2008/03/31 by Dagny L. Looper, D. L. Looper, C. R. Gelino +5 · 1 citation
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/590382
published as 2008ApJ...685.1183L · 13 pages, 8 figures; accepted to ApJ - added two extra paragraphs explaining our methodology in more detail, updated reference list
openalex publication_date 2008/09/26 · arxiv created 2008/10/08 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present Keck laser guide star observations of two T2.5 dwarfs—2MASS J11061197+2754225 and 2MASS J14044941–3159329—using NIRC2 on Keck II and find 2MASS J14044941–3159329 to be a 0.13 '' binary. This system has a secondary that is 0.45 mag brighter than the primary in J band, but 0.49 mag fainter in H band and 1.13 mag fainter in K s band. We use this relative photometry along with near-infrared synthetic modeling performed on the integrated light spectrum to derive component types of T 1 ± 1 for the primary and T 5 ± 1 for the secondary. Optical spectroscopy of this system obtained with Magellan/LDSS-3 is also presented. This is the fourth L/T transition binary to show a flux reversal in the 1-1.2 μm regime, and this one has the largest flux reversal. Unless the secondary is itself an unresolved binary, the J -band magnitude difference between the secondary and primary shows that the J -band "bump" is indeed a real feature and not an artifact caused by unresolved binarity.