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Probing M subdwarf metallicity with an esdK5+esdM5.5 binary
(2015-10-15)
We present a spectral analysis of the binary G 224-58 AB that consists of the coolest M extreme subdwarf (esdM5.5) and a brighter primary (esdK5). This binary may serve as a benchmark for metallicity measurement calibrations ...
YSOVAR: Mid-infrared Variability Among YSOs in the Star Formation Region GGD 12-15
(2015-10-12)
We present an IR-monitoring survey with the $Spitzer$ Space Telescope of the star forming region GGD 12-15. Over 1000 objects were monitored including about 350 objects within the central 5 arcminutes which is found to be ...
Classical T Tauri stars with VPHAS+ -I : H α and u-band accretion rates in the Lagoon Nebula M8
(2015-10-11)
We estimate the accretion rates of 235 Classical T Tauri star (CTTS) candidates in the Lagoon Nebula using $ugri$H$\alpha$ photometry from the VPHAS+ survey. Our sample consists of stars displaying H$\alpha$-excess, the ...
Starspot distributions on fully convective M dwarfs : implications for radial velocity planet searches
(2015-10-07)
Since M4.5 - M9 dwarfs exhibit equatorial rotation velocities of order 10 km/s on average, radial velocity surveys targeting this stellar population will likely need to find methods to effectively remove starspot jitter. ...
YSOVAR: mid-infrared variability of young stellar objects and their disks in the cluster IRAS 20050+2720
(2015-09-22)
We present a time-variability study of young stellar objects in the cluster IRAS 20050+2720, performed at 3.6 and 4.5 micron with the Spitzer Space Telescope; this study is part of the Young Stellar Object VARiability ...
Smoke in the Pipe Nebula: dust emission and grain growth in the starless core FeSt 1-457
(2015-08-13)
(abridged) Methods: We derive maps of submillimeter dust optical depth and effective dust temperature from Herschel data that were calibrated against Planck. After calibration, we then fit a modified blackbody to the ...
Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs I : Characterizing Benchmarks, Gl570D and HD3651B
(2015-07-10)
Interpreting the spectra of brown dwarfs is key to determining the fundamental physical and chemical processes occurring in their atmospheres. Powerful Bayesian atmospheric retrieval tools have recently been applied to ...
49 new T dwarfs identified using methane imaging
(2015-07-01)
We present the discovery of 49 new photometrically classified T dwarfs from the combination of large infrared and optical surveys combined with follow-up TNG photometry. We used multi-band infrared and optical photometry ...
A large spectroscopic sample of L and T dwarfs from UKIDSS LAS : peculiar objects, binaries, and space density
(2015-06-01)
We present the spectroscopic analysis of a large sample of late-M, L, and T dwarfs from UKIDSS. Using the YJHK photometry from ULAS and the red-optical photometry from SDSS we selected a sample of 262 brown dwarf candidates ...
Subclasses of Type Ia Supernovae as the origin of [α/Fe] ratios in dwarf spheroidal galaxies
(2015-04-23)
Recent extensive observations of Type Ia Supernovae (SNe Ia) have revealed the existence of a diversity of SNe Ia, including SNe Iax. We introduce two possible channels in the single degenerate scenario: 1) double detonations ...