Étoile variable irrégulière

Une (étoile) variable irrégulière est un type d'étoile variable dont les variations de luminosité ne présentent pas de périodicité définie. Il y a deux sous-types principaux de variables irrégulières : les variables irrégulières éruptives et les variables irrégulières pulsantes.

Les variables irrégulières éruptives sont divisées en trois catégories[réf. nécessaire] :

  • Les variables du groupe I sont séparées en deux sous-groupes IA (types spectraux O à A) et IB (types spectraux F à M).
  • Les variables appelées IN (irregular nebulous) ou variables de type Orion, spécifiques aux régions de formation d'étoiles, peuvent varier de plusieurs magnitudes avec des changements rapides allant jusqu'à 1 magnitude en 1 à 10 jours, sont de façon similaire séparées en fonction du type spectral en sous-groupes INA et INB, mais avec un sous-groupe supplémentaire, INT, pour les étoiles de type T Tauri, ou INT(YY) pour les étoiles de type YY Orionis.
  • La troisième catégorie d'irrégulières éruptives sont les étoiles IS, qui présentent des variations rapides de 0,5 à 1 magnitude en quelques heures ou jours ; de nouveau, elles sont séparées en sous-groupes ISA et ISB.

Les géantes ou supergéantes irrégulières pulsantes, ou variables irrégulières à longue période, sont toutes de type spectral tardif (K, M, C, ou S) et sont classées en type L-LB pour les géantes et LC pour les supergéantes. La question de savoir combien de ces dernières sont en fait des variables semi-régulières qui demandent simplement plus d'analyses, reste ouverte[1].

Voir aussi

Références

  1. ↑ Gerry Arlen Good, Observing Variable Stars, Springer Science, (présentation en ligne)

Read other articles:

Confine tra il Mozambico e il Sudafrica

Confine tra il Mozambico e il Sudafrica     Mozambico      SudafricaDati generaliStati Mozambico Sudafrica Lunghezza496 km InterruzioniIl confine consiste in due segmenti separati da eSwatini Dati storiciIstituito nel1869 Causa istituzioneTrattato anglo-portoghese Attuale dal1940 ManualeIl confine tra il Mozambico e il Sudafrica è diviso in due segmenti, separati dal regno di eSwatini. Il segmento settentrionale, corre da nord a sud...

 

العلاقات الزامبية الليختنشتانية

العلاقات الزامبية الليختنشتانية زامبيا ليختنشتاين   زامبيا   ليختنشتاين تعديل مصدري - تعديل   العلاقات الزامبية الليختنشتانية هي العلاقات الثنائية التي تجمع بين زامبيا وليختنشتاين.[1][2][3][4][5] مقارنة بين البلدين هذه مقارنة عامة ومرجعية لل�...

 

Meghna River

River in Bangladesh Meghna redirects here. For other uses, see Meghna (disambiguation). Meghna (Bengali: মেঘনা নদী)Lower MeghnaLocationCountriesBangladeshPhysical characteristicsSource  • locationChandpur (Confluence of Padma and Upper Meghna) • coordinates23°13′11.1792″N 90°37′49.5708″E / 23.219772000°N 90.630436333°E / 23.219772000; 90.630436333 • elevation0.5 m (1 ft 8...

Calcio di rigore

Disambiguazione – Se stai cercando la sequenza di tiri che decide il vincitore al termine di un incontro ad eliminazione diretta, vedi Tiri di rigore. Voce principale: Regole del gioco del calcio. Lothar Matthäus esegue un calcio di rigore in Germania-Bulgaria 1-2 ai Mondiali 1994 Il calcio di rigore, o più semplicemente rigore, è la ripresa di gioco utilizzata nel calcio quando un calciatore commette nei confronti di un avversario, nella propria area di rigore e con il pallone in gioco...

 

Дракино (Лискинский район)

У этого термина существуют и другие значения, см. Дракино. СелоДракино 51°08′27″ с. ш. 39°24′31″ в. д.HGЯO Страна  Россия Субъект Федерации Воронежская область Муниципальный район Лискинский Сельское поселение Дракинское История и география Основан 1770 Часовой по�...

 

Paul J. Weitz

American astronaut (1932–2017) Paul WeitzBornPaul Joseph Weitz(1932-07-25)July 25, 1932Erie, Pennsylvania, U.S.DiedOctober 22, 2017(2017-10-22) (aged 85)Flagstaff, Arizona, U.S.EducationPennsylvania State University (BS)Naval Postgraduate School (MS)AwardsNASA Distinguished Service MedalAir MedalSpace careerNASA astronautRankCaptain, USNTime in space33d 1h 13mSelectionNASA Group 5 (1966)Total EVAs1Total EVA time1h 36mMissionsSkylab 2STS-6Mission insignia RetirementMay 1994 Paul Joseph...

Stamford Bridge (stadium)

Association football stadium in London For other uses, see Stamford Bridge (disambiguation). Stamford BridgeThe BridgeStamford Bridge aerial view (2023)Full nameStamford BridgeLocationFulham,London, SW6EnglandPublic transit Fulham BroadwayOwnerChelsea Pitch OwnersOperatorChelseaExecutive suites51Capacity40,343[4]Record attendance82,905 (Chelsea–Arsenal, 12 October 1935)[3]Field size113 by 74 yards (103.3 m × 67.7 m)[4]SurfaceGrassMaster by Tarkett Spo...

 

2012 Cyprus terrorist plot

2012 Cyprus terrorist plotPart of the Iran–Israel proxy conflictLocationCyprusDateJuly 7, 2012Attack typeNoneWeaponNoneVictimsNonePerpetratorsHezbollah vteIran–Israel proxy conflict2024 Iran–Israel conflict Iranian consulate airstrike in Damascus Iranian seizure of the MSC Aries 2024 Iranian strikes in Israel 2024 Israeli strikes on Iran Hezbollah–Israel conflict South Lebanon conflict Shebaa Farms conflict January 2015 Shebaa Farms incident Operation Northern Shield April 2023 shelli...

 

SMK Katolik Santo Mikael Surakarta

SMK Katolik Santo MikaelInformasiDidirikan1962JenisSwasta, Katolik, Yesuit, Teknik Mesin, SMK PKKepala SekolahDrs. Stepanus Maryata, M.PdAlamatLokasiJl. Mojo No.1 Karangasem, Laweyan, Surakarta, Jawa Tengah, IndonesiaSitus webSMK MikaelMotoMotoAd Majorem Dei Gloriam SMK Katolik St. Mikael Surakarta adalah sebuah Sekolah Menengah Kejuruan di Surakarta, Indonesia. Penyelenggaraan sekolah ini berada di bawah Yayasan Karya Bakti Surakarta. Kolese ini biasa disebut dengan singkatan MICO ...

سياسة المغرب المائية

المغرب: السياسة المائية الموارد المائية الموارد السطحية 15 مليار متر3 [1] الموارد الباطنية 5 ملايير متر3 [1] الموارد الكلية 20 مليار متر3 (الرتبة 114)[2] الموارد المائية نسبة الولوج إلى الماء الصالح للشرب 82% (2004) نسبة الولوج إلى شبكة المياه العادمة 76% (1996) استمرارية الماء...

 

Frida Richard

Austrian actress Frida RichardRichard c. 1930BornFriederike Raithel(1873-11-01)1 November 1873Vienna, Austria-HungaryDied12 September 1946(1946-09-12) (aged 72)Salzburg, AustriaOccupationActressYears active1908–1944SpouseFritz RichardChildren3 Frida Richard (born Friederike Raithel, 1 November 1873 – 12 September 1946) was an Austrian actress. Selected filmography The Sin of Helga Arndt (1916) The Queen's Love Letter (1916) The Marriage of Luise Rohrbach (1917) The Diamond Found...

 

Pertumbuhan fotovoltaik

Kapasitas PV yang ditambahkan setiap negara pada tahun 2017 (dalam persen terhadap total global, dikumpulkan berdasarkan wilayah)[1]   Cina (55.8%)  Jepang (7.4%)  Korea Selatan (1.3%)  India (9.6%)  Australia (1.3%)  Amerika Serikat (11.2%)  Brazil (0.9%)  Turki (2.7%)  Jerman (1.9%)  Britania Raya (0.9%)  Perancis (0.9%)  Belanda (0.9%)  Eropa lainnya (1...

Tân An

For other uses, see Tân An. City in Long An, VietnamTân An Thành phố Tân AnCity (Class-2)Tân An CityCountry VietnamProvinceLong AnArea • Total81.94 km2 (31.64 sq mi)Population (2018) • Total215,250 • Density2,277.4/km2 (5,898/sq mi) Tân An is the capital city of Long An Province in Mekong Delta region of Vietnam. It was upgraded from town status to city status on 26 August 2009. The population of Tân An is 165,214 as o...

 

Reproductive Health Act

This article is about a New York state law. For the Philippine law also known as the Reproductive Health Act, see Responsible Parenthood and Reproductive Health Act of 2012. Reproductive Health ActNew York State LegislatureFull nameReproductive Health ActAcronymRHAIntroducedJanuary 9, 2019Assembly votedJanuary 22, 2019 (92-47)Senate votedJanuary 22, 2019 (38-24)Signed into lawJanuary 22, 2019Sponsor(s)Deborah J. Glick (Assembly),Liz Krueger (Senate)GovernorAndrew CuomoStatus: Current legislat...

 

Risk assessment

Estimation of risk associated with exposure to a given set of hazards This article's lead section may be too short to adequately summarize the key points. Please consider expanding the lead to provide an accessible overview of all important aspects of the article. (February 2021) Risk assessment determines possible mishaps, their likelihood and consequences, and the tolerances for such events.[1] The results of this process may be expressed in a quantitative or qualitative fashion. R...

Richie Cunningham

Fictional character from Happy Days This article is about the fictional character. For the football player of the same name, see Richie Cunningham (American football). For other people, see Richard Cunningham. Fictional character Richie CunninghamRichie talking to Mary Lou MilliganFirst appearanceAll The WayLast appearancePassages Part 2Created byGarry MarshallPortrayed byRon HowardIn-universe informationFull nameRichard J. CunninghamOccupationStudent, reporter, soldier, screenwriterFamily Ho...

 

Cristo Rey (film)

Cristo ReyPoster filmSutradaraLeticia TonosDitulis olehLeticia TonosAlejandro AndújarPemeranAkari EndoSinematograferChicca UngaroTanggal rilis 10 September 2013 (2013-09-10) (FFIT) Durasi96 menitNegaraRepublik DominikaBahasaSpanyol Cristo Rey adalah sebuah film drama Republik Dominika 2013 yang ditulis dan disutradarai oleh Leticia Tonos. Film tersebut ditayangkan dalam sesi Sinema Dunia Kontemporer di Festival Film Internasional Toronto 2013.[1][2] Film tersebut ter...

 

Huddersfield

Huddersfield Population (Sensus tahun 2011) Ref. grid OS SE145165 Distrik metropolitan Kirklees County metropolitan Yorkshire Barat Region Negara konstituen Inggris Negara berdaulat Britania Raya Kota pos HUDDERSFIELD Distrik kode pos HD1-5, HD7-8 Kode telepon 01484 Polisi Pemadam kebakaran Ambulans Parlemen UE Yorkshire dan Humber Parlemen Britania Raya Huddersfield Daftar tempat: Britania Raya • Inggris • Huddersfield merupaka...

Семёнов, Павел Владимирович

В Википедии есть статьи о других людях с такой фамилией, см. Семёнов; Семёнов, Павел. Павел Владимирович Семёнов Глава администрации города Новочебоксарск 2020 — 2021 Рождение 7 декабря 1976(1976-12-07) (47 лет)Канаш, Чувашская АССР, РСФСР, СССР Отец Семёнов, Владимир Николаевич Пар�...

 

Sarah Bernhardt - La più grande attrice di tutti i tempi

Questa voce sull'argomento film drammatici è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Sarah Bernhardt - La più grande attrice di tutti i tempiGlenda Jackson nei panni di Sarah BernhardtTitolo originaleThe Incredible Sarah Paese di produzioneRegno Unito Anno1976 Durata106 min Generedrammatico RegiaRichard Fleischer SceneggiaturaRuth Wolff FotografiaChristopher Challis MontaggioJohn Jympson MusicheElmer Bernstein ScenografiaElliot Scott, Norman Re...