Английская Википедия:CW Leonis
Шаблон:Short description Шаблон:Starbox begin Шаблон:Starbox image Шаблон:Starbox observe Шаблон:Starbox character Шаблон:Starbox astrometry Шаблон:Starbox detail Шаблон:Starbox catalog Шаблон:Starbox reference Шаблон:Starbox end
CW Leonis or IRC +10216 is a variable carbon star that is embedded in a thick dust envelope. It was first discovered in 1969 by a group of astronomers led by Eric Becklin, based upon infrared observations made with the Шаблон:Convert Caltech Infrared Telescope at Mount Wilson Observatory. Its energy is emitted mostly at infrared wavelengths. At a wavelength of 5 μm, it was found to have the highest flux of any object outside the Solar System.[1]
Properties
CW Leonis is believed to be in a late stage of its life, blowing off its own sooty atmosphere to form a white dwarf. Based upon isotope ratios of magnesium, the initial mass of this star has been constrained to lie between 3–5 solar masses. The mass of the star's core, and the final mass of the star once it becomes a white dwarf, is about 0.7–0.9 solar masses.[3] Its bolometric luminosity varies over the course of a 649-day pulsation cycle, ranging from a minimum of about 6,250 times the Sun's luminosity up to a peak of around 15,800 times. The overall output of the star is best represented by a luminosity of Шаблон:Solar luminosity.[4] The brightness of the star varies by about two magnitudes over its pulsation period, and may have been increasing over a period of years. One study finds an increase in the mean brightness of about a magnitude between 2004 and 2014.[5] Many studies of this star are done at infrared wavelengths because of its very red colour; published visual magnitudes are uncommon and often dramatically different. The Guide Star Catalog from 2006 gives an apparent visual magnitude of 19.23.[6] The ASAS-SN variable star catalog based on observations from 2014 to 2018 reports a mean magnitude of 17.56 and an amplitude of 0.68 magnitudes.[7] An even later study gives a mean magnitude of 14.5 and an amplitude of 2.0 magnitudes.[8]
The carbon-rich gaseous envelope surrounding this star is at least 69,000 years old and the star is losing about Шаблон:Nowrapsolar masses per year.[4] The extended envelope contains at least 1.4 solar masses of material.[9] Speckle observations from 1999 show a complex structure to this dust envelope, including partial arcs and unfinished shells. This clumpiness may be caused by a magnetic cycle in the star that is comparable to the solar cycle in the Sun and results in periodic increases in mass loss.[10]
Various chemical elements and about 50 molecules have been detected in the outflows from CW Leonis, among others nitrogen, oxygen and water, silicon and iron. One theory was that the star was once surrounded by comets that melted once the star started expanding,[11] but water is now thought to form naturally in the atmospheres of all carbon stars.[12]
Distance
If the distance to this star is assumed to be at the lower end of the estimate range, 120 pc, then the astrosphere surrounding the star spans a radius of about 84,000 AU. The star and its surrounding envelope are advancing at a velocity of more than 91 km/s through the surrounding interstellar medium.[9] It is moving with a space velocity of [U, V, W] = [[[:Шаблон:Nowrap]], Шаблон:Nowrap, Шаблон:Nowrap] km s−1.[3]
Companion
Several papers have suggested that CW Leonis has a close binary companion.[5] ALMA and astrometric measurements may show orbital motion. The astrometric measurements, combined with a model including the companion, provide a parallax measurement showing that CW Leonis is the closest carbon star to the Earth.[13] Шаблон:Clear left
See also
References
External links
- Water Found Around Nearby Star CW Leonis Astronomy Picture of the Day July 16, 2001
- Variations in the dust envelope around IRC +10216 revealed by aperture masking interferometry
- http://jumk.de/astronomie/special-stars/cw-leonis.shtml
- Шаблон:WikiSky
- ↑ Ошибка цитирования Неверный тег
<ref>; для сносокapj158_L133не указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокlinearне указан текст - ↑ 3,0 3,1 Ошибка цитирования Неверный тег
<ref>; для сносокaaa518не указан текст - ↑ 4,0 4,1 Ошибка цитирования Неверный тег
<ref>; для сносокaaa20120110не указан текст - ↑ 5,0 5,1 Ошибка цитирования Неверный тег
<ref>; для сносокhyosun2015не указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокgscне указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокasassnне указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокcatalinaне указан текст - ↑ 9,0 9,1 Ошибка цитирования Неверный тег
<ref>; для сносокapjl711_2_L53не указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокapj678_1_303не указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокfordне указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокlombaertне указан текст - ↑ Ошибка цитирования Неверный тег
<ref>; для сносокsozettiне указан текст
- Английская Википедия
- Страницы с неработающими файловыми ссылками
- Carbon stars
- Protoplanetary nebulae
- Leo (constellation)
- Astronomical objects discovered in 1969
- Mira variables
- Objects with variable star designations
- IRAS catalogue objects
- 2MASS objects
- Emission-line stars
- Страницы, где используется шаблон "Навигационная таблица/Телепорт"
- Страницы с телепортом
- Википедия
- Статья из Википедии
- Статья из Английской Википедии
- Страницы с ошибками в примечаниях
