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GREENWOOD / BLACK WALL STREET WILMINGTON 1898 LITTLE ROCK NINE TUSKEGEE STUDY ROSEWOOD 1923 THE TUSKEGEE AIRMEN SENECA VILLAGE BLACK TOWNS GREENWOOD / BLACK WALL STREET WILMINGTON 1898 LITTLE ROCK NINE TUSKEGEE STUDY ROSEWOOD 1923 THE TUSKEGEE AIRMEN SENECA VILLAGE BLACK TOWNS
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MY'STORY

The MOVE Fire

This is a personal recollection on the Move fire on May 13, 1985 Philadelphia police fired thousands of rounds at the MOVE house, city officials approved dropping an explosive device on the roof, the resulting fire was allowed to burn, 11 people—including five children—died, and 61 homes were destroyed. Philadelphia City Council later called it a “brutal attack carried out by the City of Philadelphia on its own citizens” and acknowledged that no individual faced criminal consequences for the bombing. One timeline correction worth preserving for the BHP record: the major previous MOVE-police confrontation was August 8, 1978, about seven years before the bombing, not a year or two earlier. Officer James Ramp was killed, other police and firefighters were wounded, nine MOVE members were later convicted, and television cameras recorded police beating Delbert Africa during his arrest. The 1985 MOVE Commission later specifically criticized city planners for failing to adequately use lessons from that 1978 confrontation. And that actually strengthens the point you’re making: 1985 did not happen without precedent or institutional memory. There had already been a deadly confrontation with MOVE, years of conflict, negotiations and police involvement before Osage Avenue.

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BLACK FACTS
The Truths They Never Taught You...

The Violence That Helped Spark the NAACP

In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.

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Wikipedia

Gamma Sextantis

γ Sextantis
Location of γ Sextantis (circled in red)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 09h 52m 30.43727s[1]
Declination −08° 06′ 18.1269″[1]
Apparent magnitude (V) 5.05[2] (5.6 + 6.0)[3]
Characteristics
Evolutionary stage main sequence[4]
Spectral type A0/1 V[5] (A1 V + A4 V)[6]
U−B color index +0.06[2]
B−V color index +0.04[2]
Astrometry
Radial velocity (Rv)+12[7] km/s
Proper motion (μ) RA: −57.28[1] mas/yr
Dec.: −49.26[1] mas/yr
Parallax (π)11.75±0.63 mas[1]
Distance280 ± 10 ly
(85 ± 5 pc)
Absolute magnitude (MV)+0.43[8]
Orbit[9]
Period (P)77.61±0.59 yr
Semi-major axis (a)0.380±0.013″
Eccentricity (e)0.741±0.019
Inclination (i)143.2±3.4°
Longitude of the node (Ω)198.5±5.2°
Periastron epoch (T)1956.84±0.69
Argument of periastron (ω)
(secondary)		306.2±6.5°
Details
Mass2.60[10] M☉
Radius3.2[11] R☉
Luminosity69[4] L☉
Surface gravity (log g)4.18±0.14[10] cgs
Temperature9,825±334[10] K
Rotational velocity (v sin i)134.6±1.4[12] km/s
Age401[10] Myr
Other designations
γ Sex, 8 Sextantis, BD−07°2909, HD 85558, HIP 48437, HR 3909, SAO 137199.[13]
Database references
SIMBADdata

Gamma Sextantis, Latinized as γ Sextantis, is a binary star[14] system in the equatorial constellation of Sextans. The combined apparent visual magnitude of the system is 5.05,[2] which means it is faintly visible to the naked eye. The annual parallax shift is 11.75 mas,[1] indicating a distance of around 280 light years.

The two components orbit each other with a period of 77.6 years and a high eccentricity of 0.741. The orbital plane is inclined by 143.2° to the line of sight from the Earth.[9] With a visual magnitude of 5.6,[6] the brighter component Gamma Sextantis A is an A-type main sequence star with a stellar classification of A1 V.[6] The fainter companion Gamma Sextantis B has a classification of A4 V[6] with a magnitude of 6.0.[6] Their combined spectrum matches a classification of A0/1 V.[5] Their angular separation 0.4 arcseconds, so observation with a telescope requires a diameter of at least 30 centimeters.[citation needed]

There is a magnitude 12.28 companion star Gamma Sextantis C at an angular separation of 36.9 arc seconds along a position angle of 333°, as of 2000. This separation has increased from 30.0 arc seconds in 1834. The proper motion of this star differs from the Gamma Sextantis AB system, having proper motions of −29 mas/yr and +5 mas/yr in right ascension and declination, respectively.[15]

References

[edit]
  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. ^ Heintz, W. D. (March 1982), "Orbits of 16 visual binaries", Astronomy and Astrophysics Supplement Series, 47: 569–573, Bibcode:1982A&AS...47..569H.
  4. ^ a b Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  5. ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, Bibcode:1999MSS...C05....0H.
  6. ^ a b c d e Edwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal, 81: 245–249, Bibcode:1976AJ.....81..245E, doi:10.1086/111879.
  7. ^ Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  8. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  9. ^ a b Tokovinin, Andrei; Mason, Brian D.; Mendez, Rene A.; Costa, Edgardo (July 2024), "Speckle Interferometry at SOAR Telescope in 2023", The Astronomical Journal, 168 (1): 28, Bibcode:2024AJ....168...28T, doi:10.3847/1538-3881/ad4d56, ISSN 0004-6256.
  10. ^ a b c d David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  11. ^ McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433.
  12. ^ Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv:1012.4858, Bibcode:2011A&A...531A.143D, doi:10.1051/0004-6361/201016386, S2CID 119286673.
  13. ^ "gam Sex – Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-14.
  14. ^ Eggleton, P. P.; et al. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  15. ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.

Source: Wikipedia. Article content is retrieved live through the MediaWiki API.

Wikipedia

Gamma Sextantis

Gamma Sextantis, Latinized as γ Sextantis, is a binary star system in the equatorial constellation of Sextans. The combined apparent visual magnitude of the system is 5.05, which means it is faintly visible to the naked eye. The annual parallax shift is 11.75 mas, indicating a distance of around 280 light years. The two components orbit each other with a period of 77.6 years and a high eccentricity of 0.741. The orbital plane is inclined by 143.2° to the line of sight from the Earth. With a visual magnitude of 5.6, the brighter component Gamma Sextantis A is an A-type main sequence star with a stellar classification of A1 V. The fainter companion Gamma Sextantis B has a classification of A4 V with a magnitude of 6.0. Their combined spectrum matches a classification of A0/1 V. Their angular separation 0.4 arcseconds, so observation with a telescope requires a diameter of at least 30 centimeters. There is a magnitude 12.28 companion star Gamma Sextantis C at an angular separation of 36.9 arc seconds along a position angle of 333°, as of 2000. This separation has increased from 30.0 arc seconds in 1834. The proper motion of this star differs from the Gamma Sextantis AB system, having proper motions of −29 mas/yr and +5 mas/yr in right ascension and declination, respectively.

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Wikipedia

Gamma Geminorum

Gamma Geminorum (γ Geminorum, abbreviated Gamma Gem, γ Gem), formally named Alhena , is the third-brightest object in the constellation of Gemini. It has an apparent visual magnitude of 1.9, making it easily visible to the naked eye even in urban regions. Based upon parallax measurements with the Hipparcos satellite, it is located at a distance of roughly 109 light-years (33 parsecs).

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Wikipedia

7 Sextantis

7 Sextantis is an early A-type star in the constellation Sextans. The star has a relatively large proper motion and high radial velocity and is catalogued as a high proper motion star in astronomical databases. Because of its unusual kinematics, it has been interpreted either as a possible runaway star ejected from the Scorpius-Centaurus association or as an evolved object belonging to the old Galactic disk.

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Wikipedia

Slowly pulsating B-type star

A slowly pulsating B-type star (SPB), formerly known as a 53 Persei variable, is a type of pulsating variable star. They may also be termed a long-period pulsating B star (LPB). As the name implies, they are main-sequence stars of spectral type B2 to B9 (3 to 9 times as massive as the Sun) that pulsate with periods between approximately half a day and five days, however within this most member stars have been found to have multiple periods of oscillations. They display variability both in their light emission and in their spectral line profile. The variations in magnitude are generally smaller than 0.1 magnitudes, making it quite hard to observe variability with the naked eye in most cases. The variability increases with decreasing wavelength, thus they are more obviously variable in ultraviolet spectrum than visible light. Their pulsations are non-radial, that is, they vary in shape rather than volume; different parts of the star are expanding and contracting simultaneously. These stars were first identified as a group and named by astronomers Christoffel Waelkens and Fredy Rufener in 1985 while looking for and analysing variability in hot blue stars. Improvements in photometry had made finding smaller changes in magnitude easier, and they had found that a high percentage of hot stars were intrinsically variable. They referred to them as 53 Persei stars after the prototype 53 Persei. Ten had been discovered by 1993, though Waelkens was unsure if the prototype was actually a member and recommended referring to the group as slowly pulsating B (SPB) stars. The General Catalogue of Variable Stars uses the acronym LPB for "comparatively long-period pulsating B stars (periods exceeding one day)", although this terminology is rarely seen elsewhere. The similar Beta Cephei variables have shorter periods and have p-mode pulsations, while the SPB stars show g-mode pulsations. By 2007, 51 SPB stars had been confirmed with another 65 stars possible members. Six stars, namely Iota Herculis, 53 Piscium, Nu Eridani, Gamma Pegasi, HD 13745 (V354 Persei) and 53 Arietis had been found to exhibit both Beta Cephei and SPB variability.

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TOPIC OF THE DAY

Greenwood / Black Wall Street

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.

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TRIVIA QUESTION OF THE DAY

Who became the first Black woman to travel into space?

Mae Jemison, aboard Space Shuttle Endeavour in 1992.