Projects per year
Abstract
We present simultaneous photometric and spectroscopic observations of
seven young and highly variable M dwarfs in star-forming
regions in Orion, conducted in four observing
nights with FOcal Reducer and low dispersion Spectrograph2 at European
Southern
Observatory/VLT. All seven targets show significant
photometric variability in the I band, with amplitudes between
0.1–0.8 mag, The spectra, however, remain remarkably constant, with
spectral type changes less
than 0.5 subtypes. Thus, the brightness changes are
not caused by veiling that ‘fills in’ absorption features. Three
objects
in the σ Ori cluster (age ∼3 Myr) exhibit strong Hα
emission and Hα variability, in addition to the continuum variations.
Their behaviour is mostly consistent with the
presence of spots with temperature of ∼300 K above the photosphere and
filling
factors between 0.2–0.4, in contrast to typical
hotspots observed in more massive stars. The remaining targets near
ϵ Ori,
likely to be older, show eclipse-like light curves,
no significant Hα activity and are better represented by variable
extinction
due to circumstellar material. Interestingly, two
of them show no evidence of infrared excess emission. Our study shows
that
high-amplitude variability in young very low mass
stars can be caused by different phenomena than in more massive T Tauri
stars and can persist when the disc has disappeared
and accretion has ceased.
Original language | English |
---|---|
Pages (from-to) | 3118-3133 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 458 |
Issue number | 3 |
Early online date | 7 Mar 2016 |
DOIs | |
Publication status | Published - 21 May 2016 |
Keywords
- Brown dwarfs
- Stars: low-mass
- Stars: pre-main-sequence
- Stars: variables: T Tauri
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Dive into the research topics of 'Variability in young very low mass stars: two surprises from spectrophotometric monitoring'. Together they form a unique fingerprint.Projects
- 4 Finished
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Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018
Jardine, M. M. (PI), Cameron, A. C. (CoI), Cyganowski, C. J. (CoI), Horne, K. D. (CoI) & Wood, K. (CoI)
Science & Technology Facilities Council
1/04/15 → 31/03/18
Project: Standard
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PATT linked Travel and Subsistence: St Andrrews Astronomy PATT linked Travel and subsistence
Cameron, A. C. (PI), Driver, S. P. (CoI), Greaves, J. S. (CoI) & Horne, K. D. (CoI)
Science & Technology Facilities Council
1/10/10 → 30/09/13
Project: Standard
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PATT Linked Travel ST/G001006/1: Patt Linked Travel & Subsistence
Cameron, A. C. (PI), Driver, S. P. (CoI), Greaves, J. S. (CoI) & Horne, K. D. (CoI)
Science & Technology Facilities Council
1/10/08 → 30/09/10
Project: Standard