The binary fraction and mass segregation in Alpha Persei open cluster

Sheikhi, Najmeh, Hasheminia, Maryam, Khalaj, Pouria, Haghi, Hosein, Zonoozi, Akram H. and Baumgardt, Holger (2016) The binary fraction and mass segregation in Alpha Persei open cluster. Monthly Notices of the Royal Astronomical Society, 457 1: 1028-1036. doi:10.1093/mnras/stw059

Author Sheikhi, Najmeh
Hasheminia, Maryam
Khalaj, Pouria
Haghi, Hosein
Zonoozi, Akram H.
Baumgardt, Holger
Title The binary fraction and mass segregation in Alpha Persei open cluster
Journal name Monthly Notices of the Royal Astronomical Society   Check publisher's open access policy
ISSN 1365-2966
Publication date 2016-03-21
Year available 2016
Sub-type Article (original research)
DOI 10.1093/mnras/stw059
Open Access Status Not Open Access
Volume 457
Issue 1
Start page 1028
End page 1036
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Collection year 2017
Language eng
Formatted abstract
We have obtained membership probabilities of stars within a field of ∼3 from the centre of the open cluster Alpha Persei using proper motions and photometry from the PPMXL and Wide-field Infrared Survey Explorer catalogues. We have identified 810 possible stellar members of Alpha Persei. We derived the global and radial present-day mass function (MF) of the cluster and found that they are well matched by two-stage power-law relations with different slopes at different radii. The global MF of Alpha Persei shows a turnover at m = 0.62 M with low- and high-mass slopes of αlow = 0.50 ± 0.09 (0.1 < m/ M < 0.62) and αhigh = 2.32 ± 0.14 (0.62 ≤ m/ M < 4.68), respectively. The high-mass slope of the cluster increases from 2.01 inside 1.10 to 2.63 outside 2∘.2, whereas the mean stellar mass decreases from 0.95 to 0.57 M in the same regions, signifying clear evidence of mass segregation in the cluster. From an examination of the high-quality colour–magnitude data of the cluster and performing a series of Monte Carlo simulations, we obtained a binary fraction of fbin = 34 ± 12 per cent for stars with 0.70 < m/ M < 4.68. This is significantly larger than the observed binary fraction, indicating that this open cluster contains a large population of unresolved binaries. Finally, we corrected the MF slopes for the effect of unresolved binaries and found low- and high-mass slopes of αlow = 0.89 ± 0.11 and αhigh = 2.37 ± 0.09 and a total cluster mass of 352 M for Alpha Persei.
Keyword Binaries: general
Stars: luminosity function
Stars: mass function
Open clusters and associations: individual: Alpha Per
Infrared: stars
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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