A peculiar young eruptive star in the dark cloud Lynds 1340

TL;DR

This study monitors a young, eruptive star in Lynds 1340 over 12 years, revealing large brightness variations driven by changing accretion rates and inner disk structures, offering insights into early stellar evolution.

Contribution

It provides a detailed long-term observational analysis of an eruptive young star, highlighting the link between brightness variations and accretion dynamics, which was previously less understood.

Findings

Star exhibits 5-6 magnitude brightness variations over years.

Variations linked to changes in accretion rate and inner disk structure.

Star's properties suggest similarity to V1647 Ori.

Abstract

We conducted a long-term optical photometric and spectroscopic monitoring of the strongly variable, accreting young sun-like star [KOS94] HA11, associated with the dark cloud Lynds 1340, that exhibited large amplitude (5-6 magnitudes in the I_C band) brightness variations on 2-3 years timescales, flat spectral energy distribution (SED), and extremely strong (300 < EW/Angstrom < 900) H alpha emission. In this Letter we describe the basic properties of the star, derived from our observations between 1999 and 2011, and put into context the observed phenomena. The observed variations in the emission spectra, near-infrared colors, and SED suggest that [KOS94] HA11 (spectral type: K7--M0) is an eruptive young star, possibly similar in nature to V1647 Ori: its large-scale photometric variations are governed by variable accretion rate, associated with variations in the inner disk structure. The star recently has undergone strong and rapid brightness variations, thus its further observations may offer a rare opportunity for studying structural and chemical rearrangements of the inner disk, induced by variable central luminosity.