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Megrez

Megrez (δ Ursae Majoris) is a single, hot main-sequence star of spectral type A3V located in the constellation Ursa Major, where it marks the junction between the bowl and handle of the Big Dipper asterism as its fifth-brightest and faintest member among the seven principal stars. With an apparent visual magnitude of 3.31, it is visible to the naked eye under dark skies and lies at a distance of 81 light-years (24.8 parsecs) from the Sun.^[1] The star has a mass of 1.63 solar masses, a radius of 1.4 solar radii, and an effective surface temperature of 9,480 K, giving it a blue-white hue.^[1] It radiates 14 times the luminosity of the Sun and rotates rapidly with a projected equatorial velocity of 233 km/s.^[1] Megrez is approximately 300 million years old and belongs to the Ursa Major Moving Group, a loose association of young stars sharing similar space velocities and originating from the same stellar formation region.^[1] It exhibits excess infrared emission suggestive of a surrounding debris disk, potentially indicating ongoing planetary formation.^[2] The name Megrez derives from the Arabic al-maghriz, translating to "the base" or "root of the tail," alluding to its position as the starting point of the Great Bear's tail in ancient Arabic astronomy.^[1] Historically, the star was cataloged by Ptolemy in the 2nd century as one of the bright stars in Ursa Major, and it has two faint visual companions of 10th and 11th magnitude separated by about 2 arcminutes, though these are not physically bound.^[3]^[1]

Location and Visibility

Coordinates and Distance

Megrez, designated Delta Ursae Majoris, occupies a prominent position within the constellation Ursa Major, forming the junction between the bowl and handle of the Big Dipper asterism, where it appears as the fifth star counting outward from the bowl's rim.^[4] In the equatorial coordinate system (J2000 epoch), its position is given by a right ascension of 12ʰ 15ᵐ 25.⁶ and a declination of +57° 01' 57".^[4] In galactic coordinates, Megrez lies at longitude 132.57° and latitude +59.42°.^[4] The star's distance from Earth is determined primarily through trigonometric parallax measurements. Data from the Gaia Data Release 3 yield a parallax of 40.3279 ± 0.1945 mas, corresponding to a distance of 24.80 ± 0.12 parsecs, or approximately 80.8 ± 0.4 light-years.^[4] This modern estimate refines earlier observations; for instance, the Hipparcos mission in 1997 measured a parallax of 40.05 ± 0.60 mas, implying a similar distance of about 81 light-years but with roughly three times the uncertainty.^[5] These parallax values enhance its utility as a navigational reference in the Big Dipper.

Apparent Magnitude and Observability

Megrez has an apparent visual magnitude of +3.31, rendering it the dimmest among the seven prominent stars forming the Big Dipper asterism in Ursa Major.^[6]^[7] This brightness level allows Megrez to be readily observable to the unaided eye in dark sky conditions from latitudes approximately 90° N to 33° S.^[8]^[9] Its position within the prominent Big Dipper makes it straightforward to locate, particularly during spring evenings when the constellation reaches its highest point in the sky for northern observers.^[10] Its absolute magnitude is approximately 1.34, derived from the apparent magnitude and Gaia DR3 distance.^[4]

Nomenclature

Traditional and Historical Names

The primary traditional name for the star now known as Megrez, or Delta Ursae Majoris, derives from the Arabic phrase al-maghriz, meaning "the base [of the bear's tail]," reflecting its position at the root of Ursa Major's tail in medieval Arabic astronomy.^[1] This nomenclature emerged during the Islamic Golden Age, when Arabic astronomers cataloged stars with descriptive terms tied to mythological or anatomical features of constellations.^[11] The name was transmitted to Western Europe through translations of Arabic texts in the 10th to 13th centuries, becoming standardized in European star atlases by the Renaissance.^[11] An alternative historical name, "Kaffa," appeared in some early 20th-century catalogs but has an uncertain origin, possibly Arabic or Persian, though no definitive etymology has been established.^[12] In Vedic astronomy, the Big Dipper's stars, including Megrez, represent the Saptarishi (Seven Sages) from Hindu scripture, with Megrez specifically associated with Atri.^[3]^[13] Chinese astronomical tradition designates the star as Běi Dǒu sì (Fourth Star of the Northern Dipper), part of the Běi Dǒu asterism symbolizing the cosmic ladle, and also as Tiān Quán (Celestial Balance), emphasizing its role in imperial calendars and feng shui alignments.^[14]

Astronomical Designations

Megrez holds the Bayer designation δ Ursae Majoris, assigned by Johann Bayer in his 1603 star atlas Uranometria, where Greek letters denote stars in order of apparent brightness within each constellation.^[15] It also bears the Flamsteed number 69 Ursae Majoris, from John Flamsteed's Historia Coelestis Britannica (1725), which numbers stars sequentially by right ascension per constellation.^[15] In the Henry Draper Catalogue, Megrez is cataloged as HD 106591, a comprehensive 20th-century survey classifying nearly 225,000 stars by spectral type.^[15] The Bright Star Catalogue lists it as HR 4660, providing detailed parameters for the brightest naked-eye stars.^[15] Additional identifiers include SAO 28315 from the Smithsonian Astrophysical Observatory Star Catalog, which maps positions for over 258,000 stars; BD+57 1363 from the Bonner Durchmusterung, a 19th-century all-sky survey north of the equator; and HIP 59774 from the Hipparcos Catalogue, based on astrometric observations from the 1989–1993 Hipparcos mission.^[15] Megrez is included in the SIMBAD astronomical database, aggregating multi-wavelength data from various observatories for coordinated research.^[15] It also appears in Gaia Data Release 3 (DR3) as Gaia DR3 1575287046603605888, offering high-precision parallax, proper motion, and photometric measurements from the European Space Agency's Gaia mission.^[16] The traditional name Megrez was approved as the proper name by the International Astronomical Union's Working Group on Star Names in 2016.^[17]

Stellar Characteristics

Physical Parameters

Megrez is an A-type main-sequence dwarf star classified as A2 Vn.^[8] Its mass is estimated at 2.062 ± 0.033 solar masses (M⊙), placing it among the more massive stars on the main sequence.^[18] The star's luminosity is 23 ± 1 solar luminosities (L⊙), reflecting its elevated energy output compared to solar-type stars.^[18] The effective radius of Megrez is approximately 2.4 solar radii (R⊙), consistent with models of rapidly rotating A-type stars.^[18] Age estimates derived from isochrone fitting indicate that Megrez is 414 ± 43 million years old, positioning it in the mid-main-sequence phase, well past the zero-age main sequence but prior to the turnoff point.^[18] This evolutionary stage aligns with its membership in the Ursa Major moving group, where stellar parameters support a coherent formation history.^[18]

Spectrum and Atmosphere

Megrez exhibits a spectrum typical of an A-type main-sequence star, classified as A2Vn based on high-resolution spectroscopic analysis. The defining feature is the prominent Balmer series of hydrogen absorption lines, which reach maximum strength in early A-type stars due to the ionization balance at these temperatures. Helium lines are visible but weaker than in hotter B-type stars, while metal lines from elements such as iron and magnesium appear subdued, reflecting the star's mildly depleted heavy-element content relative to solar abundances. The star's atmosphere is characterized by an effective temperature of 8298 K, yielding a blue-white hue with a B-V color index of +0.09. This temperature places Megrez in the regime where hydrogen is partially ionized, contributing to the sharp Balmer lines observed across the optical spectrum. Metallicity measurements indicate [Fe/H] ≈ -0.44, classifying it as slightly metal-poor, which results in reduced opacity from metallic absorption and correspondingly fainter metal lines compared to solar-metallicity counterparts. Surface gravity is log g ≈ 3.94 (cgs units), confirming its status as a dwarf on the main sequence with a stable, hydrostatic atmospheric structure. Given its high effective temperature, Megrez's envelope features a thin convective zone, limited to shallow layers near the surface where ionization of hydrogen and helium creates localized instability. The bulk of the energy transport occurs radiatively, with convection confined due to the low opacity and steep temperature gradient in the outer layers. This structure is consistent with models of A-type stellar atmospheres, where the convective envelope thickness is typically less than 1% of the stellar radius.^[19]

Rotation and Oblateness

Megrez exhibits rapid rotation, characterized by a projected rotational velocity v sin i = 233 ± 12 km/s measured through high-resolution spectroscopy and an equatorial velocity v_eq ≈ 310 km/s from interferometric modeling, implying an inclination of approximately 48°.^[18] This corresponds to a rotation period of approximately 10 hours. The fast rotation distorts Megrez into an oblate spheroid, with an equatorial radius of 2.512 R_⊙ and a polar radius of 1.921 R_⊙, corresponding to a flattening of about 24%. This shape arises from centrifugal forces counteracting gravity, particularly notable given the star's mass of roughly 2 M_⊙.^[18] Rotation also induces gravity darkening, resulting in a temperature differential across the stellar surface: 6,909 K at the equator and 10,030 K at the poles. These effects highlight how rapid rotation influences the star's photospheric properties.^[18] Measurements of these parameters rely on complementary techniques. Spectroscopy provides the projected rotation velocity by analyzing line broadening in the star's spectrum. Interferometry, using the CHARA Array as detailed in the Ages of A-Stars study, spatially resolves the stellar disk to model oblateness, radii, and temperature gradients through Roche potential approximations and visibility fitting.^[18]

Stellar System

Companion Stars

Megrez is accompanied by two faint visual companions, designated δ Ursae Majoris B and δ Ursae Majoris C, with apparent magnitudes of approximately 10 and 11, respectively. These stars are positioned at angular separations of approximately 3 arcminutes from the primary, placing them well outside the resolution of small telescopes but observable with moderate apertures.^[20] The companions were first documented in 19th-century astronomical surveys, with the initial systematic measurement recorded in 1878. Modern observations in the Washington Double Star Catalog list position angles around 73° and separations near 181–192 arcseconds for δ UMa B, based on 17 measurements spanning over a century. δ UMa C shows a similar configuration at roughly 186 arcseconds.^[21] Astrometric data indicate that both companions exhibit proper motions closely matching that of the primary star (approximately +104 mas/yr in right ascension and +7 mas/yr in declination), which supports the possibility of a physical connection within the Ursa Major moving group. However, at Megrez's distance of 80.5 light-years, the angular separations translate to projected physical distances exceeding 1000 AU, rendering any potential orbit extremely wide or suggesting they may be unbound field stars aligned by chance.

Circumstellar Debris Disk

A circumstellar debris disk surrounds Megrez, detected via an infrared excess in observations from the Spitzer Space Telescope at 24 μm and 70 μm wavelengths. This excess emission, indicative of thermal radiation from dust grains, was further probed by the Herschel Space Observatory during the DEBRIS survey, confirming the presence of cool dust at longer wavelengths including 100 μm and 160 μm.^[22] The disk orbits at a radius of approximately 44.8 AU, comparable to beyond the location of the Solar System's outer planets and suggesting a region of planetesimal concentration.^[22] Modeling of the emission indicates that the dust consists of cool grains with a blackbody temperature of 115 ± 5 K, consistent with equilibrium under stellar heating, a fractional luminosity of 1.35 ± 0.27 × 10^{-5}, and a total dust mass on the order of 0.01 Earth masses.^[23]^[22] The observed infrared excess points to ongoing production of dust through collisions between planetesimals in the disk, rather than primordial material. No planets have been confirmed around Megrez, though the disk's structure implies a dynamically stable environment conducive to such collisions. The disk's continued visibility at an age of approximately 414 million years implies relatively low levels of dynamical excitation, such as from massive planets, allowing the dust to persist without rapid clearing.^[24]

Kinematics and Evolution

Proper Motion and Space Velocity

Megrez displays a proper motion across the sky of μ_α = +103.7 mas/yr in right ascension and μ_δ = +9 mas/yr in declination, based on Hipparcos astrometry integrated with ground-based radial velocity measurements. These values indicate a relatively modest annual shift in position, consistent with the star's membership in a nearby stellar association. Recent Gaia observations refine this to μ_α = +103.95 ± 0.18 mas/yr and μ_δ = +8.14 ± 0.18 mas/yr, confirming the overall direction and scale of motion with higher precision. The radial velocity of Megrez is -20.2 km/s, signifying approach toward the Solar System at that speed. Updated Gaia spectroscopic data report a value of -12.4 ± 0.8 km/s, reflecting improved measurement accuracy from longer baseline observations. The tangential velocity, derived from the proper motion and a parallax of 40.05 mas (corresponding to a distance of approximately 25 pc), is about 12 km/s. This component captures the star's motion perpendicular to the line of sight, contributing to its gradual displacement relative to background stars over human timescales. In galactic coordinates, Megrez's space velocity components relative to the Sun are U = +15.4 km/s (directed toward the galactic center), V = +1.2 km/s (in the direction of galactic rotation), and W = -11.5 km/s (toward the north galactic pole). These values place the star within the kinematic signature of the Ursa Major moving group, where members share similar velocity vectors tracing back to a common dynamical origin. The total space velocity magnitude is roughly 19 km/s, underscoring Megrez's coherent motion through the solar neighborhood as part of this association.

Age and Moving Group Membership

Megrez, an A3 V star, has an estimated age of 414 ± 35 Myr, derived from stellar isochrone models that account for its observed luminosity, effective temperature, and metallicity using the Modules for Experiments in Stellar Astrophysics (MESA) code.^[24] These models incorporate rotational effects, such as gravity darkening, informed by interferometric observations of the star's oblateness. For A-type stars like Megrez, lithium depletion is not a reliable age indicator due to their radiative atmospheres, which prevent significant convective mixing of lithium into deeper layers.^[24] However, lithium abundances in the cooler G- and K-type members of its associated moving group provide supporting evidence for a young age, with depletions consistent with 300–500 Myr of evolution on the main sequence. Megrez is a confirmed member of the Ursa Major Moving Group (UMa MG), a nearby association of stars sharing common kinematics, as evidenced by its space velocity aligning with the group's convergent point and mean motion.^[24] Membership was established through a combination of spectroscopic measurements of radial velocity and projected rotation, alongside astrometric data on proper motion and parallax from Hipparcos, with subsequent confirmation from Gaia astrometry enhancing the precision of these kinematic matches.^[24] The UMa MG itself has an age of approximately 400–500 Myr, determined consistently across multiple A-type members using similar isochrone fitting, placing it as a post-T Tauri group younger than the Hyades but older than the Pleiades.^[24] The coeval nature of UMa MG stars, including Megrez, suggests they formed from the same molecular cloud complex before dispersing due to galactic tidal forces, resulting in a chemically homogeneous population with near-solar metallicity (Z = 0.016).^[24] This shared origin implies minimal differential chemical evolution, as confirmed by spectroscopic analyses showing uniform iron abundances across group members.^[24] Such homogeneity aids in refining age estimates and understanding the group's dynamical history within the local interstellar medium.

Historical and Cultural Context

Early Observations and Cataloging

Megrez, known today as Delta Ursae Majoris, was first recognized in ancient astronomical records as part of the constellation Ursa Major, cataloged by Claudius Ptolemy in his second-century Almagest. Ptolemy described Ursa Major with 27 stars in the constellation figure, rating Megrez with a magnitude of 3, noting its position at the base of the bear's tail.^[25] This early inclusion highlighted its visibility and role within the prominent asterism now called the Big Dipper, though Ptolemy's observations relied on naked-eye measurements without telescopic aid.^[26] In Arabic astronomy, the star was known as Al Meghrez, derived from al-maghriz meaning "the root" or "base of the tail," emphasizing its anatomical position in the bear figure; this name was later shortened to Megrez and formally approved by the International Astronomical Union in 2016.^[1] The 10th-century Persian astronomer Abd al-Rahman al-Sufi's Book of Fixed Stars, an influential update to Ptolemy's work, incorporated Arabic star names and illustrations of constellations viewed from both earthly and celestial perspectives, preserving and expanding Ptolemaic data with improved positional accuracy based on his own observations at the Buyid court observatory in Isfahan. The star received its modern Greek-letter designation in 1603 when Johann Bayer included it as Delta Ursae Majoris in his seminal star atlas Uranometria, which systematically labeled stars within constellations using letters from the Greek alphabet, often in order of brightness or position rather than strict magnitude.^[27] Bayer's work marked a key advancement in stellar cartography, compiling data from earlier observers like Tycho Brahe, who had rated Megrez brighter at magnitude 2, and facilitating more precise mapping for future astronomers.^[25] By the 19th century, Megrez appeared in major systematic catalogs that refined positions and noted potential companions. It was included in the Preliminary General Catalogue of 6188 Stars (1910) compiled by Lewis Boss at Dudley Observatory, which provided equatorial coordinates and proper motions for epoch 1900 based on meridian circle observations.^[17] Earlier, in the 1820s–1830s, Friedrich Georg Wilhelm von Struve documented faint companions near Megrez during his pioneering surveys of double stars at Dorpat Observatory, listing it among thousands of pairs in his Mensa Astronomica (1827) and subsequent catalogs to investigate orbital dynamics. Prior to telescopic observations, Megrez served a practical role in pre-telescopic navigation as a marker in the Big Dipper asterism of Ursa Major, which ancient mariners and travelers used to locate Polaris by extending a line from the stars Dubhe and Merak, a method attributed to Greek philosopher Thales of Miletus around 600 BCE for determining northern directions at sea.^[28] This asterism's circumpolar visibility in the Northern Hemisphere made it a reliable guide for orientation in various cultures long before formal cataloging.^[29]

Mythological and Cultural Significance

In Greek and Roman mythology, Megrez forms part of the constellation Ursa Major, depicted as the great bear transformed from the nymph Callisto, a companion of Artemis who was seduced by Zeus and subsequently changed into a bear by the jealous Hera to prevent her from remaining beautiful.^[30] This tale is detailed in Ovid's Metamorphoses, where Callisto's son Arcas nearly hunts her unknowingly, leading Zeus to place both mother and son among the stars as Ursa Major and Ursa Minor to ensure their eternal safety.^[31] The Big Dipper asterism, including Megrez as one of its stars, was sometimes interpreted separately as a wagon drawn by oxen, symbolizing agricultural cycles in Roman lore.^[31] Among Native American cultures, Megrez contributes to the Big Dipper's portrayal as a celestial bear pursued by hunters, a motif prominent in Iroquois traditions where the bowl stars represent the bear and the handle stars the pursuing warriors, embodying themes of seasonal renewal as the bear is "killed" in autumn and revives in spring.^[32] This narrative, recorded in Harriet Maxwell Converse's Myths and Legends of the New York State Iroquois (1908), underscores the bear's role in teaching perseverance and the cyclical nature of life.^[32] Similarly, in Mi'kmaq lore, the Big Dipper depicts a great bear (muin) chased across the sky by seven hunters, with the bowl as the bear's body and the handle as the closest pursuers, serving as a moral tale about endurance and the stars' guidance for earthly hunters. In Chinese cosmology, particularly within Taoism, the Northern Dipper (Beidou), encompassing Megrez as one of its seven stars, symbolizes cosmic balance and the administration of fate, believed to oversee human destiny, longevity, and the harmony of yin and yang. Taoist rituals, such as bugang or "pacing the stars," involve practitioners tracing the Dipper's pattern to invoke its powers for protection and immortality, reflecting its central role in aligning earthly actions with celestial order.^[33] The asterism's rotation around Polaris was seen as a divine chariot or ladle distributing the elixir of life, reinforcing themes of eternal cycles in Daoist philosophy.^[34] Megrez's position in the Plough asterism of the Big Dipper has long aided navigation, particularly in finding Polaris by extending a line from the pointer stars Dubhe and Merak, enabling travelers to determine true north across hemispheres.^[29] This utility ties into seasonal bear-hunting myths in various cultures, where the Dipper's apparent motion mimics a bear fleeing southward in fall, only to return north in spring, guiding seasonal migrations and agricultural timing.^[31] In Hindu tradition, Megrez is associated with the rishi Atri, one of the Saptarishi or seven sages mapped to the Big Dipper stars, representing wisdom and Vedic hymns in ancient Indian astronomy.^[35] In modern culture, Megrez as part of the Big Dipper appears in literature and art symbolizing guidance and aspiration, such as in African American spirituals like "Follow the Drinking Gourd," where the asterism directs enslaved people northward to freedom.^[36] Visual artists like Jackson Pollock evoked its form in Reflections of the Big Dipper (1947), using dripped enamel to capture cosmic motion and introspection.^[37]

Namesakes

Military and Nautical

The USS Megrez (AK-126) was a Crater-class cargo ship commissioned by the United States Navy during World War II, named after Megrez (δ Ursae Majoris), a star in the constellation Ursa Major.^[38] Originally laid down as the Liberty ship SS George Weems on 3 March 1943 at the California Shipbuilding Corp. in Wilmington, California, she was launched on 23 April 1943, acquired by the Navy on 7 October 1943, and renamed Megrez on 11 October 1943.^[38] After conversion at Bethlehem Steel Co. in San Francisco, she was commissioned on 26 October 1943 under the command of Lieutenant Commander James E. Dow, USNR.^[38] Throughout her service in the Pacific Theater, Megrez provided essential logistical support, departing San Francisco on 13 November 1943 with a cargo of ammunition and explosives.^[38] She operated from Funafuti in the Ellice Islands until 6 March 1944, then shifted to Kwajalein in the Marshall Islands to aid fleet operations following the U.S. conquest of the atoll.^[38] Arriving at Pearl Harbor on 2 June 1944, she subsequently supported the invasions of Saipan and Tinian, reaching the latter on 14 August 1944.^[38] From Ulithi between 14 October 1944 and 13 April 1945, Megrez delivered supplies, including lube oil, to the Third and Fifth Fleets; she later served at Palau from 14 April 1945, in the Philippines from 18 April to 5 October 1945, at Okinawa from 13 October 1945, and in Japan from 7 November 1945.^[38] After the war, Megrez returned to Pearl Harbor, where she was decommissioned on 29 May 1946 and placed in reserve.^[38] She was stricken from the Naval Vessel Register on 1 August 1947 and ultimately sold for scrapping on 13 June 1974 to Zidell Explorations, Inc., at Suisun Bay, California.^[38] In maritime contexts, the name Megrez has appeared on several modern commercial vessels, including the Italian-registered tug Megrez (IMO 9334911), built in 2005 and measuring 31.3 meters in length, used for harbor operations.^[39] Another example is the LNG carrier LNG Megrez, delivered in 2020 as part of the Yamal LNG project, a 174,000 cubic meter vessel operated by Mitsui O.S.K. Lines for Arctic gas transport.^[40] These namings draw from the star's traditional designation in celestial navigation aids, though Megrez itself is not among the primary 57 stars listed in modern nautical almanacs.^[41]

Scientific and Other

In astronomy, the name Megrez has been adopted for several optical instruments. William Optics, a Taiwanese manufacturer of high-end telescopes, produces a series of apochromatic refractors under the Megrez designation, including models such as the Megrez 72 FD (72 mm aperture, f/6 focal ratio) and Megrez 90 (90 mm aperture, f/5.8 focal ratio), prized for their compact design and suitability for wide-field astrophotography and visual observation.^[42] Similarly, OtO Photonics offers the Megrez series of cooled high-resolution spectrometers, which operate across the 400–1000 nm wavelength range and are used for precise spectral analysis in laboratory and astronomical applications.^[43] In science fiction, Megrez appears as a named star system in the Star Trek universe, depicted as a trinary system in the Alpha Quadrant with the primary being an F-type star; it is referenced in episodes and expanded media, including the USS Megrez, a Federation repair ship.^[44] The name also features in the BattleTech franchise as Megrez, a habitable planet in the Lyran Commonwealth, central to conflicts during the Third Succession War.^[45] Additionally, in the Shin Megami Tensei: Devil Survivor 2 video game, Megrez is one of the Septentriones, antagonistic entities inspired by the stars of Ursa Major, manifesting as a destructive force tied to the constellation's mythology.^[46]

References

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Reflection of the Big Dipper consists of built-up layers of paint with dripped enamel as the final touch, concluding the composition.
[37]
Megrez (AK-126) - Naval History and Heritage Command
Jan 7, 2025 · Named for Megrez, a third-magnitude star, the fourth-brightest star in the constellation Ursa Major (Big Dipper). General Vallejo was laid down ...Missing: etymology | Show results with:etymology
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Ship MEGREZ (Tug) Registered in Italy - Vessel details, Current ...
MEGREZ (IMO: 9334911) is a Tug and is sailing under the flag of Italy. Her length overall (LOA) is 31.3 meters and her width is 10 meters.Missing: named | Show results with:named
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The last LNG carrier of four built in China for the project
Oct 21, 2020 · The vessel is the last of four newbuilding conventional LNG Carriers for the Yamal LNG Project announced at the end of June 2017 *1, and was named LNG MEGREZ.
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Navigational Star Chart - Astronomical Applications Department
This chart displays constellations and the 57 navigational stars used in the Air and Nautical Almanacs.Missing: Megrez | Show results with:Megrez
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https://aa.usno.navy.mil/data/Nav_Star_Chart
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Megrez Cooled Hi Res 400-1000nm - AP Technologies
Megrez-series spectrometers from OtO Photonics are high resolution models covering the wavelength range 400nm to 1000nm.
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Megrez | Memory Alpha | Fandom
It was one of the dimmest stars in its constellation and was approximately 81 light years from Sol. This star system was only mentioned in writing.
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Megrez - BattleTechWiki - Sarna.net
Feb 12, 2025 · At some point in the Third Succession War, the Lyran Commonwealth seized Megrez from the Free Worlds League. When Janos Marik ordered an assault ...
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Megrez | Megami Tensei Wiki | Fandom
Megrez arrives on Wednesday and is the fourth Septentrione to appear, first appearing in the Pacific Ocean and spreading the prismatic human-sized buds.