming from a region close to the Hungaria population of asteroids, this asteroid follows a comet-like orbit with a relatively high inclination and large eccentricity. Hence, we carried out optical spectroscopic observations of the asteroid to look for comet-like molecular emissions or outbursts. However, the asteroid showed a featureless spectrum, devoid of any comet-like features. The asteroid's light curve was analyzed using V band magnitudes derived from the spectra and the most likely solution for the rotation of the asteroid was obtained. The absolute magnitude $H$ and the slope parameter $G$ were determined for the asteroid in V filter band using the IAU accepted standard two parameter H-G model. A peculiar, rarely found result from these observations is its phase bluing trend. The relative B-V color index seems to decrease with increasing phase angle, which indicates a phase bluing trend. Such trends have seldom been reported in literature. However, phase reddening in asteroids is very common. The asymmetry parameter $g$ and the single scattering albedo $w$ were estimated for the asteroid by fitting the Hapke phase function to the observed data. The asteroid shows relatively large value for the single scattering albedo and a highly back scattering surface.