A New Titanium Oxide Index in Visual Band

TL;DR

This paper introduces a new visual-band TiO absorption index for measuring stellar temperatures in late K to M stars, enhancing observational capabilities with small telescopes.

Contribution

The paper presents a novel TiO index based on spectral data, validated with observations, extending temperature measurement methods into the visual spectrum.

Findings

The new index correlates with stellar temperature from 2800K to 4000K.

It behaves similarly to the traditional Wing TiO index.

The index is suitable for small telescope observations.

Abstract

We introduce a new color index consisting of two spectral band width to measure TiO absorption band strength centered at 567 nm. Based on the most up-to-date line list for TiO we regenerate a grid of synthesized spectra and investigate the temperature sensitivity of the index. The new index behave similar to older Wing TiO-index where itdecreas emonotonically from coolest atmosphere with Teff =2800 up to Teff =4000 where the TiO molecules disassociate. To further examine the feasibility of the new index we reproduce the calibration using a list of observed high resolution spectra and found similar results. This index extend TiO absorption band capability to measure effective temperature of late K to M stars to visual spectrum where it is more accessible to small telescopes for long term dedicated observation.