Share to: share facebook share twitter share wa share telegram print page

NGC 1818

NGC 1818
A Hubble Space Telescope (HST) image of NGC 1818
Observation data (J2000 epoch)
ConstellationDorado
Right ascension05h 04m 13.300s[1]
Declination−66° 26′ 05.47″[1]
Distance~164 kly (50 kpc)[2]
Apparent magnitude (V)9.7 (B band)[3]
Physical characteristics
Absolute magnitude−8.8[4]
Mass13,500+5,600
−3,700
 M
Estimated age30[5] or 40 Myr[6]
Notable featuresRare young globular
See also: Globular cluster, List of globular clusters

NGC 1818 is a young globular cluster in the north-west part of the Large Magellanic Cloud, about 3.2 kpc from the center.[7] It was discovered by Scottish astronomer James Dunlop in 1826,[8] and has since been well studied.[4]

The cluster has an estimated core radius of 2.67 pc and a 90% light radius of 13.83 pc,[1] with a combined mass of around 13,500 times the mass of the Sun.[5] Age estimates for the cluster range from 25[7] to 40[6] million years. Given this, most stars with a mass equal to the Sun or less are still on the pre-main-sequence. The average stellar metallicity – what astronomers term the abundance of elements with higher atomic number than helium – is −0.4, or about 10−0.4 ≈ 40% of the abundance in the Sun.[4]

There appear to be two distinct stellar populations in the cluster with the more blue (hotter) stars showing slower rotation rates than the redder (cooler) stars.[6] The frequency of binary star systems in the cluster increases with distance from the core, which is the opposite of the normal trend for globular clusters. This may be explained by interactions with other stars in the denser core disrupting binary systems, before mass segregation of the cluster has begun to take effect.[5] The cluster contains few if any blue stragglers, which are the result of stellar mergers.[7]

References

  1. ^ a b c Werchan, Felicia; Zaritsky, Dennis (August 2011). "The Star Clusters of the Large Magellanic Cloud: Structural Parameters". The Astronomical Journal. 142 (2): 10. arXiv:1105.1769. Bibcode:2011AJ....142...48W. doi:10.1088/0004-6256/142/2/48. S2CID 118331608. 48.
  2. ^ Elson, Rebecca; Sword, Richard; NASA. "Hot white dwarf shines in young star cluster NGC 1818". Hubblesite. Retrieved 2020-08-26.
  3. ^ SIMBAD (January 8, 2007), Results for NGC 1818, SIMBAD, Centre de Données Astronomiques de Strasbourg
  4. ^ a b c Liu, Q.; de Grijs, R.; Deng, L. C.; Hu, Y.; Baraffe, I.; Beaulieu, S. F. (July 2009). "The initial mass function of the rich young cluster NGC 1818 in the Large Magellanic Cloud". Monthly Notices of the Royal Astronomical Society. 396 (3): 1665–1674. arXiv:0903.4787. Bibcode:2009MNRAS.396.1665L. doi:10.1111/j.1365-2966.2009.14838.x. S2CID 14155137.
  5. ^ a b c Geller, Aaron M.; et al. (May 2015). "Different Dynamical Ages for the Two Young and Coeval LMC Star Clusters, NGC 1805 and NGC 1818, Imprinted on Their Binary Populations". The Astrophysical Journal. 805 (1): 11. arXiv:1503.05198. Bibcode:2015ApJ...805...11G. doi:10.1088/0004-637X/805/1/11. S2CID 55039592. 11.
  6. ^ a b c Marino, A. F.; et al. (September 2018). "Different Stellar Rotations in the Two Main Sequences of the Young Globular Cluster NGC 1818: The First Direct Spectroscopic Evidence". The Astronomical Journal. 156 (3): 10. arXiv:1807.04493. Bibcode:2018AJ....156..116M. doi:10.3847/1538-3881/aad3cd. S2CID 119366707. 116.
  7. ^ a b c Johnson, R. A.; et al. (2001). "Young star clusters in the Large Magellanic Cloud: NGC 1805 and 1818". Monthly Notices of the Royal Astronomical Society. 324 (2): 367. arXiv:astro-ph/0012389. Bibcode:2001MNRAS.324..367J. doi:10.1046/j.1365-8711.2001.04291.x. S2CID 15010067.
  8. ^ Seligman, Courtney. "NGC 1818". Celestial Atlas. Retrieved 7 December 2018.


Read other articles:

Planned ParenthoodSingkatanPPFAPendahuluAmerican Birth Control LeagueTanggal pendirian16 Oktober 1916; 107 tahun lalu (1916-10-16)TujuanKesehatan reproduksiKantor pusat Manhattan, New York City, New York, U.S. Washington, D.C., U.S. Wilayah layanan Amerika Serikat, dan seluruh duna melalui Planned Parenthood Global dan IPPF[1]Jumlah anggota 600+  lokasi klinik[2] ≈58  afiliasi medis atau afiliasi terkait ≈101  afiliasi non-medis [3] Acting Presiden…

UK Singles Chart number ones UK Singles Chart 1950s 1960s 1970s 1980s 1990s 2000s 2010s 2020s Other charts Melody Maker – 1956–1969 Melody Maker – 1970s Melody Maker – 1980s NME – 1960s NME – 1970s NME – 1980s Record Mirror (1955–1962) Miscellaneous charts 1952–1969 Miscellaneous charts 1969–1988 Related Official Charts Company Christmas number one NME (or New Musical Express) was a British weekly pop music newspaper. Record charts in the United Kingdom began life on 14 Novem…

Pemandangan Heiligendamm pada bulan Juni 2007. Heiligendamm (dilafalkan: ˈhaɪlɪɡəndam) adalah desa tetirah tepi Laut Baltik di Jerman Utara. Dalam bulan Juni 2007, kota ini menjadi pusat perhatian dunia karena menjadi tempat berlangsungnya Pertemuan Puncak G8 ke-33. Secara administratif, desa ini berada di kota Bad Doberan, Distrik Bad Doberan, negara bagian Mecklenburg-Vorpommern. Sejarah Sejarah Heiligendamm sebagai sebuah tempat tetirah dimulai tahun 1793. Penguasa daerah itu, bangsawan …

Lisbon DistrictDistrictCountryPortugalRegionLisbon(partly Alentejo Region)Historical provinceEstremadura Province(partly Ribatejo Province)No. of municipalities16No. of parishes226CapitalLisbonLuas • Total2,800 km2 (1,081 sq mi)Populasi • Total2.135.992 • Kepadatan0,76/km2 (2,0/sq mi)No. of parliamentary representatives47 Distrik Lisboa (pengucapan bahasa Portugis: [liʒˈβoɐ], Portugis: Distrito de Lisboacode: pt is deprecated ) mer…

Bulgarian football club Football clubOFC NesebarFull nameMunicipal Football Club NesebarNickname(s)The DolphinsFounded1946; 78 years ago (1946)GroundStadion Nesebar, NesebarCapacity10,000OwnerNesebar MunicipalityChairmanGeorgi MarinovHead coachVasil BanovLeagueThird League2022–23Third League, 1st Home colours Away colours Third colours Nesebar (Bulgarian: Несебър) is a Bulgarian municipal (Bulgarian: общински, pronounced obshtinski) association football club ba…

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Oakland School for the Arts – news · newspapers · books · scholar · JSTOR (May 2007) (Learn how and when to remove this template message) Public charter school in Oakland, California, United StatesOakland School for the ArtsOakland School for the ArtsAddress530 18…

County in Missouri, United States Not to be confused with Sullivan, Missouri. County in MissouriSullivan CountyCountySullivan County Courthouse in MilanLocation within the U.S. state of MissouriMissouri's location within the U.S.Coordinates: 40°13′N 93°07′W / 40.21°N 93.11°W / 40.21; -93.11Country United StatesState MissouriFounded1843 (created)1845 (organized)Named forJohn SullivanSeatMilanLargest cityMilanArea • Total652 sq mi (1,…

Politeknik Perkapalan Negeri SurabayaShipbuilding Institute of Polytechnic SurabayaJenisPerguruan Tinggi Negeri, PoliteknikDidirikan01 April 1987 (berdiri), 06 Juni 1991 (SK pendirian)DirekturIr. Eko Julianto M.ScAlamatJl. Teknik Kimia, Kampus ITS Sukolilo, Surabaya, Jawa Timur, IndonesiaKampusKampus ITS SukoliloSitus webhttps://ppns.ac.id/ Politeknik Perkapalan Negeri Surabaya atau Shipbuilding Institute of Polytechnic Surabaya yang disingkat PPNS-SHIPS adalah satu satunya politeknik negeri di …

Kongres Amerika Serikat ke-29United States Capitol (1846)Periode4 Maret 1845 – 4 Maret 1847Anggota58 senator228 anggota dewan2 delegasi tanpa suaraMayoritas SenatDemokratPresiden SenatGeorge M. DallasMayoritas DPRDemokratKetua DPRJohn W. DavisPres. Senat Pro TemporeWillie P. MangumAmbrose H. SevierDavid R. AtchisonSesike-1: 1 Desember 1845 – 10 Agustus 1846ke-2: 7 Desember 1846 – 3 Maret 1847ke-28 ←→ ke-30 Kongres Amerika Serikat Kedua Puluh Sembilan adalah sidang cabang…

Israeli Supreme Court justice Ayala ProcacciaAyala ProcacciaJustice of the Supreme Court of IsraelIn office2001–2011 Personal detailsBorn1941 (age 82–83)Ashdot Ya'akov, IsraelEducationHebrew University of Jerusalem (LLB, MA)University of Pennsylvania (SJD) Ayala Procaccia (Hebrew: אילה פרוקצ'יה, born 1941) is a retired Israeli Justice of the Supreme Court of Israel. Before being elected to the Supreme Court in 2001, she served as a judge in the Jerusalem Magistrates’ Co…

Femke GerritseInformationsNaissance 14 mai 2001 (22 ans)Bois-le-Duc ou RosmalenNationalité néerlandaiseÉquipe actuelle SD Worx-ProtimeÉquipes UCI 2021-2023Parkhotel Valkenburg2024-SD Worx-Protimemodifier - modifier le code - modifier Wikidata Femke Gerritse (née le 14 mai 2001 à Bois-le-Duc) est une coureuse cycliste néerlandaise. Biographie Cette section est vide, insuffisamment détaillée ou incomplète. Votre aide est la bienvenue ! Comment faire ? Elle participe au pre…

Questa voce sull'argomento calciatori italiani è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Alessandro Banfi Nazionalità  Italia Calcio Ruolo Terzino Carriera Squadre di club1 1930-1932 Monza11 (0)1932-1933 Comense17 (0)1933-1938 Monza123 (6)1938-1943 Como119 (1)1945-1946 Casatese? (?) 1 I due numeri indicano le presenze e le reti segnate, per le sole partite di campionato…

Thor adalah sebuah rudal balistik operasional yang pertama digunakan oleh Angkatan Udara AS (USAF). Dinamakan setelah dewa guntur Norse, ditempatkan di Inggris antara 1959 dan September 1963 sebagai rudal balistik (IRBM) kisaran menengah dengan hulu ledak termonuklir. Thor adalah dengan diameter 65 kaki (20 m) tinggi dan 8 kaki (2,4 m). Sebuah keluarga besar ruang peluncuran kendaraan-Thor dan roket Delta berasal dari desain Thor. Sebuah versi modifikasi masih digunakan sebagai tahap pertama dar…

この記事は検証可能な参考文献や出典が全く示されていないか、不十分です。出典を追加して記事の信頼性向上にご協力ください。(このテンプレートの使い方)出典検索?: コルク – ニュース · 書籍 · スカラー · CiNii · J-STAGE · NDL · dlib.jp · ジャパンサーチ · TWL(2017年4月) コルクを打ち抜いて作った瓶の栓 コルク(木栓、蘭&…

Le amanti di Monsieur RipoisAndré (Gérard Philipe) e Patrizia (Natasha Parry)Titolo originaleMonsieur Ripois Lingua originalefrancese Paese di produzioneFrancia, Regno Unito Anno1954 Durata100 min Dati tecniciB/Nrapporto: 1,37:1 Generedrammatico, commedia RegiaRené Clément Soggettoromanzo Il signor Ripois e il suo destino di Louis Hémon SceneggiaturaRené Clément, Hugh Mills ProduttorePaul Graetz Casa di produzioneTranscontinental Films e Transcontinental Film Productions (London) …

この項目には、一部のコンピュータや閲覧ソフトで表示できない文字が含まれています(詳細)。 数字の大字(だいじ)は、漢数字の一種。通常用いる単純な字形の漢数字(小字)の代わりに同じ音の別の漢字を用いるものである。 概要 壱万円日本銀行券(「壱」が大字) 弐千円日本銀行券(「弐」が大字) 漢数字には「一」「二」「三」と続く小字と、「壱」「弐」…

Italian actor (born 1972) Valerio MastandreaMastandrea in 2010Born (1972-02-14) 14 February 1972 (age 52)Rome, ItalyOccupations Actor director writer producer Valerio Mastandrea (born 14 February 1972) is an Italian film, stage and television actor. Life and career He was born in Rome. While being a student of philosophy, in the early 1990s Mastandrea enjoyed some success thanks to the semi-regular participation in the Canale 5 late night talk show Maurizio Costanzo Show.[1] After s…

Ricky Bell Bell nei playoff 1979 Nazionalità  Stati Uniti Football americano Ruolo Running back Termine carriera 1982 CarrieraGiovanili  USC TrojansSquadre di club 1977-1981 Tampa Bay Buccaneers1982 San Diego Chargers Statistiche Partite 64 Yard corse 3.063 Touchdown su corsa 16   Modifica dati su Wikidata · Manuale Ricky Lynn Bell (Houston, 8 aprile 1955 – Los Angeles, 28 novembre 1984) è stato un giocatore di football americano, di nazionalità statunitense, …

这是马来族人名,“尤索夫”是父名,不是姓氏,提及此人时应以其自身的名“法迪拉”为主。 尊敬的拿督斯里哈芝法迪拉·尤索夫Fadillah bin Haji YusofSSAP DGSM PGBK 国会议员 副首相 第14任马来西亚副首相现任就任日期2022年12月3日与阿末扎希同时在任君主最高元首苏丹阿都拉陛下最高元首苏丹依布拉欣·依斯迈陛下首相安华·依布拉欣前任依斯迈沙比里 马来西亚能源转型与公共…

The Croatian Volleyball Federation (Croatian: Hrvatski odbojkaški savez, HOS) is the governing body of volleyball in Croatia. It is based in Zagreb. It organizes the following volleyball leagues: 1A Men's Volleyball League 1B Men's Volleyball League 1A Women's Volleyball League 1B Women's Volleyball League It also organizes the Croatian national volleyball team and the Croatian national women's volleyball team. The HOS was formed in 1946. It is a member of the Fédération Internationale de Vol…

Kembali kehalaman sebelumnya