westerlund 1 bks as

Inilah Bintang Terbesar Sejagad yang Mengalahkan NML Cygni

Kluster bintang Westerlund, lokasi bintang terbesar sejagad yang baru diketahui. Kredit: NASA

Seperti yang kita ketahui saat ini, bintang terbesar di alam semesta adalah NML Cygni. Namun, ada yang lebih besar lagi. Yakni Westerlund 1 BKS AS.

Sebelumnya juga pernah ada bintang terbesar bernama VY Canis Majoris, namun kemasifannya dikalahkan NML Cygni. Saat ini, NML Cygni mungkin bukan lagi yang terbesar sejagad.

Bintang Westerlund 1 BKS AS atau juga bisa disebut Westerlund 1 W26, adalah bintang yang terletak pada jarak 16.000 tahun cahaya dari Bumi (1 tahun cahaya = 9,4 triliun kilometer).

Bintang ini terletak di kluster atau gugus bintang Westerlund di konstelasi Ara. Radius bintang Westerlund 1 BKS AS adalah 1.951 hingga 2.544 radius Matahari atau 16,64 miliar kali lebih besar dari Matahari.

Jika Westerlund 1 BKS AS ditempatkan di pusat tata surya kita, permukaannya akan mencapai Saturnus. Artinya, Bumi bukan planet layak huni lagi.

Diameter bintang ini adalah 3,54 miliar kilometer, sedangkan NML Cygni hanya berdiameter 2,29 miliar kilometer. Bintang ini juga merupakan bintang hiper-raksasa merah.

Dalam urutan bintang terbesar di alam semesta yang diketahui, Westerlund 1 BKS AS berada di urutan pertama, diikuti UY Scuti di urutan kedua. NML Cygni di urutan ketiga sedangkan VY Canis Majoris di urutan kedelapan.

https://www.youtube.com/watch?v=E8uU6nEklzc

V354 Cephei
V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located approximately 9,000 light-years away from our Sun, and is currently considered one of the largest known stars, with a radius estimate of 1,520 times that of the Sun, or 1,060,000,000 km at its greatest extent. If it were placed in the center of the Solar System, it would extend to 7 AU, between the orbits of Jupiter and Saturn.

The luminosity, and hence the size, of V354 Cep are disputed. Levesque et al 2005, find a high luminosity and consequently very large size of 1,520 R_☉, making it one of the List of largest stars. From the same data, Mauron et al 2011 derive a much smaller luminosity of 76,000 L_☉, which implies a much smaller size around 690 R_☉. They note the discrepancy but are unable to explain it.^[7]

There are similar differences in the visual extinctions derived, between two and six magnitudes.

V354 Cephei

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Cepheus
Right ascension	22h 33m 34.643s[1]
Declination	+58° 53′ 47.05″[1]
Apparent magnitude (V)	10.82 to 11.35[2]
Characteristics
Spectral type	M2.5 Iab[3]
B−V color index	+3.18[4]
Variable type	LC[2]
Astrometry
Distance	~9,000[5] ly (3,500 pc)
Absolute magnitude (MV)	-7.57 (variable)[4]
Details
Radius	1,520[6] R☉
Luminosity	76,000[7] - 369,000[6] L☉
Surface gravity (log g)	−0.5[6] cgs
Temperature	3,650[6] K
Other designations
V354 Cep, Case 75,2MASS J22333464+5853470,IRAS 22317+5838
Database references
SIMBAD	data

Orion Nebula( Messier 42, M42, or NGC 1976)

Orion Nebula (also known as Messier 42, M42, or NGC 1976) 

The entire Orion Nebula in a composite image of visible light and infrared.

The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion.^[b] It is one of the brightest nebulae, and is visible to the naked eye in the night sky. M42 is located at a distance of 1,344 ± 20 light years^[3][6] and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light years across. It has a mass of about 2000 times the mass of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula.^[7]

The constellation of Orion with the Orion Nebula (lower middle)

The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features.^[8] The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust. Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula.

Optical images reveal clouds of gas and dust in the Orion Nebula; an infrared image (right) reveals the new stars shining within.

The Nebula is part of a much larger nebula that is known as the Orion Molecular Cloud Complex. The Orion Molecular Cloud Complex extends throughout the constellation ofOrion and includes Barnard's Loop, the Horsehead Nebula, M43, M78, and the Flame Nebula. Stars are forming throughout the entire Cloud Complex, but most of the young stars are concentrated in dense clusters like the one illuminating the Orion Nebula