Dr. Peter Frinchaboy (TCU) Why star clusters? Open cluster - 100s - - PowerPoint PPT Presentation

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Oct 01, 2023 583 likes •789 views

Kelly Jackson (Senior - TCU) Dr. Peter Frinchaboy (TCU) Why star clusters? Open cluster - 100s to 1000s of stars that formed at the same time from the same cloud of interstellar gas and dust Stars have the same properties: age, distance

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Kelly Jackson (Senior - TCU)

Dr. Peter Frinchaboy (TCU)

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Why star clusters?

 Open cluster - 100s to 1000s

f stars that formed at the

same time from the same cloud of interstellar gas and dust

 Stars have the same properties: age, distance

from us, metallicity, and extinction value

 Extinction – dimming of starlight due to dust in ISM  Star clusters are useful for studying stellar

evolution and the cluster’s surrounding galaxy (e.g. the Milky Way)

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 Utilizing near to mid-infrared data collected from:

 Two Micron All-Sky Survey (2MASS)  Spitzer Space Telescope/

GLIMPSE-I, II, 3D, & 360 surveys

 Wide-Field Infrared Survey

Explorer (WISE)

1.6 m 2.1 m 2.2 m 3.6 m 4.5 m

2MASS GLIMPSE

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 Areas within the Milky Way that have

been covered by GLIMPSE surveys:

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How to Isolate a Cluster

 Obtain extinction (AK) values for each star

in a cluster

 Raleigh Jeans Color Excess Method

(Majewski, Zasowski, & Nidever 2011)

 Isolate area twice the cluster radius and

compare stars within the cluster radius to

uter “field stars”.

 Windows a range of AK and step through

the AK values.

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 Compare normalized ratio of stars

within cluster radius to background at each step through AK values

 Identify overdensity in AK space

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Application to

 APOGEE - large-scale spectroscopic survey

f Galactic stars.

 H-band (1.5-1.7μm), R ~ 25,000, σRV ~ 300 m/s.  100,000 stars, S/N = 100/pixel, 15 elements/star.

 Will utilize star clusters in order to explore

Galactic evolution

 Can directly link age and chemistry

 Isolated cluster members (especially red-

giants) in targeted fields are submitted as high-priority targets.

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Future Work

 Complications arise from wide range of

cluster sizes and distances

 Problematic small, distant clusters and large,

nearby clusters

 Need to determine what parameters

work best for the majority of clusters

 Soon will utilize more WISE fields and

UKIDSS to get deeper data

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