Brown dwarf

A brown dwarf is a type of substellar object occupying the mass range between the heaviest gas giant planets and the lightest stars, having a mass between 13 and 75–80 times that of Jupiter, or 2.5×1028 kg to about 1.5×1029 kg. Below this range are the sub-brown dwarfs, above it are the lightest red dwarfs. Brown dwarfs may be convective, with no layers or chemical differentiation by depth. Unlike the stars in the main sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen to helium in their cores, they are, thought to fuse deuterium and to fuse lithium if their mass is above a threshold of 13 MJ and 65 MJ, respectively. It is debated whether brown dwarfs would be better defined by their formation processes rather than by their nuclear fusion reactions. Stars are categorized by spectral class, with brown dwarfs designated as types M, L, T, Y. Despite their name, brown dwarfs are of different colors. Many brown dwarfs would appear magenta to the human eye, or orange/red.

Brown dwarfs are not luminous at visible wavelengths. There are planets known to orbit brown dwarfs: 2M1207b, MOA-2007-BLG-192Lb, 2MASS J044144b. At a distance of about 6.5 light years, the nearest known brown dwarf is Luhman 16, a binary system of brown dwarfs discovered in 2013. HR 2562 b is listed as the most-massive known exoplanet in NASA's exoplanet archive, despite having a mass more than twice the 13-Jupiter-mass cutoff between planets and brown dwarfs; the objects now called "brown dwarfs" were theorized to exist in the 1960s by Shiv S. Kumar and were called black dwarfs, a classification for dark substellar objects floating in space that were not massive enough to sustain hydrogen fusion. However: the term black dwarf was in use to refer to a cold white dwarf; because of this, alternative names for these objects were proposed, including substar. In 1975, Jill Tarter suggested the term "brown dwarf"; the term "black dwarf" still refers to a white dwarf that has cooled to the point that it no longer emits significant amounts of light.

However, the time required for the lowest-mass white dwarf to cool to this temperature is calculated to be longer than the current age of the universe. Early theories concerning the nature of the lowest-mass stars and the hydrogen-burning limit suggested that a population I object with a mass less than 0.07 solar masses or a population II object less than 0.09 M☉ would never go through normal stellar evolution and would become a degenerate star. The first self-consistent calculation of the hydrogen-burning minimum mass confirmed a value between 0.08 and 0.07 solar masses for population I objects. The discovery of deuterium burning down to 0.012 solar masses and the impact of dust formation in the cool outer atmospheres of brown dwarfs in the late 1980s brought these theories into question. However, such objects were hard to find because they emit no visible light, their strongest emissions are in the infrared spectrum, ground-based IR detectors were too imprecise at that time to identify any brown dwarfs.

Since numerous searches by various methods have sought these objects. These methods included multi-color imaging surveys around field stars, imaging surveys for faint companions of main-sequence dwarfs and white dwarfs, surveys of young star clusters, radial velocity monitoring for close companions. For many years, efforts to discover brown dwarfs were fruitless. In 1988, however, a faint companion to a star known as GD 165 was found in an infrared search of white dwarfs; the spectrum of the companion GD 165B was red and enigmatic, showing none of the features expected of a low-mass red dwarf. It became clear that GD 165B would need to be classified as a much cooler object than the latest M dwarfs known. GD 165B remained unique for a decade until the advent of the Two Micron All-Sky Survey which discovered many objects with similar colors and spectral features. Today, GD 165B is recognized as the prototype of a class of objects now called "L dwarfs". Although the discovery of the coolest dwarf was significant at the time, it was debated whether GD 165B would be classified as a brown dwarf or a very-low-mass star, because observationally it is difficult to distinguish between the two.

Soon after the discovery of GD 165B, other brown-dwarf candidates were reported. Most failed to live up to their candidacy, because the absence of lithium showed them to be stellar objects. True stars burn their lithium within a little over 100 Myr. Hence, the detection of lithium in the atmosphere of an object older than 100 Myr ensures that it is a brown dwarf; the first Brown Dwarf was discovered in 1994 by Caltech astronomers Kulkarni, Tadashi Nakajima, Keith Matthews, Rebecca Oppenheimer, Johns Hopkins scientists Sam Durrance and David Golimowski. It was confirmed in 1995 as a substellar companion to Gliese 229. Gliese 229b is one of the first two instances of clear evidence for a brown dwarf, along with Teide 1. Confirmed in 1995, both were identified by the presence of the 670.8 nm lithium line. The latter was found to luminosity well below the stellar range, its near-infrared spectrum exhibited a methane absorption band at 2 micrometres, a feature that had only been observed in the

Kashmere Stage Band

Kashmere Stage Band was an elite performing unit of the student band at Kashmere High School from the late 1960s until 1978. Kashmere High School is located in a predominantly black neighborhood known as Kashmere Gardens in Houston, Texas. Music teacher Conrad O. Johnson attended an Otis Redding concert in 1967 and was inspired to translate the style of the concert into a program he could sustain at the high school in order to create opportunities for his student musicians, thus the Kashmere Stage Band was born. During its time, KSB won national championships in high school band competitions and gained a reputation as being unbeatable. Johnson served as band director and principal composer for the band. KSB recorded eight albums during its life; the teenagers in the Kashmere Stage Band produced a sound equal to that of the contemporary funk bands the JBs and the Bar-Kays. Although lost for decades, since 2003 the KSB recordings have been released, some for the first time, on both vinyl record and CD and have become prized by hip-hop artists and DJs for their inimitable sound.

A notable sampling occurs on the Handsome Boy Modeling School album So... How's Your Girl?. Stones Throw Records imprint label Now-Again Records released a compilation of KSB material in 2006, Texas Thunder Soul 1968–1974. In February 2008, thirty original members of the Kashmere Stage Band, all in their mid-50s, reunited for the first time in over three decades to pay tribute to their legendary leader, Conrad "Prof" Johnson, 92 at the time; the story of Prof, the exceptional music program he built, the historic reunion of his former students was captured in a feature-length documentary film, Thunder Soul, narrated by Jamie Foxx, released in theaters on September 23, 2011. Our Thing Bumper to Bumper Soul Thunder Soul Zero Point Out of Gas "But Still Burning" Kashmere "73" Live In Concert Expo.'75 - Concert Tour Japan / Okinawa Texas Thunder Soul 1968–1974 Plays Originals Kashmere Stage Band's song "Kashmere" was featured on the Baby Driver film's soundtrack, released under Columbia Records on June 23, 2017.

Official website David Brown of Austin's KUT interviews Conrad Johnson Conrad O. Johnson Hall of Fame profile Documentary on Kashmere Stage Band Midheaven Mailorder re-issues and remixes re-issue of "Zero Point" The Conrad O. Johnson Music & Fine Arts Foundation NPR's All Things Considered story about the band Gray and John Nova Lomax; the Return of the Kashmere Stage band." Houston Press. February 5, 2008


Torrespaña is a 231 m steel-and-concrete television tower located in Madrid, Spain. National terrestrial television channels RTVE, Telecinco and Antena 3, as well as the autonomous channel Telemadrid, along with a few radio stations, broadcast from the tower; the tower was built in 1982. The building was administered by RTVE until 1989, when control over radio and television emissions in Spanish territory was given to Retevisión, it is known in Madrid as the "Pirulí", given the similarity between the tower and a particular type of lollipop of conical shape popular in Spain in the eighties. Located in a depression, next to the M30 highway, the tower is not open to the public. Media related to Torrespaña at Wikimedia Commons