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Movements, leaders, victories and the continuing fight for equality.
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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 | Taurus |
| Right ascension | 04h 33m 52.01440s[1] |
| Declination | +22° 50′ 30.0941″[1] |
| Apparent magnitude (V) | 13.8[2] |
| Characteristics | |
| Evolutionary stage | T Tauri star |
| Spectral type | K4IVe[2] |
| Variable type | Orion variable |
| Astrometry | |
| Radial velocity (Rv) | +16.2[2] km/s |
| Proper motion (μ) | RA: +8.942 mas/yr[1] Dec.: –17.079 mas/yr[1] |
| Parallax (π) | 6.2376±0.0205 mas[1] |
| Distance | 523 ± 2 ly (160.3 ± 0.5 pc) |
| Details | |
| Mass | 0.90±0.02[3] M☉ |
| Radius | 1.679[4] R☉ |
| Rotation | 6.6 d[5] or 9 d[6] |
| Age | 2-3[3] Myr |
| Other designations | |
| CI Tau, 2MASS J04335200+2250301, EPIC 247584113[2] | |
| Database references | |
| SIMBAD | data |
CI Tauri is a young star, about 2 million years old, located approximately 523 light-years (160 parsecs) away in the constellation Taurus. It is still accreting material from a debris disk at an unsteady pace, possibly modulated by the eccentric[7] orbital motion of an inner planet.[8] The spectral signatures of compounds of sulfur were detected from the disk.[9]
The magnetic field on the surface of CI Tauri, equal to 0.22 T, is close to average for T Tauri stars.[10]
CI Tauri hosts a protoplanetary disk, and evidence for planets has been found via both radial velocity and disk morphology.[12][6]
CI Tauri displays several periodic radial velocity variations, including periods of 6.6 days, 9 days, and 25 days.[6] The 9-day period was proposed to be due to a candidate massive planet on an eccentric orbit, CI Tauri b, in 2016.[13] The discovery of CI Tauri b was notable because it is a hot Jupiter, which are supposed to take a minimum of 10 million years to form, and are often thought to be too close to their parent stars to have formed there.[14][15]
The existence of this planet has been debated; in 2019, a detection of carbon monoxide attributed to the planet's atmosphere was announced, seemingly confirming it.[3] However, a 2020 study found that the star rotates with a period of 9 days, and suggested that the radial velocity variations may be caused by the star's rotation rather than a planet. The carbon monoxide detection was attributed to magnetic interaction of the star with the circumstellar disk.[16] Other studies have attributed the 6.6-day period to the stellar rotation and the 9-day period to the candidate planet.[8][5]
A 2024 study found evidence for a planetary origin of the 25-day radial velocity signal, while considering the 9-day signal to correspond to the stellar rotation and be caused by a starspot.[6] This 25-day candidate planet would orbit CI Tauri at a distance of 0.17 AU in a highly-eccentric orbit (e = 0.58). The mass of this planet is estimated to be 3.6±0.3 MJ.[6] While this is treated as a strong candidate and left undesignated by its discovery paper, the NASA Exoplanet Archive lists it as a confirmed planet with the designation CI Tauri c.[4] Another study in 2025 using additional observations detected the 25-day period only in the CO spectral lines, but not in atomic lines, which suggests that this periodicity is instead caused by a structure in the disk, or by a lower-mass planet orbiting at a distance of 0.16 astronomical units. The latter scenario is supported by other observations.[17]
In 2018 the possible detection of three more planets, inferred by gaps in the protoplanetary disk surrounding the star, was announced. Using the Atacama Large Millimeter Array (ALMA) to look for 'siblings' of CI Tauri b, a team of researchers detected three distinct gaps in the protoplanetary disk which their theoretical modelling suggests are caused by three other planets. The two outer planets are believed to be about the mass of Saturn, while the inner planet's mass is around the same as Jupiter.[15] Two of the new planets are similarly located to those inferred in the HL Tauri protoplanetary disk.[12]
Another 2018 study also found evidence for the outermost of these planets at around 100 AU, estimating a mass of 0.25-0.8 times that of Jupiter.[18] If this discovery is confirmed this would be the most massive collection of exoplanets ever detected at this age with its four planets spanning a factor of a thousand in orbital radius.[12]
The gaps are visible in wideband photography, but not in the gas spectral lines. These "gaps" may be lower-temperature shadows of dust in the inner disk cast on outer parts rather than true gaps carved by planets.[19]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b (false positive[4]) | 11.6+2.9 −2.7 MJ |
— | 8.9891±0.0202 | 0.25±0.16 | 50.5+6.3 −8.5° |
— |
| c (disputed[17]) | 3.6±0.3 MJ | 0.17±0.08 | 25.2+1.7 −1.8 |
0.58+0.05 −0.06 |
— | — |
| (unconfirmed) | ~0.75 MJ | ~14 | — | — | — | — |
| (unconfirmed) | ~0.15 MJ | ~43 | — | — | — | — |
| (unconfirmed) | ~0.4 MJ | ~108 | — | — | — | — |
| debris disk[9] | 200–600 AU | 50.3° | — | |||
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
CI Tauri is a young star, about 2 million years old, located approximately 523 light-years (160 parsecs) away in the constellation Taurus. It is still accreting material from a debris disk at an unsteady pace, possibly modulated by the eccentric orbital motion of an inner planet. The spectral signatures of compounds of sulfur were detected from the disk. The magnetic field on the surface of CI Tauri, equal to 0.22 T, is close to average for T Tauri stars.
Upsilon Tauri (υ Tauri) is a solitary, white-hued star in the zodiac constellation of Taurus, and is a member of the Hyades star cluster. It is faintly visible to the naked eye with an apparent visual magnitude of +4.3. Based upon an annual parallax shift of 21.21 mas seen from Earth, it is around 154 light years from the Sun.
Psi Tauri, which is Latinized from ψ Tauri, is a solitary star in the zodiac constellation of Taurus. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude of +5.22. The distance to this system, as determined using an annual parallax shift of 36.2 mas as seen from the Earth, is 91 light years. It is drifting further away with a radial velocity of +9 km/s. This object is an F-type main sequence star with a stellar classification of F1 V, which indicates it is undergoing core hydrogen fusion. It is about 1.4 billion years old and is spinning with a projected rotational velocity of 45 km/s. The star has 1.6 times the mass of the Sun and 1.4 times its radius. It is radiating 4.8 times the Sun's luminosity from its photosphere at an effective temperature of 7,088 K.
RV Tauri variables are luminous variable stars that have distinctive light variations with alternating deep and shallow minima.
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 →The Greenwood District.
