Rukbatについて
説明
Rukbat, Alpha Sagittarii, is a blue-white B8 V main-sequence star about 170 light-years away, notable for being the "Alpha" designation of Sagittarius despite being far from the brightest star in the constellation. It shines at magnitude 3.97, and the Sagittarius alpha status reflects Bayer's 17th-century labeling rather than modern brightness rankings. Rukbat has a weak infrared excess consistent with a circumstellar debris disk.
観測のコツ
Rukbat lies in the southern portion of Sagittarius, south of the Teapot asterism. It is a crisp blue-white naked-eye point. Finding Rukbat requires tracing Sagittarius far enough south to skirt the southernmost parts of the Milky Way. Best observed from mid-latitudes during June-September.
歴史
The name Rukbat comes from the Arabic "rukbat al-rāmī," meaning "the knee of the archer." The IAU adopted the name in 2016. The "Alpha" label dates from Bayer's 1603 Uranometria; Bayer assigned Greek letters partly by position in the figure, not purely by brightness.
豆知識
Rukbat's debris disk resembles our own Kuiper Belt scaled up — a young analog that may preserve clues about planetary formation timescales. Despite being the alpha star, Rukbat would be classed merely as one of Sagittarius's many modest B-type stars if modern catalogs had been first to label it.
観測
1物理的性質
3見つけやすさ
| 機材 | ボートル3 | ボートル4 | ボートル5 |
|---|---|---|---|
| 肉眼 肉眼 | 容易 | 普通+ | 普通 |
| 50mmファインダー 50mmファインダー | 容易 | 容易 | 容易 |
| 150mm望遠鏡 150mm望遠鏡 | 容易 | 容易 | 容易 |
ボートル3＝田舎 · 4＝郊外 · 5＝住宅地
5サーベイ画像
サーベイ画像を読み込み中…
探究
7
サイズ比較
8
恒星を比較
9
スペクトル分類
11
恒星の進化
12
黒体放射スペクトル
13
恒星吸収スペクトル
スペクトル型に基づくシミュレーション吸収スペクトル。線にマウスを合わせると元素を識別できます。
14
恒星核融合
発見
15恒星メモ
近くの天体
数度以内にある他の対象 — 望遠鏡を少し動かして探索を続けましょう。
可視性スコアは150 mmニュートン・ボートル4を前提としています。
