Page 140 - spectroscopic-atlas-5_0-english_Neat

Spectroscopic Atlas for Amateur Astronomers 140

spectral class can be found. Anyway as the first option for amateurs remains clearly the
spectroscopic age-estimation based on the spectral class.

27.6 The Pleiades - Analysis by Individual Spectra

The approximately 390 light years distant Pleiades (M45) are so nearby, that this object
appears more as a small constellation, rather than an open cluster. With the unaided eye,
we see here just the brightest 6 up to max. 10 stars which astonishingly belong all to the
middle to late B-Class. Their visibility depends mainly on the seeing and the current bright-
ness of the Be-star Pleione.

Star Flamsteed HD No. Apparent Abs. [*] Spectr. Remarks (CDS)
name No. brightn. brightn. Class

Alcyone 25 Tau (η) 23630 ~2.87m –2.74 B7 IIIe Be- and Multiple star
–2.00 B8 III Binary star system
Atlas 27 Tau 23850 ~3.63m –1.84 B6 IIIe Be Star
–1.83 B8 III Binary star system
Electra 17 Tau 23302 ~3.7m –1.58 B6 IVe Variable β Cep Type
–1.31 B6 IV Binary star system
Maia 20 Tau 23408 ~3.87m –0.58 B8 V ne Be Star
–0.28 B7 IV Variable
Merope 23 Tau 23480 ~4.18m + 0.01 B8 V
+ 0.05 B8 V Variable
Taygeta 19 Tau 23338 ~4.3m

Pleione 28 Tau 23862 ~5.09m

Celaeno 16 Tau 23288 ~5.46m

18 Tau 23324 ~5.64m

Asterope 21 Tau 23432 ~5.76m

[*] Abt/Levato [328], other data CDS [500]

Image: Pleiades labelled with Flamsteed numbers (M. Huwiler)

28

27 18
25 21

20
19

23 16
17