Incidence of high-amplitude delta Scuti type variable stars

TL;DR

This study estimates that approximately 0.3% of stars in the delta Scuti region exhibit high-amplitude delta Scuti variability, highlighting its rarity compared to low-amplitude counterparts and suggesting a brief or infrequent occurrence.

Contribution

The paper provides an order-of-magnitude estimate of the incidence of high-amplitude delta Scuti stars using a stellar distribution model and observational data from the RSV1 survey, which is a novel approach.

Findings

HADS incidence is about 0.3% among delta Scuti stars.

HADS occurrence is significantly lower than LADS.

HADS phenomenon may be short-lived or rare.

Abstract

An order-of-magnitude estimate for the incidence of high-amplitude delta Scuti-type variable stars (HADS) in the delta Scuti area of the H-R diagram is calculated. Using a model for the stellar distribution in the Milky Way, we calculate the number of stars that are expected to fall in the delta Scuti area of the H-R diagram within the magnitude range and sky coverage of the ROTSE Survey for Variables I (RSV1). The incidence of the HADS phenomenon is then obtained by comparing the number of stars calculated by the model and the actual, observed number of HADS in the RSV1. We find that ~0.3 % of the stars that lie in the delta Scuti area of the H-R diagram within the RSV1 observational limits exhibit the HADS phenomenon. This number is much lower than the incidence of the low-amplitude delta Scuti stars (LADS), ~>1/3, implying that the HADS phenomenon takes place in a very small fraction of stars and/or its duration is very short, compared to the LADS.