SCYON Abstract

Received on November 16 2006

Pre-main-sequence stars in the Lagoon Nebula (M8)

Authors	Julia I. Arias (¹), Rodolfo H. Barba (²), and Nidia I. Morrell (³)
Affiliation	(¹) Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Argentina (²) Departamento de Fisica, Universidad de La Serena, La Serena, Chile (³) Las Campanas Observatory, La Serena, Chile
Accepted by	Monthly Notices of the Royal Astronomical Society
Contact	julia@dfuls.cl
URL	http://http://xxx.lanl.gov/abs/astro-ph/0611150
Links	NGC 6530

Abstract

We report the discovery of new pre-main sequence (PMS) stars in the Lagoon Nebula (M8) at a distance of 1.25 kpc, based on intermediate resolution spectra obtained with the Boller & Chivens spectrograph at the 6.5-m Magellan I telescope (Las Campanas Observatory, Chile). According to the spectral types, the presence of emission lines and the lithium 6708A absorption line, we are able to identify 27 classical T Tauri stars, 7 weak-lined T Tauri stars and 3 PMS emission objects with spectral type G, which we include in a separated stellar class denominated "PMS Fe/Ge class". Using near-infrared photometry either from 2MASS or from our own previous work we derive effective temperatures and luminosities for these stars and locate them in the Hertzsprung-Russell diagram, in order to estimate their masses and ages. We find that almost all of our sample stars are younger than 3x10⁶ years and span over a range of masses between 0.8 and 2.5 Mo. A cross-correlation between our spectroscopic data and the X-ray sources detected with the Chandra ACIS instrument is also presented.