| 翻訳と辞書 |
| double cluster ： ウィキペディア英語版 |
double cluster
The Double Cluster (also known as Caldwell 14) is the common name for the naked-eye open clusters NGC 869 and NGC 884 (often designated h Persei and χ Persei, respectively),〔Some confusion surrounds what Bayer intended by these designations. It is sometimes claimed that Bayer could not have resolved the pair into two patches of nebulosity, and that Chi refers to the Double Cluster and h to a nearby star; see Stephen James O'Meara and Daniel W.E. Green, 2003, "The Mystery of the Double Cluster", ''Sky and Telescope'', Vol. 105, No. 2 (February 2003), p. 116–119. Bayer's ''Uranometria'' chart for Perseus does not show them as nebulous objects, but his chart for Cassiopeia does, and they are described as ''Nebulosa Duplex'' in Schiller's ''Coelum Stellatum Christianum'', which was assembled with Bayer's help; see Morton Wagman, ''Lost Stars'', McDonald & Woodward, 2003, ISBN 0939923785, p. 240.〕 which are close together in the constellation Perseus. NGC 869 and NGC 884 both lie at a distance of 7500 light years.〔(【引用サイトリンク】url=http://iopscience.iop.org/1538-3881/122/1/248/fulltext/201081.text.html )〕 NGC 869 has a mass of 3700 solar masses and NGC 884 weighs in at 2800 solar masses; however, later research has shown both clusters are surrounded with a very extensive halo of stars, with a total mass for the complex of at least 20,000 solar masses.〔(【引用サイトリンク】url=http://adsabs.harvard.edu/abs/2010ApJS..186..191C )〕 Based on their individual stars, the clusters are relatively young, both 12.8 million years old.〔(【引用サイトリンク】url=http://www.noao.edu/education/arbsefolder/files/apjpaper.pdf )〕 In comparison, the Pleiades have an estimated age ranging from 75 million years to 150 million years. There are more than 300 blue-white super-giant stars in each of the clusters. The clusters are also blueshifted, with NGC 869 approaching Earth at a speed of and NGC 884 approaching at a similar speed of .〔(【引用サイトリンク】url=http://cds.aanda.org/index.php?Itemid=129&option=com_article&access=bibcode&bibcode=2005A%25252526A...438.1163K )〕 Their hottest main sequence stars are of spectral type B0.
==Mythology==
Perseus is the mythological symbol of adventure. Perseus was born the son of Zeus (The "Father of Gods and men") and the mortal Danae. He was a demigod but not immortal. Perseus was challenged by King Polydectes of Seriphos to slay one of the Gorgons (Medusa), whose gaze turned an on-looking victim into stone. Athena, Hermes, and other gods gave Perseus a helmet, a shield, and a curved sword with studded jewels on its handle to aid him in the challenge. Along with beheading Medusa, Perseus performed other heroic deeds as well, such as saving Andromeda who was a princess chained to a rock as a sacrifice to a sea monster. Due to his great accomplishments, the gods placed Perseus among the stars, with the head of Medusa in one hand and the jeweled sword in the other. The Double Cluster represents the jeweled handle of Perseus’s sword.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「double cluster」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|