PG 1159 star

A PG 1159 star, often also called a pre-degenerate,[1] is a star with a hydrogen-deficient atmosphere that is in transition between being the central star of a planetary nebula and being a hot white dwarf. These stars are hot, with surface temperatures between 75,000 K and 200,000 K,[2] and are characterized by atmospheres with little hydrogen and absorption lines for helium, carbon and oxygen. Their surface gravity is typically between 104 and 106 meters per second squared. Some PG 1159 stars are still fusing helium.[3], § 2.1.1, 2.1.2, Table 2. The PG 1159 stars are named after their prototype, PG 1159-035. This star, found in the Palomar-Green survey of ultraviolet-excess stellar objects,[4] was the first PG 1159 star discovered.

It is thought that the atmospheric composition of PG 1159 stars is odd because, after they have left the asymptotic giant branch, they have reignited helium fusion. As a result, a PG 1159 star's atmosphere is a mixture of material which was between the hydrogen- and helium-burning shells of its AGB star progenitor.[3], §1. They are believed to eventually lose mass, cool, and become DO white dwarfs.[2]; [5], §4.

Some PG 1159 stars have varying luminosities. These stars vary slightly (5–10%) in brightness due to non-radial gravity wave pulsations within themselves. They vibrate in a number of modes simultaneously, with typical periods between 300 and 3,000 seconds.[6][7], Table 1. The first known star of this type is also PG 1159-035, which was found to be variable in 1979,[8] and was given the variable star designation GW Vir in 1985.[9] These stars are called GW Vir stars, after their prototype, or the class may be split into DOV and PNNV stars.[7], § 1.1;[10]

See also

References

  1. ^ Jaschek & Jaschek: CARBON C
  2. ^ a b Huegelmeyer, S. D.; Dreizler, S.; Werner, K.; Krzesinski, J.; Nitta, A.; Kleinman, S. J. (2006). "Observational constraints on the evolutionary connection between PG 1159 stars and DO white dwarfs". arXiv:astro-ph/0610746.
  3. ^ a b Werner, Klaus; Herwig, Falk (2006). "The Elemental Abundances in Bare Planetary Nebula Central Stars and the Shell Burning in AGB Stars". Publications of the Astronomical Society of the Pacific. 118 (840): 183. arXiv:astro-ph/0512320. Bibcode:2006PASP..118..183W. doi:10.1086/500443.
  4. ^ Green, R. F.; Schmidt, M.; Liebert, J. (1986). "The Palomar-Green Catalog of Ultraviolet-Excess Stellar Objects". The Astrophysical Journal Supplement Series. 61: 305. Bibcode:1986ApJS...61..305G. doi:10.1086/191115.
  5. ^ Koesterke, Lars; Werner, Klaus (1998). "Determination of Mass-Loss Rates of PG 1159 Stars from Far-Ultraviolet Spectroscopy". The Astrophysical Journal. 500 (1): L55–L59. Bibcode:1998ApJ...500L..55K. doi:10.1086/311383.
  6. ^ Winget, D. E. (1998). "Asteroseismology of white dwarf stars". Journal of Physics: Condensed Matter. 10 (49): 11247–11261. Bibcode:1998JPCM...1011247W. doi:10.1088/0953-8984/10/49/014.
  7. ^ a b Quirion, P. -O.; Fontaine, G.; Brassard, P. (2007). "Mapping the Instability Domains of GW vir Stars in the Effective Temperature-Surface Gravity Diagram". The Astrophysical Journal Supplement Series. 171 (1): 219. Bibcode:2007ApJS..171..219Q. doi:10.1086/513870.
  8. ^ McGraw, J. T.; Starrfield, S. G.; Liebert, J.; Green, R. (1979). "PG 1159-035: A New, Hot, Non-Da Pulsating Degenerate". IAU Colloq. 53: White Dwarfs and Variable Degenerate Stars: 377. Bibcode:1979wdvd.coll..377M.
  9. ^ Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars. 2681: 1. Bibcode:1985IBVS.2681....1K.
  10. ^ Nagel, T.; Werner, K. (2004). "Detection of non-radial g-mode pulsations in the newly discovered PG 1159 star HE 1429-1209". Astronomy and Astrophysics. 426. arXiv:astro-ph/0409243. Bibcode:2004A&A...426L..45N. doi:10.1051/0004-6361:200400079.

Read other articles:

Strada statale 267 del Cilento

Strada statale 267del CilentoLocalizzazioneStato Italia Regioni Campania Province Salerno DatiClassificazioneStrada statale InizioBivio Mattine FineSS 18 presso Vallo Scalo Lunghezza57,705[1] km Data apertura1960 Provvedimento di istituzioneD.M. 16/11/1959 - G.U. 41 del 18/02/1960[2] GestoreTratte ANAS: nessuna (dal 2001 la gestione è passata alla Regione Campania che ha ulteriormente devoluto le competenze alla Provincia di Salerno) PercorsoPrincipali intersez...

 

 

Iris (seri televisi)

IrisPoster promosi untuk IrisGenreLagaRomansaThrillerDitulis olehKim Hyun-junJo Gyu-wonKim Jae-unSutradaraKim Kyu-taeYang Yun-hoPemeranLee Byung-hunKim Tae-heeJung Joon-hoKim Seung-wooKim So-yeonChoi Seung-hyunPenata musikYi Dong-junChoe Seong-gownNegara asalKorea SelatanBahasa asliKoreaInggrisJepangHungariaMandarinJmlh. musim1Jmlh. episode20ProduksiLokasi produksiSeoul, Korea SelatanAkita, JepangShanghai, TiongkokBudapest, HungariaDurasi60 menit Rabu dan Kamis pukul 21:55 (WSK)Rumah p...

 

 

Delma Byron

American dancer and actress (1913–2006) 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: Delma Byron – news · newspapers · books · scholar · JSTOR (May 2020) (Learn how and when to remove this template message) Delma ByronDelma ByronBornSara Delma Bynum(1913-07-31)July 31, 1913Weakley County, TennesseeDiedM...

Castroisme

Artikel ini merupakan bagian dariseri mengenai:Komunisme KonsepFilosofi Marxis Ekonomi Marxian Materialisme historis Nilai lebih Mode produksi Perjuangan kelas Masyarakat Tanpa Kelas Internasionalisme proletariat Revolusi Dunia Aspek Negara komunis Partai komunis Revolusi komunis Simbolisme komunis Komunisme dan agama Sejarah komunisme Jenis Marxisme Leninisme Trotskyisme Maoisme Luxemburgisme Titoisme Stalinisme Castroisme Guevarisme Hoxhaisme Juche Komunisme sayap kiri Dewan komunisme Komun...

 

 

Jewish Autonomous Oblast

Federal subject of the Russian Federation in the Russian Far East Autonomous oblast in Far Eastern, RussiaJewish Autonomous OblastAutonomous oblastЕврейская автономная областьOther transcription(s) • Yiddishייִדישע אװטאָנאָמע געגנט‎‎A wintery Tunguska River near Nikolaevka village. FlagCoat of armsCoordinates: 48°36′N 132°12′E / 48.600°N 132.200°E / 48.600; 132.200CountryRussiaFederal dist...

 

 

Bertha Townsend

Questa voce sull'argomento tennisti statunitensi è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Bertha Townsend Nazionalità  Stati Uniti Tennis Carriera Singolare1 Vittorie/sconfitte 2 Titoli vinti Miglior ranking Risultati nei tornei del Grande Slam  Australian Open -  Roland Garros -  Wimbledon -  US Open V (1888, 1889) Doppio1 Vittorie/sconfitte Titoli vinti 1 Miglior ranking Risultati nei tornei del Grande Slam  Aus...

Sentinelle (Marvel Comics)

SentinelleLa Sentinella contro la Bestia e l'Uomo Ghiaccio, disegni di Neal Adams UniversoUniverso Marvel Lingua orig.Inglese AutoriStan Lee Jack Kirby Werner Roth EditoreMarvel Comics 1ª app.novembre 1965 1ª app. inX-Men (vol. 1[1]) n. 14 Editore it.Editoriale Corno 1ª app. it.1973 1ª app. it. inCapitan America n. 16 Voci orig.David Fox (Insuperabili X-Men) Dan Hennessey (X-Men: Children of the Atom, Marvel vs. Capcom 2: New Age of Heroes) Scott MacDonald (X...

 

 

Rachel Weisz

Rachel Weisz nel 2019 Oscar alla miglior attrice non protagonista 2006 Rachel Hannah Weisz (in inglese /ˈreɪtʃəl ˈvaɪs/; Londra, 7 marzo 1970) è un'attrice e produttrice cinematografica britannica naturalizzata statunitense[1]. Acquisisce notorietà grazie al ruolo di Evelyn Carnahan nel film d'avventura La mummia (1999) e La mummia - Il ritorno (2001), Weisz ha recitato anche ne Il nemico alle porte (2001), About a Boy - Un ragazzo (2002), Constantine (2005), The Fountain - L'...

 

 

Fatima Payman

Australian politician SenatorFatima PaymanPayman in 2022Senator for Western AustraliaIncumbentAssumed office 1 July 2022Preceded byBen Small Personal detailsBornc. 1995Kabul, AfghanistanPolitical partyLabor Fatima Payman (Persian: فاطمه پیمان; born c. 1995) is an Afghan-born Australian politician[1] who has served as senator for Western Australia since 2022.[2] Representing the Labor Party, she became the Australian Parliament's first hijab-wearing Mu...

哈萨克斯坦总统

此条目序言章节没有充分总结全文内容要点。 (2019年3月21日)请考虑扩充序言，清晰概述条目所有重點。请在条目的讨论页讨论此问题。 哈萨克斯坦總統哈薩克總統旗現任Қасым-Жомарт Кемелұлы Тоқаев卡瑟姆若马尔特·托卡耶夫自2019年3月20日在任任期7年首任努尔苏丹·纳扎尔巴耶夫设立1990年4月24日（哈薩克蘇維埃社會主義共和國總統） 哈萨克斯坦 哈萨克斯坦政府...

 

 

Ron Klein

American politician and lawyer (born 1957) This article is about the former Florida politician. For the White House Chief of Staff, see Ron Klain. For others with similar names, see Ron Klein (disambiguation). Ron KleinMember of the U.S. House of Representativesfrom Florida's 22nd districtIn officeJanuary 3, 2007 – January 3, 2011Preceded byClay ShawSucceeded byAllen WestMinority Leader of the Florida SenateIn office2002–2004Preceded byTom RossinSucceeded byLes Miller...

 

 

Tito Landrum

American baseball player Baseball player Tito LandrumTito Landrum at 25th Anniversary of Orioles' 1983 World Series ChampionshipOutfielderBorn: (1954-10-25) October 25, 1954 (age 69)Joplin, Missouri, U.S.Batted: RightThrew: RightMLB debutJuly 24, 1980, for the St. Louis CardinalsLast MLB appearanceMay 9, 1988, for the Baltimore OriolesMLB statisticsBatting average.249Home runs13Runs batted in111 Teams St. Louis Cardinals (1980–1983) Baltimore Orioles (1983...

Lawn bowls at the 2018 Commonwealth Games

Lawn bowls at the 2018 Commonwealth GamesVenueBroadbeach Bowls ClubDates5 – 13 April 2018Competitors240 from 28 nations← 20142022 → Lawn bowls at the2018 Commonwealth GamesSinglesmenwomenPairsmenwomenTriplesmenwomenFoursmenwomenPara-sport pairsmixedPara-sport triplesopenvte Lawn bowls at the 2018 Commonwealth Games was held at the Broadbeach Bowls Club in the Gold Coast, Australia from April 5 to 13.[1][2] Lawn bowls is one of ten c...

 

 

箫

  提示：此条目页的主题不是萧。 簫琴簫與洞簫木管樂器樂器別名豎吹、豎篴、通洞分類管樂器相關樂器 尺八 东汉时期的陶制箫奏者人像，出土於彭山江口汉崖墓，藏於南京博物院 箫又稱洞簫、簫管，是中國古老的吹管樂器，特徵為單管、豎吹、開管、邊稜音發聲[1]。「簫」字在唐代以前本指排簫，唐宋以來，由於單管豎吹的簫日漸流行，便稱編管簫爲排簫�...

 

 

Ramon Rodrigues De Mesquita

Ramon Informasi pribadiNama lengkap Ramon Rodrigues De MesquitaTanggal lahir 15 Juni 1988 (umur 36)Tempat lahir Sobradinho, BrazilTinggi 1,89 m (6 ft 2+1⁄2 in)[1]Posisi bermain BekInformasi klubKlub saat ini Nongbua PitchayaNomor 5Karier junior0000–2006 BrasilienseKarier senior*Tahun Tim Tampil (Gol)2006 Sobradinho Clube de Regatas Guará Bandeirantes Clube Esportivo Guará São José 2009 Legião Capital Clube de Futebol 2010 Brasília 2013 Joinville 1 (0...

Neutral Bay ferry services

Ferry route in Sydney, Australia F5 Neutral BayLocaleSydneyTransit typeCommuter ferryFleetFirst FleetOwnerSydney FerriesOperatorTransdev Sydney FerriesNo. of terminals5 Sydney Ferries services Manly Taronga Zoo Parramatta River Pyrmont Bay Neutral Bay Mosman Bay Double Bay Cockatoo Island Watsons Bay Blackwattle Bay vte Neutral Bay ferry services (numbered F5) is a commuter ferry route in Sydney, New South Wales, Australia. Part of the Sydney Ferries network, it serves several Lower North Sho...

 

 

Chinese American Museum

Museum in Los Angeles, California, United States For other uses, see Chinese American Museum (disambiguation). Chinese American Museum華美博物館Established1984Location425 North Los Angeles StreetLos Angeles, CACoordinates34°03′21″N 118°14′21″W / 34.055832°N 118.239103°W / 34.055832; -118.239103TypeChinese-American experienceand history in Southern CaliforniaWebsiteChinese American Museum official site Chinese American MuseumTraditional Chinese華�...

 

 

Bell 222/230

Family of utility helicopters Bell 222/230 A Bell 222U Role Executive/utility helicopterType of aircraft National origin United States Manufacturer Bell Helicopter First flight 13 August 1976 Introduction Bell 222: 1979Bell 230: 1991 Produced Bell 222: 1980–1991 Bell 230: 1992–1995 Number built Bell 222: 199 Bell 230: 38[1] Variants Bell 430 Developed into Bell D-292 The Bell 222 is an American twin-engine light helicopter built by Bell Helicopter. The Bell 230 is an improved deve...

Chlorophyll a

Chlorophyll a Names IUPAC name Chlorophyll a Systematic IUPAC name Magnesium [methyl (3S,4S,21R)-14-ethyl-4,8,13,18-tetramethyl-20-oxo-3-(3-oxo-3-{[(2E,7R,11R)-3,7,11,15-tetramethyl-2-hexadecen-1-yl]oxy}propyl)-9-vinyl-21-phorbinecarboxylatato(2−)-κ2N,N′] Other names α-Chlorophyll Identifiers CAS Number 479-61-8 N 3D model (JSmol) Interactive imageInteractive image ChemSpider 16736115 Y ECHA InfoCard 100.006.852 EC Number 207-536-6 PubChem CID 6433192 RTECS number FW6420000 U...

 

 

Shake It Off

Shake It OffSingel oleh Taylor Swiftdari album 1989Dirilis18 Agustus 2014 (2014-08-18)Format CD single unduhan digital Direkam15 Februari 2014 (2014-02-15)GenrePop dansaDurasi3:39LabelBig MachinePencipta Taylor Swift Max Martin Shellback Produser Max Martin Shellback Shake It Off adalah lagu karya penyanyi-penulis lagu Amerika Serikat Taylor Swift untuk album studio kelimanya, 1989 (2014). Lagu Shake It Off ditulis oleh Swift bersama dengan Max Martin dan Shellback. Lagu Shake It Of...