When is the best time to observe Ain?

Ain is best observed from October through December, with peak visibility during November when it transits around midnight in the Northern Hemisphere.

Where is Ain located in the sky?

Ain lies in the constellation Toro at right ascension 04h 29m and declination +19° 11′.

What telescope do I need to split Ain?

Splitting Ain requires an aperture of roughly 60 mm or larger — the components are separated by about 190.4″ at magnitudes near 3.5. The companion is about 7.1 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Ain — Stella doppia in Toro

HIP 20889; Epsilon Tauri; 74 Tauri

Magnitudine 3.5^m DoubleStar Toro (Tau) Visibile 1 Exoplanet

Mappa stellare + Lista + Piano

Su Ain

Descrizione

Ain, Epsilon Tauri, is a K-giant of spectral class G9.5 III about 147 light-years away. It is a member of the Hyades open cluster and became famous in 2007 as the first Hyades star confirmed to host an exoplanet — Ain b, a super-Jupiter of at least 7.6 Jupiter masses in a 1.6-year orbit. Ain's magnitude is 3.53 and its color is a warm pale orange.

Consigli per l'osservazione

Ain marks the northern eye of the Taurus bull, above the V of the Hyades. In any small binoculars it appears as a warm yellow-orange point surrounded by dozens of fainter Hyades members. Ain is one of the "bull's eyes," with Aldebaran marking the southern eye. Best observed November through March.

Storia

The name Ain is Arabic for "eye," specifically designating the bull's northern eye. The pairing of Aldebaran ("the follower") and Ain ("the eye") in Taurus dates to pre-Islamic Arabic astronomy. The IAU adopted both names in 2016.

Curiosità

Ain's planet was the first exoplanet discovered around a Hyades member — a milestone because the Hyades is the closest well-studied open cluster, allowing direct comparison of planetary-system outcomes in a co-evolving population of stars. The 625-million-year-old age of the Hyades means Ain b is a "young Jupiter," useful for studying how giant planets evolve over cosmic time.

Osservare

1Proprietà fisiche

Magnitudine 3.53

Tipo spettrale G9.5III CN0.5 gigante

Colore della stella Arancione (B-V 1.01)

Distanza 147 ly

2Posizione e identificatori

RA 04h 28m 37.0s

Dec +19° 10' 49.0"

Costellazione Toro (Tau)

HR 1409

HIP 20889

HD 28305

SAO 93954

Bayer Epsilon

Flamsteed 74 Tau

SIMBAD Wikipedia

3Facilità di separazione

Principale 3.5 mag Compagna 10.6 mag Separazione 190.4″

Accedi e configura la tua attrezzatura e località predefinita per vedere una riga personalizzata.

Telescopio	Bortle 3	Bortle 4	Bortle 5
Rifrattore 80 mm Rifr. 80mm	Medio	Diff.+	Diff.
Newton 150 mm Newt. 150mm	Facile	Medio+	Medio
Celestron C8 (SCT 203 mm) C8 203mm	Facile	Facile	Medio+

Facile Medio Difficile Molto difficile Impossibile

Bortle 3 = rurale · 4 = periferia · 5 = suburbano

4Visibilità

Imposta una località nelle impostazioni per vedere i dati di visibilità.

Periodo migliore Oct – Dec (peak: Nov)

5Sistema stellare multiplo

Separazione 190.4″

Mag compagna 10.6

Angolo di posizione 269°

Colori delle stelle A: Arancione

Scopritore BUP 61

Separazione nel tempo

Misurato 1894 → 2015 (121 y)

Deriva separazione 179.9" → 190.4" (+10.50")

Tasso +0.0868" / y

Deriva PA 268° → 269° (+1°, +0.008°/y)

Movimento apparente significativo su scala temporale umana — vale la pena rivisitarle tra un decennio.

Misurato dall'archivio osservativo WDS. Non è stata derivata alcuna soluzione orbitale — molto probabilmente il periodo è troppo lungo per adattare un'orbita all'arco di misurazioni disponibile.