The Keele–Exeter young cluster survey – I. Low-mass pre-main-sequence stars in NGC 2169

Jeffries, R.D.; Oliveira, J.M.; Naylor, Tim; Mayne, N.J.; Littlefair, S.P.

Abstract

We have used R_C I_C CCD photometry from the Isaac Newton telescope and intermediate resolution spectroscopy from the Gemini North telescope to identify and characterise low-mass (0.15<M/M_sun<1.3) pre-main sequence stars in the young open cluster NGC 2169. Isochrone fitting to the high- and low-mass populations yields an intrinsic distance modulus of 10.13{+0.06}{-0.09} mag and a model-dependent age of 9+/-2 Myr. Compared with the nearby, kinematically defined groups of a similar age, NGC 2169 has a large low-mass population which potentially offers a more precise statistical investigation of several aspects of star formation and early stellar evolution. By modelling the distribution of low-mass stars in the I_C versus R_C-I_C diagram we find that any age spread among cluster members has a Gaussian full width at half maximum <=2.5 Myr. A young age and small age spread (<10 Myr) are supported by the lack of significant lithium depletion in the vast majority of cluster members. There is no clear evidence for accretion or warm circumstellar dust in the low-mass members of NGC 2169, bolstering the idea that strong accretion has ceased and inner discs have dispersed in almost all low-mass stars by ages of 10 Myr.

Citation

Jeffries, R., Oliveira, J., Naylor, T., Mayne, N., & Littlefair, S. (2007). The Keele–Exeter young cluster survey – I. Low-mass pre-main-sequence stars in NGC 2169. Monthly Notices of the Royal Astronomical Society, 376(2), 580 -598. https://doi.org/10.1111/j.1365-2966.2007.11327.x

• Journal Article Type: Article
• Acceptance Date: Nov 21, 2006
• Online Publication Date: Apr 13, 2007
• Publication Date: 2007-04
• Publicly Available Date: May 26, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 376
• Issue: 2
• Pages: 580 -598
• DOI: https://doi.org/10.1111/j.1365-2966.2007.11327.x
• Keywords: stars, pre-main sequence, abundances, late-type, open clusters and associations, individual, NGC 2169
• Publisher URL: http://dx.doi.org/10.1111/j.1365-2966.2007.11327.x