Starship Asterisk*

Deathfleer wrote: ↑Sat Mar 13, 2021 5:51 am
Tha area should be active, if not, the plasma cannot last for a long time...?l

https://en.wikipedia.org/wiki/Xi_Persei wrote:

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<<Menkib (Arabic for "shoulder"), Xi Persei (ξ Persei, abbreviated Xi Per, ξ Per) is a star in the constellation of Perseus. Based upon parallax measurements taken during the Hipparcos mission, it is approximately 1,200 light-years from the Sun. In Chinese, 卷舌 (Juǎn Shé), meaning Rolled Tongue, refers to an asterism consisting of Xi Persei, Nu Persei, Epsilon Persei, Zeta Persei, Omicron Persei and 40 Persei. Consequently, the Chinese name for Xi Persei itself is 卷舌三 (Juǎn Shé sān, "the Third Star of Rolled Tongue").

Menkib has a mass of some 30 solar masses and a surface temperature of 35,000 kelvins, making it one of the hottest stars that can be seen with the naked eye. The fluorescence of the California Nebula (NGC 1499) is due to this star's prodigious radiation.

Xi Persei has an apparent magnitude of +4.06 and is classified as a blue giant (spectral class O7.5III). It is intrinsically 12,700 times brighter than the Sun with absolute magnitude −5.5 in the V band. If the ultraviolet light and light from other wavelengths that emanates from Menkib is included, its total bolometric luminosity is 263,000 times that of the Sun. It is a member of the Perseus OB2 association of co-moving stars, but may be a runaway star since it is now separated by 200 pc from the association's center and has an unusually high radial velocity.>>

Deathfleer wrote: ↑Thu Mar 11, 2021 1:47 am Is there just molecules and no particles in the cloud. If so, what is the density and the size of the particles in the cloud.

A nebula (Latin for 'cloud' or 'fog';[2] pl. nebulae, nebulæ or nebulas[3][4][5][6]) is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, the term was used to describe any diffused astronomical object, including galaxies beyond the Milky Way. The Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others.

Most nebulae are of vast size; some are hundreds of light-years in diameter. A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by.[7] The Orion Nebula, the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers.[8] Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms.

Chris Peterson wrote: ↑Wed Mar 10, 2021 5:34 pm

johnnydeep wrote: ↑Wed Mar 10, 2021 4:42 pm It's amusing to me that none of the six pics of this nebula at the WikiPedia page for it look anything like California, at least not how California is normally portrayed.

I'd say the fourth one does. As does today's image.

johnnydeep wrote: ↑Wed Mar 10, 2021 4:42 pm It's amusing to me that none of the six pics of this nebula at the WikiPedia page for it look anything like California, at least not how California is normally portrayed. :ssmile:

SpaceCadet wrote: ↑Wed Mar 10, 2021 9:15 am Is Xi Persei in the photo? There are a number of blue stars here so I can't tell which one it is.