Robert King
Home People Home Research

Epsilon Indi Ba, Bb: the closest known binary brown dwarf system.

I have recently completed work on the nearby binary brown dwarfs Indi Ba and Bb. I reduced VLT photometry and spectroscopy from the optical through to the thermal-IR (0.6-5.1 micron) which allowed a detailed comparison with atmospheric and evolutionary models of sub-stellar objects at intermediate age. The comparison with the Lyon atmospheric models has identified areas of the models where improvements can be made and also highlighted the problem of deriving inaccurate physical properties even for seemingly well-constrained systems. I am also involved in the astrometric monitoring of this binary which has allowed a preliminary determination of the total system mass and on-going absolute astrometry will determine the mass ratio and hence the individual masses. Together with the luminosity determinations, these observations will provide an extremely well characterised system which will tightly constrain future evolutionary models.
Full spectra of Epsilon Indi Ba and Bb available here.
If you make use of these data please acknowledge our paper, King et al. 2010.

Atmopsheres of very low-mass companions to young stars

I am also searching for and characterising substellar companions to young stars involving the characterisation of ~12 young L dwarfs by comparison of their near-IR spectra to synthetic stellar spectra. The existing measurments of these objects are being extended into the thermal-IR regime which will allow us to more accurately determine their luminosities and effective temperatures as well as allowing a probe of the L to T transition in young objects.

Near-IR and X-ray study of High-Mass Star Formation Regions (HMSFRs)

Working with Tim Naylor, Mark McCaughrean and collaborators from Penn. State, I am also using optical and near-IR observations of young, high-mass star forming regions in combination with X-ray observations to select bona-fide cluster members of several massive star clusters. We hope to combine these multi-wavelength data for 10-20 clusters in massive star-forming environments, to consistently compare properties such as evidence of mass segregation, binarity and the form of the IMF, free of the problems associated with a myriad of selection techniques.
OH linelists 1.154-4.837 microns.
This file contains the theoretical wavelength and measured intensity of the OH Meinel bands in the region 1.154 - 4.837 microns. These are useful for wavelength calibration of NIR spectra as they are observed at the same time as your object(s) of interest and give relatively good wavelength coverage. These data are taken from Abrams et al. 1994, ApJS, 93, 351, dug out by James Graham.