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Wilmington, North Carolina once had a thriving Black middle class and an elected interracial government. In 1898 white supremacists used violence to overthrow that government, kill Black residents and drive many others from the city.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Virgo[1] |
| Right ascension | 15h 08m 51.7367s[2] |
| Declination | +02° 20′ 35.962″[2] |
| Apparent magnitude (V) | 11.3[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F8/9[3] |
| Astrometry | |
| Radial velocity (Rv) | −17.46±0.58[2] km/s |
| Proper motion (μ) | RA: −16.741 mas/yr[2] Dec.: −8.556 mas/yr[2] |
| Parallax (π) | 3.0330±0.0208 mas[2] |
| Distance | 1,075 ± 7 ly (330 ± 2 pc) |
| Details | |
| Mass | 1.184±0.027[3] M☉ |
| Radius | 1.331±0.032[3] R☉ |
| Surface gravity (log g) | 4.26 ± 0.02[4] cgs |
| Temperature | 6107 ± 77[4] K |
| Metallicity [Fe/H] | –0.02 ± 0.10[4] dex |
| Rotational velocity (v sin i) | 7.32 ± 0.88[5] km/s |
| Age | 3.8+1.3 −1.2[3] Gyr |
| Other designations | |
| TOI-5685, TIC 460396820, WASP-24, TYC 339-329-1, 2MASS J15085174+0220358, USNO-B1.0 0923-0348089[6] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
WASP-24 is an F-type star with the hot Jupiter planet WASP-24b in orbit, about 1,075 light-years away in the constellation Virgo. WASP-24 is slightly larger and more massive than the Sun, it also has a similar metallicity and is hotter than the Sun. WASP-24 was first observed by the SuperWASP planet-searching organization, which flagged it as a potential host to a planet before following up with radial velocity and spectral measurements. Analysis of these confirmed the planetary nature of WASP-24b, which was later released to the public on the SuperWASP website.
An eclipsing binary pair of companion stars were identified by a 2019 study using Gaia DR2 data. They are separated by 21.8 arcseconds from the primary star, corresponding to a distance of 7097 AU.[7]
Between March 2008 and April 2009, the northern and southern portions of the SuperWASP Consortium observed the night sky in WASP-24's vicinity. The star, in particular, was flagged as a host to a planetary candidate. After accumulating over 9,750 datapoints for a light curve on WASP-24, all information on the star that had been previously catalogued was collected alongside the new data, and the star was set aside for manual follow-up observations.[3]
The 2.56m Nordic Optical Telescope (NOT) at the Canary Islands' Roque de los Muchachos Observatory was used to collected radial velocity measurements. The Fibre-Fed Echelle Spectrograph, or FIES, was the instrument that collected these observations between December 2008 and April 2009; also used was the CORALIE spectrograph on the Leonhard Euler Telescope at Chile's La Silla Observatory, which collected additional radial velocity and spectral measurements. Analysis of WASP-24's spectrum ruled out the possibility that WASP-24 is a rapidly rotating star, which could make confirmation of a planet difficult, or that it is a spectroscopic binary star system. Use of a span bisector analysis revealed that the star is not very active.[3] WASP-24 was then observed using Hawaii's Faulkes Telescope North and Australia's Faulkes Telescope South, searching for a period at which the discovered planet WASP-24b might transit, or cross in front of, its star, over various days in 2009 and 2010.[3]
Using information collected by NOT, WASP-24's temperature, metallicity, and other characteristics were derived. Detected levels of lithium and the star's surface gravity suggests that the star does not follow the main sequence.[3] These stellar characteristics were later used to derive its planet's characteristics.[3]
WASP-24 and, specifically, the discovery of orbiting hot Jupiter WASP-24b were first reported on SuperWASP's website in April 2010,[8] followed by its formal publication in September 2010.[3]
WASP-24 is an F-type star that lies 330 parsecs, or 1,075 light years, away.[2] With an apparent magnitude of 11.3, the star is invisible to the naked eye from the Earth's perspective. WASP-24 is 1.129 solar masses and 1.147 solar radii, making it just slightly larger and more massive than the Sun. It is also hotter, with an effective temperature of 6100 K. The star has a metallicity similar to that of the sun, which means that it has the same amount of metals (elements heavier than He) as found in the Sun.[4] The best fit for WASP-24's age is 3.8 billion years, although this is not well-constrained, and its actual age may lie anywhere between 2.6 and 5.1 billion years.[3]
The star's surface gravity, logg = 4.15, and its low levels of lithium helped derive the star's age, and revealed that it most likely evolved away from the zero age main sequence.[3]
WASP-24b is a hot Jupiter that is 1.091 Jupiter masses and 1.383 Jupiter radii. Thus, the planet is larger and slightly more massive than Jupiter is. WASP-24b orbits at a distance of 0.03619 AU, roughly 3.5% of the mean distance between the Earth and Sun. It is the only planet yet discovered to orbit WASP-24.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | 1.091 ± 0.025 MJ | 0.03619 ± 0.00027 | 2.3412132 ± 0.0000018 | <0.0388 | 83.30 ± 0.30 | 1.383 ± 0.039 RJ |
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
WASP-24 is an F-type star with the hot Jupiter planet WASP-24b in orbit, about 1,075 light-years away in the constellation Virgo. WASP-24 is slightly larger and more massive than the Sun, it also has a similar metallicity and is hotter than the Sun. WASP-24 was first observed by the SuperWASP planet-searching organization, which flagged it as a potential host to a planet before following up with radial velocity and spectral measurements. Analysis of these confirmed the planetary nature of WASP-24b, which was later released to the public on the SuperWASP website. An eclipsing binary pair of companion stars were identified by a 2019 study using Gaia DR2 data. They are separated by 21.8 arcseconds from the primary star, corresponding to a distance of 7097 AU.
WASP-24b is a Hot Jupiter detected in the orbit of the F-type star WASP-24. The planet is approximately the same size and mass of Jupiter, but it orbits at approximately 4% of the mean distance between the Earth and the Sun every two days. WASP-24b was observed by SuperWASP starting in 2008; after two years of observations, follow-ups led to the collection of the information that led to the planet's discovery.
The Pratt & Whitney R-1830 Twin Wasp is an American air-cooled radial aircraft engine. It has 14 cylinders, arranged in two rings of seven. It displaces 1,830 cu in (30.0 L) and its bore and stroke are both 5.5 in (140 mm). The design traces its history to 1929 experiments at Pratt & Whitney on twin-row designs. Production began in 1932 and it was widely used during the 1930s. It was selected as the power plant for both the four-engined Consolidated B-24 Liberator heavy bomber and the twin-engined Douglas DC-3 transport, two of the most-produced aircraft. The production run of 173,618 R-1830 examples makes it the most-produced aviation engine in history. A further developed version, the R-2000, was produced starting in 1942. The R-2000 was "bored-out" to 5.75 in (146 mm) and had a number of other minor changes to improve fuel economy and allow it to run at higher power ratings on lower-octane fuel. The primary user of the R-2000 was the Douglas DC-4. Mostly retired today, the R-1830 is still used on Douglas DC-3 and various museum aircraft and warbirds seen at airshows. It is not manufactured anymore, but spares are still available and there is still a market for second-hand engines and parts.
WASP-12b is a hot Jupiter (a class of extrasolar planets) orbiting the star WASP-12, discovered in April of 2008, by the SuperWASP planetary transit survey. The planet takes only a little over one Earth day to orbit its star, in contrast to about 365.25 days for the Earth to orbit the Sun. Its distance from the star (approximately 3.5 million kilometers [2.2 million miles; 0.023 astronomical units]) is only 1 43 {\displaystyle \textstyle {\frac {1}{43}}} the Earth's distance from the Sun, with an eccentricity the same as Jupiter's. Consequently, it has one of the lowest densities for exoplanets ("inflated" by the flux of energy from the star). On December 3, 2013, scientists working with the Hubble Space Telescope (HST) reported detecting water in the atmosphere of the exoplanet. In July 2014, NASA announced finding very dry atmospheres on three exoplanets (HD 189733b, HD 209458b, WASP-12b) orbiting sun-like stars. In September 2017, researchers working on the HST announced that WASP-12b reflects just 6% of the light that shines on its surface. As a result, its reflectivity has been described as "black as asphalt" and as "pitch black", although it is so hot that it emits a reddish glow.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Shirley Chisholm, elected in 1968.
