Open AccessPre‐main‐sequence stars in the Lagoon Nebula (M8) ★
Author(s) -
Arias J. I.,
Barbá R. H.,
Morrell N. I.
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.11217.x
Subject(s) - physics , astrophysics , stars , t tauri star , spectrograph , nebula , astronomy , sky , photometry (optics) , stellar classification , observatory , orion nebula , spectral line
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 λ 6708 absorption line, we are able to identify 27 classical T Tauri stars, seven weak‐lined T Tauri stars and three PMS emission objects with spectral type G, which we include in a separate stellar class denominated ‘PMS Fe/Ge class’. Using near‐infrared photometry either from the Two‐Micron All‐Sky Survey 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 3 × 10 6 yr and span over a range of masses between 0.8 and 2.5 M ⊙ . A cross‐correlation between our spectroscopic data and the X‐ray sources detected with the Chandra ACIS instrument is also presented.