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Post Info TOPIC: The Pleiades
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RE: The Pleiades
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Pleiadesb.jpg 


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Blobrana


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Astronomy video Pleiades by telescope



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Blobrana


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HD 23514
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Title: A Substellar Companion to the Dusty Pleiades Star HD 23514
Authors: David R. Rodriguez, Christian Marois, B. Zuckerman, Bruce Macintosh, Carl Melis

With adaptive optics imaging at Keck observatory, we have discovered a substellar companion to the F6 Pleiades star HD 23514, one of the dustiest main-sequence stars known to date (L_{IR}/L_{*}~2%). This is one of the first brown dwarfs discovered as a companion to a star in the Pleiades. The 0.06 Solar mass late-M secondary has a projected separation of ~360 AU. The scarcity of substellar companions to stellar primaries in the Pleiades combined with the extremely dusty environment make this a unique system to study.

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Blobrana


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Title: A new flare star member candidate in the Pleiades cluster
Authors: M. Moualla, T. O. B. Schmidt, R. Neuhäuser, V. V. Hambaryan, R. Errmann, L. Trepl, Ch. Broeg, T. Eisenbeiss, M. Mugrauer, C. Marka, C. Adam, C. Ginski, T. Pribulla, S. Rätz, J. Schmidt, A. Berndt, G. Maciejewski, T. Röll, M. M. Hohle, N. Tetzlaff, S. Fiedler, S. Baar

We present a new flare star, which was discovered during our survey on a selected field at the edge of the Pleiades cluster. The field was observed in the period 2007 - 2010 with three different CCD-cameras at the University Observatory Jena with telescopes from 25 to 90 cm. The flare duration is almost one hour with an amplitude in the R-band of about 1.08 mag. The location of the flare star in a colour-magnitude diagram is consistent with age and distance of the Pleiades. In the optical PSF of the flare star there are two 2MASS objects (unresolved in most images in the optical Jena PSF), so it is not yet known which one of them is responsible for this flare. The BVRIJHK colours yield spectral types of M1 and M2 with extinction being A_V=0.231±0.024 mag and A_V=0.266±0.020 for those two stars, consistent with the Pleiades cluster.

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Title: Taurus stars membership in Pleiades open cluster
Authors: A. L. Tadross, M. A. Hanna, N. S. Awadalla
(Version v2)

In this paper, we study the characteristics and physical properties of the young open cluster Pleiades (NGC 1432; M45; Melotte 22; Seven Sisters) using Near Infra Red, JHK pass bands. Our results have been compared with those found in optical, UBV, newly observations. The membership validity of some variable binary stars, which are Located in Taurus constellation, and their relation with Pleiades cluster have been achieved.

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Blobrana


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One of the most stunning sights in the heavens that you may enjoy without the benefit of a telescope is the Pleiades star cluster. This shining group of six +2nd magnitude stars  are compacted close together and ride high in the winter sky as seen from mid-northern latitudes.
Be sure not to miss the Pleiades if you have never noticed them before. They are a showpiece you will likely want to point out to your family and friends.
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9 Oct 2008

Title: The Pleiades: the celestial herd of ancient timekeepers
Authors: Amelia Sparavigna

In the ancient Egypt seven goddesses, represented by seven cows, composed the celestial herd that provides the nourishment to her worshippers. This herd is observed in the sky as a group of stars, the Pleiades, close to Aldebaran, the main star in the Taurus constellation. For many ancient populations, Pleiades were relevant stars and their rising was marked as a special time of the year. In this paper, we will discuss the presence of these stars in ancient cultures. Moreover, we will report some results of archeoastronomy on the role for timekeeping of these stars, results which show that for hunter-gatherers at Palaeolithic times, they were linked to the seasonal cycles of aurochs.

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Pleiades
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Title: The Metallicity of the Pleiades
Authors: David R. Soderblom, Tanmoy Laskar, Jeff A. Valenti, John R. Stauffer, Luisa M. Rebull

We have measured the abundances of Fe, Si, Ni, Ti, and Na in 20 Pleiads with t_eff values near solar and with low v sin i using high-resolution, high signal-to-noise echelle spectra. We have validated our procedures by also analysing 10 field stars of a range of temperatures and metallicities that were observed by Valenti & Fischer (2005). Our result for the Pleiades is [Fe/H] = +0.03±0.02±0.05 (statistical and systematic). The average of published measurements for the Pleiades is +0.042±0.021.

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M45 - The Pleiades



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Blobrana


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They hang like a stray piece of tinsel in our Christmas sky, yet references to the Pleiades date from long before the Christian era. The cluster of stars is mentioned in the works of the early Greek poets Homer and Hesiod, from 700BC or before, and also in the Bible's book of Job, penned perhaps three centuries earlier. In fact, it seems that they play a role in the myths and folklore of many cultures around the world.
From some 30° high and due E at nightfall tonight, the cluster climbs to pass 60° high on the meridian at 22:00. Also called M45 from its entry in Messier's catalogue, its stars lie some 440 light years away and the brighter ones, identified on our image, stretch over 1° of sky (2 Moon-widths) in Taurus.

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