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Post Info TOPIC: Quintuplet Cluster
Blobrana


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IRAS 17430-2848
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Hubble Uncovering the Secrets of the Quintuplet Cluster

Although this cluster of stars gained its name due to its five brightest stars, it is home to hundreds more. The huge number of massive young stars in the cluster is clearly captured in this NASA/ESA Hubble Space Telescope image.
The cluster is located close to the Arches Cluster and is just 100 light-years from the center of our galaxy. The clusters proximity to the dust at the center of the galaxy means that much of its visible light is blocked, which helped to keep the cluster unknown until its discovery in 1990, when it was revealed by infrared observations. Infrared images of the cluster, like the one shown here, allow us to see through the obscuring dust to the hot stars in the cluster.
The Quintuplet Cluster hosts two extremely rare luminous blue variable stars: the Pistol Star and the lesser known V4650 Sgr.
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Blobrana


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RE: Quintuplet Cluster
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The Quintuplet cluster is a dense cluster of massive young stars near the Galactic Center (GC). Its name comes from the fact it has five prominent infrared sources residing in it.
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Title: The Quintuplet Cluster III. Hertzsprung-Russell diagram and cluster age
Authors: A. Liermann, W.-R. Hamann, L. M. Oskinova

The Quintuplet, one of three massive stellar clusters in the Galactic center, is located about 30pc in projection from Sagittarius A*. Based on near-infrared K-band spectra we determine temperatures and luminosities for all stars in our sample and construct the Herztsprung-Russell diagram. We find two distinct groups: early-type OB stars and late-type KM stars, well separated from each other. By comparison with Geneva stellar evolution models we derive initial masses exceeding 8 solar masses for the OB stars, that are located along an isochrone corresponding to a cluster age of about 4 million years. In addition, we derive number ratios (e. g. N_WR/N_O) and compare them with predictions of population synthesis models. We find that an instantaneous burst of star formation at about 3.3 to 3.6\,Myr ago is the most likely scenario to form the Quintuplet cluster. The late-type stars in the sample are red giant branch (RGB) stars or red supergiants (RSGs) according to their spectral signatures. It is discussed if they could physically belong to the Quintuplet cluster. Furthermore, we apply a mass-luminosity relation to construct the initial mass function (IMF) of the cluster. We find indications for a slightly top-heavy IMF.

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