When is the best time to observe Talitha?

Talitha is best observed from December through February, with peak visibility during January when it transits around midnight in the Northern Hemisphere.

Where is Talitha located in the sky?

Talitha lies in the constellation おおぐま at right ascension 08h 59m and declination +48° 02′.

What telescope do I need to split Talitha?

Splitting Talitha requires an aperture beyond typical amateur scopes — even 500 mm struggles against the primary's glare — the components are separated by about 0.9″ at magnitudes near 3.1. The companion is about 7.0 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Talitha — おおぐまの二重星

HIP 44127; Iota Ursae Majoris; 9 Ursae Majoris

等級 3.1^m DoubleStar おおぐま (UMa) 可視

星図 + リスト + 計画

Talithaについて

説明

Talitha, Iota Ursae Majoris, is a quadruple star system lying 47 light-years away in the west of Ursa Major. The primary is an A7V white dwarf of about 1.7 solar masses, orbited distantly by a pair of M-dwarf red-dwarf binaries. Talitha shines at combined magnitude 3.14 and forms one of the three "leaps of the gazelle" asterism with Alkaphrah (Kappa UMa) and Alhaud stars — the marks of the bear's "paws" in classical Arabic astronomy.

観測のコツ

Find Talitha west of the main Big Dipper pattern, forming a prominent pair with nearby Kappa UMa (about 0.7 degrees south). Together they make the First Leap of the Gazelle. The bright primary is an easy naked-eye object; the M-dwarf companion binary is around 4 arcseconds out at magnitude 10 — a challenge requiring 10-inch apertures and steady seeing. Circumpolar at mid-northern latitudes.

歴史

The name Talitha derives from the Arabic "al-qafzah al-thālithah," meaning "the third leap" (of the gazelle, a pre-Islamic asterism). The IAU adopted "Talitha" specifically for Iota UMa A in 2016. The companion pair was resolved by Otto Struve in the 1840s.

豆知識

The Three Leaps of the Gazelle asterism is one of the oldest recognized patterns in Ursa Major — older than the Big Dipper itself in some traditions. Talitha is one of the few naked-eye A-type stars close enough to have a directly measured angular diameter by optical interferometry. The full four-star system spans about 200 AU at its present epoch.

観測

1物理的性質

等級 3.14

スペクトル型 A7V(n)

星の色黄白 (B-V 0.19)

距離 47 ly

2位置と識別子

RA 08h 59m 12.4s

Dec +48° 02' 30.0"

星座おおぐま (UMa)

HR 3569

HIP 44127

HD 76644

SAO 42630

Bayer Iota

Flamsteed 9 UMa

Double Cat 7114

SIMBAD Wikipedia

3分離しやすさ

主星 3.1 mag 伴星 10.1 mag 離角 0.9″

サインインし、機材と既定の場所を設定するとパーソナライズ行が表示されます。

望遠鏡	ボートル3	ボートル4	ボートル5
80 mm 屈折 80mm 屈折	極難	極難	極難
150 mm ニュートン 150mm ニュートン	極難	極難	極難
Celestron C8 (203 mm SCT) C8 203mm	極難	極難	極難

簡単普通難しい非常に難不可能

ボートル3＝田舎 · 4＝郊外 · 5＝住宅地

ボートル3でも、一般的なアマチュア望遠鏡の限界を超えています。

4可視性

設定で観測地を設定すると可視性データが表示されます。

観測好期 Dec – Feb (peak: Jan)

5多重星系 Quadruple

成分 4 (quadruple)

成分ID AB

離角 0.9″

伴星等級 10.1

位置角 206°

星の色 A: 黄白

発見者 HU 628

メモ

BC 10.8, 11.0, 39.69y, a = 0.68". BC is dM1. BCxA: 817.91y, a = 9.092". Separation rapidly decreasing. ADS 7114Aa, | 11.02y, a = 90.354". This is the SB pair.