Civil Rights
Movements, leaders, victories and the continuing fight for equality.
q2K BHP
Black History Portal
THE BHP WIRE —
HIDDEN TRUTHS
What's New!
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
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
 Location and artist depiction of M51-ULS-1 | ||
| Observation data Epoch J2000.0 Equinox ICRS | ||
|---|---|---|
| Constellation | Canes Venatici | |
| Right ascension | 13h 29m 43.31s | |
| Declination | +47° 11′ 34.8″ | |
| Apparent magnitude (V) | 24.01 | |
| Characteristics | ||
| A | ||
| Evolutionary stage | Blue supergiant | |
| Spectral type | B2-8la | |
| B | ||
| Evolutionary stage | Black hole or neutron star | |
| Astrometry | ||
| Distance | 28 million ly | |
| Orbit | ||
| Primary | M51-ULS-1 A | |
| Secondary | M51-ULS-1 B | |
| Semi-major axis (a) | 50 R☉ (<3 AU) | |
| Details | ||
| A | ||
| Mass | 20 M☉ | |
| Radius | <25 R☉ | |
| Luminosity | 260,010 L☉ | |
| Temperature | 26,068 K | |
| Age | 4-16 Myr | |
| B | ||
| Mass | 1.4-10 M☉ | |
| Radius | 10[a]-30[b] km | |
| Age | 4-16 Myr | |
| Other designations | ||
| RX J132943+47115, IXO 79, CXOU J132943.3+471135 | ||
| Database references | ||
| SIMBAD | data | |
M51-ULS-1, also known as RX J132943+47115, is a high-mass X-ray binary (HMXB) system in the constellation of Canes Venatici.[1][2][3] The binary system is located in the Whirlpool Galaxy, a nearby spiral galaxy some 28 million light years (or 8.6 million parsecs) away.[1][2] The binary system has an apparent visual magnitude of 24.01.[1] The binary system was discovered in 1995 in a ROSAT survey of X-ray sources in the Whirlpool Galaxy and NGC 5195.[4]
M51-ULS-1 is a high-mass X-ray binary system in the Whirlpool Galaxy consisting of two components, a blue supergiant, and a compact object.[2][3][5] The binary system has a predicted age between 4 and 16 million years old; it was also found that the system is probably no older than 100 million years old.[3] The compact object orbits the more massive blue supergiant star in an orbit with a semi-major axis of 50 R☉, and it was found that the semi-major axis of the binary is no larger than 3 astronomical units.[3]
The primary star, M51-ULS-1 A, is a massive, luminous early to late blue supergiant star.[2][3][6] The primary star has a spectral type of B2-8la discovered using Hubble Space Telescope photometry.[3] The primary star has a mass of about 20 M☉.[2] Because of the star's mass it is predicted that the primary star might undergo a hydrogen-poor supernovae in the future.[3] The primary star has an estimated size of <25 R☉,[3][6] based on a luminosity of ~260,000 L☉[c] and a derived effective temperature of approximately 26,000 K.[3][d]
The secondary object, M51-ULS-1 B, is a stellar remnant and is either a black hole or neutron star.[2][3][5] If the secondary object is a black hole, it would have a mass of 10 M☉, classifying the secondary object as a stellar-mass black hole;[3] using its mass, it would have a Schwarzschild radius of roughly 30 kilometers.[3] If the secondary object is a neutron star, it would have mass of 1.4 M☉.[3] It is known that the secondary object is accreting 10−6 M☉ worth of material every year from the primary star.[3]
In September 2020, a candidate exoplanet named M51-ULS-1 b was discovered in the system using the Chandra X-ray Observatory.[2][3][5] The putative exoplanet is mainly notable for being the first extragalactic planet candidate with strong evidence.[2][3][5] The potential exoplanet was detected by the eclipses of the X-ray source (XRS);[3] i. e. M51-ULS-1 B, the compact object orbiting the primary star. The candidate exoplanet is likely slightly smaller than the planet Saturn.[3][7] The unconfirmed exoplanet orbits both of the objects in the system in about 70 years, and has a semi-major axis of 45 AU.[2][3][5] It was suggested that the planet could be a white dwarf, however this was ruled out because of the fact it would cause a lensing event and not a dip in flux.[3] It was also proposed that it may be a cloud of gas, however the discoverers found this as an unlikely explanation.[3] Due to M51-ULS-1 b orbiting a potential black hole it may be classified as a blanet.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | — | 45 | 70 | — | — | 0.7 RJ |
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
M51-ULS-1, also known as RX J132943+47115, is a high-mass X-ray binary (HMXB) system in the constellation of Canes Venatici. The binary system is located in the Whirlpool Galaxy, a nearby spiral galaxy some 28 million light years (or 8.6 million parsecs) away. The binary system has an apparent visual magnitude of 24.01. The binary system was discovered in 1995 in a ROSAT survey of X-ray sources in the Whirlpool Galaxy and NGC 5195.
The M51 Group is a group of galaxies located in Canes Venatici. The group is named after the brightest galaxy in the group, the Whirlpool Galaxy (M51A). Other notable members include the companion galaxy to the Whirlpool Galaxy (M51B) and the Sunflower Galaxy (M63).
LMC195-1 is a Wolf–Rayet star located in the Large Magellanic Cloud (LMC). It is an extremely rare member of the WO oxygen sequence, at WO2 the hottest known in the LMC. It is likely to be one of the hottest stars known. The star was first observed in a 2013 survey of the Magellanic Clouds using the 1 m Swope telescope at Las Campanas Observatory in Chile. The survey was intended to identify Wolf–Rayet candidate stars by taking images through narrow-bandwidth filters centred on the 465.0 nm CIII and 468.6 nm HeII spectral lines together with a continuum filter at 475.0 nm. Digital subtraction of the separate images was used to highlight stars with particularly strong emission at one or both of the indicative spectral lines. The first survey of the Large Magellanic Cloud in October 2013 identified eight previously unknown candidate objects, of which five were later confirmed to be Wolf–Rayet stars. LMC195-1 is located in the rich LH-41 (NGC 1910) stellar association that contains the luminous blue variable S Doradus as well as another WO star LH 41-1042. The two WO stars are only 9" apart. WO stars are classified on the basis of OVI emission at 381.1-383.4 nm, which is weak or absent in other Wolf–Rayet stars. The WO2 subclass is defined as having the ratio of OVI to OV emission strength between four and 12.5. Higher values would indicate WO1, while smaller values would be WO3 or WO4. In the new star, the ratio of these line strengths was 4.5.
3XMM J004232.1+411314 is a low-mass X-ray binary hosted in the galaxy M31. It is the most luminous source of hard X-rays in the Andromeda Galaxy. It is also the most luminous source known that shows dips in the X-ray light curve. The compact object in this system has been unambiguously identified as a neutron star with a spin period of 3 seconds.
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 →Brown v. Board of Education in 1954.
