|
Solar Sibling
A solar sibling is a star that formed in the same star cluster as the Sun. Stars that have been proposed as candidate solar siblings include HD 162826, HD 175740, and HD 186302. There is as yet no confirmed solar sibling and studies disagree on the most likely candidates; for example, a 2016 study suggested that previous candidates, including HD 162826 and HD 175740, are unlikely to be solar siblings. A study using Gaia DR2 data published in 2020 found that HD 186302 is unlikely to be a solar sibling, while identifying a new candidate, "Solar Sibling 1", designated 2MASS J19354742+4803549. This star is also known as Kepler-1974 or KOI-7368, and was found in 2022 to be a member of a stellar association that is 40 million years old, much younger than the Sun, so it cannot be a solar sibling. A 2019 study of the comet C/2018 V1 (Machholz–Fujikawa–Iwamoto) found that it may be an interstellar object, and identified two stars it may have originated from (Gaia DR2 192714351495 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Formation
Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations. First stars Star formation is divided into three groups called "Populations". Population III stars formed from primordial hydrogen after the Big Bang. These stars are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Cluster
A star cluster is a group of stars held together by self-gravitation. Two main types of star clusters can be distinguished: globular clusters, tight groups of ten thousand to millions of old stars which are gravitationally bound; and open clusters, less tight groups of stars, generally containing fewer than a few hundred members. As they move through the galaxy, over time, open clusters become disrupted by the gravitational influence of giant molecular clouds, so that the clusters we observe are often young. Even though they are no longer gravitationally bound, they will continue to move in broadly the same direction through space and are then known as stellar associations, sometimes referred to as ''moving groups''. Globular clusters, with more members and more mass, remain intact for far longer and the globular clusters we observe are usually billions of years old. Star clusters visible to the naked eye include the Pleiades and Hyades (star cluster), Hyades open clusters, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 162826
HD 162826 (HR 6669, HIP 87382) is a star in the constellation Hercules. It is about away from Earth. With an apparent magnitude of 6.55, the star can be found with binoculars or a low-power telescope by reference to nearby Vega in the constellation Lyra. The star is considered to be a stellar sibling of the Sun and is the first such sibling to be discovered. Solar siblings are those stars that formed from the same gas cloud and in the same star cluster; the term was introduced in 2009. No planets have been detected orbiting HD 162826, but due to its metallicity, it is likely to harbor terrestrial planets; the star's spectra had been under observation previously. In November 2018, a second potential solar twin was announced, HD 186302, an 8th magnitude star in the Pavo constellation, King, Bob P. (2018-11-24). Did Astronomers Just Find The Sun’s Sister? Astro Bob, Duluth News Tribune, 24 November 2018. Originally retrieved from http://astrobob.are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 175740
HD 175740 is a single star in the northern constellation of Lyra. This object has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.46. It is located at a distance of approximately 266 light years from the Sun based on parallax, and has an absolute magnitude of 0.89. The star is drifting closer with a radial velocity of −9.5 km/s, and is predicted to come as close as in around 8 million years. This is an aging giant star with a stellar classification of K0III, having evolved off the main sequence after the supply of hydrogen at its core was exhausted. It is an estimated 4.78 billion years old with 1.39 times the mass of the Sun, although Bailer-Jones et al. (2018) give a higher estimate of 2.8 times the Sun's mass. The elemental composition of this star has made it the first giant to be a candidate solar sibling, suggesting it may have been born in the same star cluster as the Sun. It has expanded to ten times ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 186302
HD 186302 (also designated HIP 97507) is a star in the constellation of Pavo. It is away from Earth, with an apparent magnitude of 8.76. It was identified in November 2018 as a potential solar sibling to the Sun. Similar in spectrum and size, it was suspected to have formed in the same stellar nursery as the Sun 4.6 billion years ago. However, a common origin with the Sun was found to be unlikely in a 2019 paper, as HD 186302's galactic orbit is very different from the Sun's. See also * HD 162826; the first star identified as a solar sibling in February 2014, in Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the Gr .... References {{DEFAULTSORT:HD 186302 Solar twins G-type main-sequence stars 186302 097507 J19490644-7011167 Pavo (constellation) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaia DR2
The ''Gaia'' catalogues are star catalogues created using the results obtained by ''Gaia (spacecraft), Gaia'' space telescope. The catalogues are released in stages that will contain increasing amounts of information; the early releases also miss some stars, especially fainter stars located in dense star fields. Data from every data release can be accessed at the ''Gaia'' archive. Initial Gaia Source List The Initial Gaia Source List (IGSL) is a star catalogue of 1.2 billion objects created in support of the ''Gaia'' mission. The mission should have delivered a catalogue based entirely on its own data. For the first catalogue, Gaia DR1, a way was needed to be able to assign the observations to an object and to compare them with the objects from other star catalogues. For this purpose, a separate catalog of objects from several other catalogues was compiled, which roughly represents the state of knowledge of astronomy at the beginning of the Gaia mission. Attitude Star Catalog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Association
A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more visible stars. An association is primarily identified by commonalities in its member stars' movement vectors, ages, and chemical compositions. These shared features indicate that the members share a common origin. Nevertheless, they have become gravitationally unbound, unlike star clusters, and the member stars will drift apart over millions of years, becoming a moving group as they scatter throughout their neighborhood within the galaxy. Stellar associations were discovered by Victor Ambartsumian in 1947. The conventional name for an association uses the names or abbreviations of the constellation (or constellations) in which they are located; the association type, and, sometimes, a numerical identifier. Types Victor Ambartsumian first categorized stellar associations into two groups, OB and T, based on the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C/2018 V1 (Machholz–Fujikawa–Iwamoto)
C/2018 V1 (Machholz–Fujikawa–Iwamoto) is a comet that follows a slightly hyperbolic trajectory. It was visually discovered on 7 November 2018 by Donald Machholz using an 18.5-inch reflecting telescope, and was independently co-discovered by Shigehisa Fujikawa and Masayuki Iwamoto respectively. It reached perihelion on 3 December 2018. Overview It was estimated to be between 8 and 10th magnitude from mid-November to mid-December 2018, visible in a small telescope. It was discovered by three amateur astronomers: by an observer in Colfax, California, USA and by two observers in Japan. The observations by three astronomers result in the name for the comet, Machholz-Fujikawa-Iwamoto. The current orbit determination of this comet is based on 750 observations with a 37-day observation arc. Comet C/2018 V1 has a significant probability (72.6%) of having an extrasolar provenance although an origin in the Oort Cloud The Oort cloud (pronounced or ), sometimes called the Öpi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interstellar Object
An interstellar object is an astronomical object in interstellar space that is not gravitationally bound to a star. Applicable objects include asteroids, comets, and rogue planets, but not a star or stellar remnant. This term can also be applied to an object that is on an interstellar trajectory but is temporarily passing close to a star, such as certain asteroids and comets (that is, exoasteroids and exocomets). In the latter case, the object may be called an interstellar interloper. The first interstellar objects discovered were rogue planets, planets ejected from their original stellar system (e.g., OTS 44 or Cha 110913−773444), though they are difficult to distinguish from sub-brown dwarfs, planet-mass objects that formed in interstellar space as stars do. The first interstellar object which was discovered traveling through the Solar System was ʻOumuamua, 1I/ʻOumuamua in 2017. The second was 2I/Borisov in 2019. They both possess significant Hyperbolic trajectory#Semi-m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oort Cloud
The Oort cloud (pronounced or ), sometimes called the Öpik–Oort cloud, is scientific theory, theorized to be a cloud of billions of Volatile (astrogeology), icy planetesimals surrounding the Sun at distances ranging from 2,000 to 200,000 Astronomical unit, AU (0.03 to 3.2 light-years). The cloud was proposed in 1950 by the Dutch astronomer Jan Oort, in whose honor the idea was named. Oort proposed that the bodies in this cloud replenish and keep constant the number of Comet, long-period comets entering the inner Solar System—where they are eventually consumed and destroyed during close approaches to the Sun. The cloud is thought to encompass two regions: a circumstellar disc, disc-shaped inner Oort cloud aligned with the Ecliptic, solar ecliptic (also called its Hills cloud) and a circumstellar envelope, spherical outer Oort cloud enclosing the entire Solar System. Both regions lie well beyond the heliosphere and are in Outer space#Interstellar space, interstellar space. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astrophysical Journal
''The Astrophysical Journal'' (''ApJ'') is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015. Since 1953, ''The Astrophysical Journal Supplement Series'' (''ApJS'') has been published in conjunction with ''The Astrophysical Journal'', with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume. ''The Astrophysical Journal Letters'' (''ApJL''), established in 1967 by Subrahmanyan Chandrasekhar as Part 2 of ''The Astrophysical Journal'', is now a separate journal focusing on the rapid publication of high-impact astronomical research. The three journals were published by the University of Chicago Press for the American Astronomical Society until, in January 2009, publication was transferred to IOP Publis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields. It publishes original research in two formats: papers (of any length) and letters (limited to five pages). MNRAS publishes more articles per year than any other astronomy journal. The learned society journal has been in continuous existence since 1827 and became online only in 2020. It operates as a partnership between the Royal Astronomical Society (RAS), who select and peer-review the contents, and Oxford University Press (OUP), who publish and market the journal. Despite its name, MNRAS is no longer monthly, nor does it carry the notices of the RAS. In 2024 MNRAS became a purely gold open access journal. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
