"general relativity was proposed, and ""vigorous debate"" ensued until August 2012 when the IAU adopted the current definition of 1 astronomical unit = metres. The astronomical unit is typically used for stellar system scale distances, such as the size of a protostellar disk or the heliocentric distance of an asteroid, whereas other units are used for other distances in astronomy. The astronomical unit is too small to be convenient for interstellar distances, where the parsec and light-year are widely used. The parsec (parallax arcsecond) is defined in terms of the astronomical unit, being the distance of an object with a"
"26 Andromedae 26 Andromedae, abbreviated 26 And, is an astrometric binary star system in the constellation Andromeda. ""26 Andromedae"" is the Flamsteed designation. It has a combined apparent visual magnitude of 6.10, which is near the lower limit of visibility to the naked eye. The distance to this system can be estimated from its annual parallax shift of , which yields a range of 610 light years. At that distance, the visual magnitude of the stars is diminished from an extinction of 0.04 due to interstellar dust. The system is moving further from the Earth with a heliocentric radial velocity"
"26 Draconis 26 Draconis is a triple star system in the constellation Draco, located 46 light years from the Sun. Two of the system components, A and B, form a spectroscopic binary that completes an orbit every 76 years. The composite spectral classification of the AB pair is G0V, which decomposes to individual spectral types F9V and K3V. A 1962 study estimated the masses of these two stars as 1.30 and 0.83 times the mass of the Sun, respectively. The stars are considered moderately metal-poor compared to the Sun, which means they have a lower proportion of elements other than"
"the plane of the galactic disk. This system may be a member of the Ursa Major moving group. 26 Draconis 26 Draconis is a triple star system in the constellation Draco, located 46 light years from the Sun. Two of the system components, A and B, form a spectroscopic binary that completes an orbit every 76 years. The composite spectral classification of the AB pair is G0V, which decomposes to individual spectral types F9V and K3V. A 1962 study estimated the masses of these two stars as 1.30 and 0.83 times the mass of the Sun, respectively. The stars are"
"lower limit ""inferred through observing the far-UV absorption by the low-z IGM."" 3C 66A underwent an optical outburst in 2007 August, as monitored by the Tuorla blazar monitoring program. The event was monitored by the Whole Earth Blazar Telescope project. 3C 66A 3C 66A is a blazar located in the constellation Andromeda. The ""distance"" of a far away galaxy depends on what distance measurement you use. With a redshift of 0.444, light from this active galaxy is estimated to have taken around 4.5 billion years to reach us. But as a result of the expansion of the Universe, the present"
"26 Aquilae 26 Aquilae (abbreviated 26 Aql) is a binary star system in the equatorial constellation of Aquila. ""20 Aquilae"" is its Flamsteed designation though it also bears the Bayer designation f Aquilae. It has an apparent visual magnitude of 5.00, which means it is faintly visible to the naked eye. As the Earth orbits the Sun, this star system undergoes a parallax shift of 21.15 mas. This means it is located at a distance of approximately from Earth, give or take a 3 light-year margin of error. This is a single-lined spectroscopic binary system, meaning that the presence of"
"3C 66A 3C 66A is a blazar located in the constellation Andromeda. The ""distance"" of a far away galaxy depends on what distance measurement you use. With a redshift of 0.444, light from this active galaxy is estimated to have taken around 4.5 billion years to reach us. But as a result of the expansion of the Universe, the present (co-moving) distance to this galaxy is about 5.4 billion light-years (1647 Mpc). Even at this great distance this blazar has an apparent magnitude of about 15.5. Although 0.444 is used as the common redshift value, 0.3347 is a new strict"
"36 Andromedae 36 Andromedae is a visual binary star system in the northern constellation of Andromeda. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. It is faintly visible to the naked eye with an apparent visual magnitude of 5.45. An annual parallax shift of 26.33 mas yields a distance estimate of about 124 light years. The system is moving closer to the Sun with a radial velocity of −0.8 km/s. The binary nature of this system was discovered in 1832 by the German-Russian astronomer Wilhelm von Struve. It is a wide binary"
"36 Andromedae 36 Andromedae is a visual binary star system in the northern constellation of Andromeda. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. It is faintly visible to the naked eye with an apparent visual magnitude of 5.45. An annual parallax shift of 26.33 mas yields a distance estimate of about 124 light years. The system is moving closer to the Sun with a radial velocity of −0.8 km/s. The binary nature of this system was discovered in 1832 by the German-Russian astronomer Wilhelm von Struve. It is a wide binary"
"NGC 3726 NGC 3726 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 3726 is about 85,000 light years across. It was discovered by William Herschel οn February 5, 1788. NGC 3726 is a spiral galaxy with a small bar, seen with medium inclination. The bar is 1.38 arcseconds across and it ends at an inner ring with 1.50 arcseconds diametre. The bluest regions of star formation are located at the ring. Three arms emmanate from the"
"2M 1237+6526 2MASS J12373919+6526148 (hereafter 2M 1237+6526) is a brown dwarf object with late spectral type T in the constellation of Draco, nearly 46 light years away from Sun. The substellar object could likely host a very low-mass companion (yet undetected but inferred), possibly in planetary regime. Burgasser et al. (2003) have inferred the presence of a low-mass companion orbiting the brown dwarf 2M 1237+6526. Such object would yield a mass between 3 and 12 times that of Jupiter and take nearly 4.56 hours (0.19 days) to revolve around its dim primary. If confirmed it would be the shortest period"
"1998 KY26 KY26 orbits the Sun at a distance of 1.0–1.5 AU once every 16 months (500 days). Its orbit has an eccentricity of 0.20 and an inclination of 1° with respect to the ecliptic. It has an Earth minimum orbital intersection distance of , which translates into 0.93 lunar distances. As a result, KY26 is one of the most easily accessible objects in the Solar System, and its orbit frequently brings it on a path very similar to the optimum Earth–Mars transfer orbit. This, coupled with the fact that it is water-rich, makes it an attractive target for further"
"NGC 4026), UGC 6922 (26 arcminutes from NGC 4026) and UGC 6956 (10 arcminutes from NGC 4026). NGC 4026 appears disturbed in HI imaging, with a filament extending southward. The mass of HI in NGC 4026 is below 0.71 × 10 M⊙. The total HI mass in NGC 4026, UGC 6956 and the HI filament is estimated to be 7.94 × 10 M⊙. NGC 4026 NGC 4026 is a lenticular galaxy in the constellation Ursa Major. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 4026 is"
"NGC 3626 NGC 3626, also Caldwell 40, is a medium-tightness spiral galaxy and Caldwell object in the constellation Leo. It was discovered by William Herschel, on 14 March 1784. It shines at magnitude +10.6/+10.9. Its celestial coordinates are RA , dec . It is located near the naked-eye class A4 star Zosma, as well as galaxies NGC 3608, NGC 3607, NGC 3659, NGC 3686, NGC 3684, NGC 3691, NGC 3681, and NGC 3655. Its dimensions are 2′.7 × 1′.9. The galaxy belongs to the NGC 3607 group some 70 million light-years distant, itself one of the many Leo II groups."
"NGC 3626 NGC 3626, also Caldwell 40, is a medium-tightness spiral galaxy and Caldwell object in the constellation Leo. It was discovered by William Herschel, on 14 March 1784. It shines at magnitude +10.6/+10.9. Its celestial coordinates are RA , dec . It is located near the naked-eye class A4 star Zosma, as well as galaxies NGC 3608, NGC 3607, NGC 3659, NGC 3686, NGC 3684, NGC 3691, NGC 3681, and NGC 3655. Its dimensions are 2′.7 × 1′.9. The galaxy belongs to the NGC 3607 group some 70 million light-years distant, itself one of the many Leo II groups."
"year as our galaxy, but they were much smaller and less massive, making it ""intensely star forming"". The light travel distance of the light that we observe from UDFy-38135539 (HUF.YD3) is more than 4 billion parsecs (13.1 billion light years), and it has a luminosity distance of 86.9 billion parsecs (about 283 billion light years). There are a number of different distance measures in cosmology, and both ""light travel distance"" and ""luminosity distance"" are different from the comoving distance or ""proper distance"" generally used in defining the size of the observable universe (comoving distance and proper distance are defined to"
"HD 3346 HD 3346, also known as V428 Andromedae, is a binary star system in the northern constellation of Andromeda. It is a dim star but visible to the naked eye under suitable viewing conditions, having an apparent visual magnitude of 5.14. The distance to HD 3346 can be determined from its annual parallax shift of . This yields a range of about 660 light year. At that distance the brightness of the system is diminished by an extinction of 0.16 magnitude due to interstellar dust. It is moving closer to the Earth with a heliocentric radial velocity of −33"
"fainter secondary, component B, is a magnitude 9.70 star located from the primary. It is an F-type main-sequence star with a class of F3 V that shows an unexplained long term variability. One of the components of this system displays a slight photometric variation with a period of 3.16 days. This may be caused by pulsation or an ellipsoidal variation. This system's X-ray emission hasn't been detected yet, with an upper limit of L < 29.79 erg/s. 26 Andromedae 26 Andromedae, abbreviated 26 And, is an astrometric binary star system in the constellation Andromeda. ""26 Andromedae"" is the Flamsteed designation."
"NGC 4026 NGC 4026 is a lenticular galaxy in the constellation Ursa Major. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 4026 is about 80,000 light years across. It was discovered by William Herschel on April 12, 1789. The galaxy hosts a supermassive black hole with estimated mass 10 (166-275 million) . NGC 4026 belongs to M109 Group, the largest subgroup of galaxies with the Ursa Major Cluster. In the vicinity of NGC 4026 lie some low surface brightness spiral galaxies, UGC 6917 (42 arcminutes from"
"HD 162826 HD 162826 (HR 6669, HIPP 87382) is a star in the constellation Hercules. It is about away from Earth. With an apparent magnitude of 6.46, the star can be found with binoculars or a low-power telescope by reference to nearby Vega in the constellation Lyra. It is very similar to the Sun; the Sun is a G2V star with a temperature of 5778 K and 4.6 billion years old while HD 162826 is a F8V star with a temperature of 6210 K, 4.5 billion years old, and is just 15% more massive than the Sun and 3% more"
"taxonomic system that ranges from ""nearly certainly"" to ""possibly"". As of 2018, no rotational lightcurve of has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown. 2013 FS28 "" orbits the Sun at a distance of 34.4–360 AU once every 2773 years (1,012,826 days; semi-major axis of 197 AU). Its orbit has an exceptionally high eccentricity of 0.83 and an inclination of 13° with respect to the ecliptic. It has a minimum orbital intersection distance with Neptune of 8.3 AU. The body's observation arc begins with its first official observation in March 2013, using the"
"HD 73526 HD 73526 is a G-type main-sequence star. It is about 310 light-years away in the constellation Vela. The star is cooler, more luminous, similar mass, and larger than our Sun. This star is 22% older than our Sun and with metallicity nearly doubled with the Sun, based on its abundance of iron. On June 13 2002, a 2.1 M planet HD 73526 b was announced orbiting HD 73526 in an orbit just a little smaller than that of Venus' orbit around the Sun. This planet receives insolation 3.65 times that of Earth or 1.89 times that of Venus."
"than an arcsecond. The components are an object of apparent visual magnitude 5.5, γ Andromedae B, and a type-A main sequence star with apparent visual magnitude 6.3, γ Andromedae C. They have an orbital period of about 64 years. Spectrograms taken from 1957 to 1959 revealed that γ Andromedae B was itself a spectroscopic binary, composed of two type-B main sequence stars orbiting each other with a period of 2.67 days. was the name of United States navy ship. Gamma Andromedae Gamma Andromedae (γ Andromedae, abbreviated Gamma And, γ And) is the third-brightest point of light in the constellation of"
"distance measurement you use. With a redshift of 5.34, light from this galaxy is estimated to have taken around 12.5 billion years to reach us. But since this galaxy is receding from Earth, the present comoving distance is estimated to be around 26 billion light-years. RD1 RD1 or 0140+326 RD1 is a distant galaxy, it once held the title of most distant galaxy known. RD1 was discovered in March 1998, and is at ""z"" = 5.34, and was the first object found to exceed redshift 5. It bested the previous recordholders, a pair of galaxies at z=4.92 lensed by the"
"is equivalent to a distance of approximately from Earth. 26 Arietis 26 Arietis (abbreviated 26 Ari) is a variable star in the northern constellation of Aries. ""26 Arietis"" is the Flamsteed designation; it also bears the variable star designation UU Arietis. The apparent visual magnitude of this star is 6.14, which, according to the Bortle Dark-Sky Scale, is within the naked eye visibility limit in dark rural skies. This is an A-type main sequence star with a stellar classification of A9 V. It is a Delta Scuti variable with a variability period of 0.0676 days and an amplitude of 0.010"
"NGC 4526 NGC 4526 (also listed as NGC 4560) is a lenticular galaxy located approximately 55 million light-years from the Solar System in the Virgo constellation and discovered on 13 April 1784 by William Herschel. The galaxy is seen nearly edge-on. The morphological classification is SAB(s)0°, which indicates a lenticular structure with a weak bar across the center and pure spiral arms without a ring. It belongs to the Virgo cluster and is one of the brightest known lenticular galaxies. In the galaxy's outer halo, globular cluster orbital velocities indicate abnormal poverty of dark matter: only 43±18% of the mass"
"Epsilon Normae Epsilon Normae, Latinised from ε Normae, is a blue-white hued triple star system in the southern constellation of Norma. It has an apparent visual magnitude of 4.47, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 6.15 mas as seen from Earth, the system is located around 530 light years distant from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.21 due to interstellar dust. The inner pair form a double-lined spectroscopic binary system with an orbital period of 3.26 days and"
"3 Andromedae 3 Andromedae, abbreviated 3 And, is a single star in the northern constellation of Andromeda. ""3 Andromedae"" is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.64. The distance to this star, as determined from an annual parallax shift of , is 181 light years. It is moving closer to the Earth with a heliocentric radial velocity of −35 km/s, and has a relatively large proper motion, traversing the celestial sphere at a rate of ·yr. This is an evolved giant star with a stellar classification of K0 IIIb, where"
"66 Andromedae 66 Andromedae is a binary star in the constellation Andromeda. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. It has a combined apparent magnitude of 6.16, which is just below the nominal brightness limit of stars that are visible to the naked eye under good seeing conditions. An annual parallax shift of 17.69 mas provides a distance estimate of around 184 light years. This is a double-lined spectroscopic binary system with an orbital period of 11 days and an eccentricity of 0.19. The two components are similar stars with a"
"""LAL 25372"". High proper motion of this star and its large parallax were known at least from 1911, when Frank Schlesinger published a paper where he announced its parallax and mentioned its proper motion value of 2.3 arcsec. In 1919, German astronomer Max Wolf included GJ 526 in his catalogue of high proper motion stars, giving it the identifier 498. GJ 526 is a flare star, which means it undergoes sporadic increases in brightness of up to 1–6 magnitudes. It is a main sequence red dwarf with a stellar classification of M1.5 V. GJ 526 is smaller than the Sun,"
"Lambda Librae λ Librae (Latinised as Lambda Librae) is the Bayer designation for a binary star system in the zodiac constellation of Libra. It can be faintly seen with the naked eye on a dark night, having an apparent visual magnitude of 5.03. With an annual parallax shift of 10.54 mas, it is located roughly 310 light years from the Sun. At that distance, the visual magnitude of this system is diminished by an extinction factor of 0.22 due to interstellar dust. This is a single-lined spectroscopic binary star system with an orbital period of 14.48 days and an eccentricity"
"they appeared 13 billion years ago, when the universe was less than a billion years old. The fact that more distant objects appear to be younger, due to the finite speed of light, allows astronomers to infer the evolution of stars, of galaxies, and of the universe itself. Astronomical distances are sometimes expressed in light-years, especially in popular science publications and media. A light-year is the distance light travels in one year, around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. Proxima Centauri,"
"more distant background. These shifts are angles in an isosceles triangle, with 2 AU (the distance between the extreme positions of Earth's orbit around the Sun) making the base leg of the triangle and the distance to the star being the long equal length legs. The amount of shift is quite small, measuring 1 arcsecond for an object at 1 parsec's distance (3.26 light-years) of the nearest stars, and thereafter decreasing in angular amount as the distance increases. Astronomers usually express distances in units of parsecs (parallax arcseconds); light-years are used in popular media. Because parallax becomes smaller for a"