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Extreme infrared variables from UKIDSS – I. A concentration in star-forming regions

Contreras Peña, C.; Lucas, P. W.; Froebrich, D.; Kumar, M. S. N.; Goldstein, J.; Drew, J. E.; Adamson, A.; Davis, C. J.; Barentsen, G.; Wright, N. J.

Authors

C. Contreras Peña

P. W. Lucas

D. Froebrich

M. S. N. Kumar

J. Goldstein

J. E. Drew

A. Adamson

C. J. Davis

G. Barentsen



Abstract

We present initial results of the first panoramic search for high-amplitude near-infrared variability in the Galactic plane. We analyse the widely separated two-epoch K-band photometry in the fifth and seventh data releases of the UKIDSS Galactic plane survey. We find 45 stars with ΔK > 1 mag, including two previously known OH/IR stars and a Nova. Even though the mid-plane is not yet included in the data set, we find the majority (66 per cent) of our sample to be within known star-forming regions (SFRs), with two large concentrations in the Serpens OB2 association (11 stars) and the Cygnus-X complex (12 stars). Sources in SFRs show spectral energy distributions that support classification as young stellar objects (YSOs). This indicates that YSOs dominate the Galactic population of high-amplitude infrared variable stars at low luminosities and therefore likely dominate the total high-amplitude population. Spectroscopic follow up of the DR5 sample shows at least four stars with clear characteristics of eruptive pre-main-sequence variables, two of which are deeply embedded. Our results support the recent concept of eruptive variability comprising a continuum of outburst events with different time-scales and luminosities, but triggered by a similar physical mechanism involving unsteady accretion. Also, we find what appears to be one of the most variable classical Be stars.

Citation

Contreras Peña, C., Lucas, P. W., Froebrich, D., Kumar, M. S. N., Goldstein, J., Drew, J. E., …Wright, N. J. (2014). Extreme infrared variables from UKIDSS – I. A concentration in star-forming regions. Monthly Notices of the Royal Astronomical Society, 439(2), 1829-1854. https://doi.org/10.1093/mnras/stu063

Journal Article Type Article
Online Publication Date Feb 7, 2014
Publication Date Apr 1, 2014
Deposit Date Jun 15, 2023
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 439
Issue 2
Pages 1829-1854
DOI https://doi.org/10.1093/mnras/stu063
Keywords Space and Planetary Science; Astronomy and Astrophysics; stars: AGB and post-AGB, stars: low-mass, stars: pre-main-sequence, stars: protostars, stars: variables: T Tauri, Herbig Ae/Be, infrared: stars