scholarly journals Middle-Infrared Observations of DENIS J0255-4700

2003 ◽  
Vol 211 ◽  
pp. 421-422
Author(s):  
Michelle Creech-Eakman ◽  
Eugene Serabyn ◽  
Glenn S. Orton ◽  
Thomas L. Hayward
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Infrared Photometry ◽  
Atmospheric Models ◽  
Brown Dwarf ◽  
Infrared Observations ◽  
Upper Limits ◽  
Model Independent ◽  
Data Yield ◽  
Middle Infrared

The first infrared photometry of an L-type brown dwarf, DENIS J0255-4700, includes N-band and narrow-band 8.8-μm detections, with upper limits in narrow-band 10.3 and 11.7 μm. Model-independent blackbody fits of existing data yield Teff = 1250 – 1750 K, with models favoring the lower end of that range. Dusty atmospheric models by Allard, Burrows and Marley which match the near-infrared photometry are not completely consistent with our mid-infrared photometry.

scholarly journals Dynamical masses for the nearest brown dwarf binary: ε Indi Ba,b

2009 ◽  
Vol 5 (H15) ◽  
pp. 761-761
Author(s):  
C. V. Cardoso ◽  
M. J. McCaughrean ◽  
R. R. King ◽  
L. M. Close ◽  
R.-D. Scholz ◽  
...  
Keyword(s):  
Main Sequence ◽  
Brown Dwarfs ◽  
Evolutionary Models ◽  
Atmospheric Models ◽  
Brown Dwarf ◽  
Near Ir ◽  
The Earth ◽  
Benchmark System ◽  
Model Independent ◽  
Dynamical Masses

Binary brown dwarfs are important because their dynamical masses can be determined in a model-independent way. If a main sequence star is also involved, the age and metallicity for the system can be determined, making it possible to break the sub-stellar mass-age degeneracy. The most suitable benchmark system for intermediate age T dwarfs is ε Indi Ba,b, two T dwarfs (spectral types T1 and T6; McCaughrean et al. (2004)) orbiting a K4.5V star, ε Indi A, at a projected separation of 1460AU. At a distance of 3.6224pc (HIPPARCOS distance to ε Indi A; van Leeuwen (2007)), these are the closest brown dwarfs to the Earth, and thus both components are bright and the system is well-resolved. The system has been monitored astrometrically with NACO and FORS2 on the VLT since June 2004 and August 2005, respectively, in order to determine the system and individual masses independent of evolutionary models. We have obtained a preliminary system mass of 121±1MJup. We have also analysed optical/near-IR spectra (0.6-5.0μm at a resolution up to R~5000; King et al. (2009)) allowing us to determine bolometric luminosities, compare and calibrate evolutionary and atmospheric models of T dwarfs at an age of 4-8Gyr.

scholarly journals Abundance Effects in the Classification of K Stars

1976 ◽  
Vol 72 ◽  
pp. 87-90
Author(s):  
P. M. Williams
Keyword(s):  
Spectral Type ◽  
Near Infrared ◽  
Narrow Band ◽  
Infrared Photometry ◽  
Metal Abundance ◽  
Metal Abundances ◽  
Effective Temperatures

The influence of metal abundance and gravity on the relation between spectral type and effective temperatures of late G and K type stars is investigated and calibrated using metal abundances from narrow-band photometry, near infrared photometry and independent luminosity estimates.

scholarly journals Discovery of a Tight Brown Dwarf Companion to the Low Mass Star LHS 2397a

2003 ◽  
Vol 211 ◽  
pp. 261-264 ◽  
Author(s):  
Melanie Freed ◽  
Laird M. Close ◽  
Nick Siegler
Keyword(s):  
Adaptive Optics ◽  
Spectral Type ◽  
Proper Motion ◽  
Near Infrared ◽  
Mass Star ◽  
Infrared Photometry ◽  
Brown Dwarf ◽  
Dynamical Mass ◽  
Low Mass ◽  
Adaptive Optics System

Using the adaptive optics system, Hōkūpa'a, at Gemini-North, we have directly imaged a companion around the UKIRT faint standard M8 star, LHS 2397a (FS 129) at a separation of 2.96 AU. Near-Infrared photometry obtained on the companion has shown it to be an L7.5 brown dwarf and confirmed the spectral type of the primary to be an M8. We also derive a substellar mass of the companion of 0.068M⊙, although masses in the range (0.061 – 0.069) are possible, and the primary mass as 0.090M⊙ (0.089 – 0.094). Reanalysis of archival imaging from HST has confirmed the secondary as a common proper motion object. This binary represents the first clear example of a brown dwarf companion within 4 AU of a low mass star, and should be the first L7.5 to have a dynamical mass. As part of a larger survey of M8-M9 stars, this object may indicate that there is no “brown dwarf desert” around low mass primaries.

scholarly journals Ground-Based Near-Infrared Observations of Global Solar Oscillations

1994 ◽  
Vol 154 ◽  
pp. 277-282
Author(s):  
L. V. Didkovsky ◽  
V. A. Kotov
Keyword(s):  
Solar Irradiance ◽  
Near Infrared ◽  
Solar Oscillations ◽  
Infrared Observations ◽  
Space Experiments ◽  
Upper Limits ◽  
Solar Brightness ◽  
The Mean ◽  
Photodiode Arrays ◽  
Spectral Ranges

Near-infrared (0.7-1.0 μm) observations of solar brightness oscillations were performed in 1983-1991 at the Crimean Solar Tower with the use of two (16 × 16 and 32 × 32) photodiode arrays. In 1991 new observations of p-modes were made simultaneously in two spectral ranges, near 0.7 and 1.0 μm. The data is analysed to check for the presence of solar variation with the 160-min period. It is found that the mean relative amplitude for the 160-min solar irradiance variation at 0.73 - 1.65 μm wavelengths, ~ 2 × 10–6, is much lower than the upper limits set by the ACRIM and IPHIR space experiments.

Temperatures of Peculiar G-Type Stars from Narrow-Band Near-Infrared Photometry

2000 ◽  
Vol 177 ◽  
pp. 588-588
Author(s):  
Robert F. Wing ◽  
Robert F. Garrison ◽  
Tuba Koktay
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Infrared Photometry

scholarly journals THE COLLAPSE OF THE WIEN TAIL IN THE COLDEST BROWN DWARF? HUBBLE SPACE TELESCOPE NEAR-INFRARED PHOTOMETRY OF WISE J085510.83–071442.5

2016 ◽  
Vol 823 (2) ◽  
pp. L35 ◽  
Author(s):  
Adam C. Schneider ◽  
Michael C. Cushing ◽  
J. Davy Kirkpatrick ◽  
Christopher R. Gelino
Keyword(s):  
Near Infrared ◽  
Hubble Space Telescope ◽  
Infrared Photometry ◽  
Brown Dwarf ◽  
Space Telescope

scholarly journals Search for π0 decays to invisible particles

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
E. Cortina Gil ◽  
◽  
A. Kleimenova ◽  
E. Minucci ◽  
S. Padolski ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Branching Ratio ◽  
Standard Model Higgs Boson ◽  
Scalar Mixing ◽  
Upper Limit ◽  
Upper Limits ◽  
The Standard Model ◽  
Model Independent

Abstract The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.

scholarly journals Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

1997 ◽  
Vol 163 ◽  
pp. 725-726
Author(s):  
K.-W. Hodapp ◽  
E. F. Ladd
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Point Sources ◽  
Spectral Energy ◽  
Infrared Observations ◽  
Circumstellar Material ◽  
Dense Cores ◽  
Wavelength Radiation ◽  
Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

Near infrared photometry of stellar maser sources

1986 ◽  
Vol 10 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Ke-ping Zhou ◽  
Yun-xiang Hao ◽  
Pei-sheng Chen ◽  
Yun Zhang ◽  
Heng Gao
Keyword(s):  
Near Infrared ◽  
Infrared Photometry ◽  
Maser Sources
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