J/ApJ/797/43 Blue stragglers in ω Cen (Mucciarelli+, 2014)
Spinning like a blue straggler: the population of fast rotating blue straggler
stars in ω Centauri.
Mucciarelli A., Lovisi L., Ferraro F.R., Dalessandro E., Lanzoni B.,
Monaco L.
<Astrophys. J., 797, 43 (2014)>
=2014ApJ...797...43M 2014ApJ...797...43M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Radial velocities ;
Keywords: blue stragglers - globular clusters: individual (NGC 5139) -
techniques: spectroscopic
Abstract:
By using high-resolution spectra acquired with FLAMES-GIRAFFE at the
ESO/VLT, we measured the radial and rotational velocities for 110 blue
straggler stars (BSSs) in ω Centauri, the globular cluster-like
stellar system harboring the largest known BSS population. According
to their radial velocities, 109 BSSs are members of the system. The
rotational velocity distribution is very broad, with the bulk of BSSs
spinning at less than ∼40 km/s (in agreement with the majority of such
stars observed in other globular clusters) and a long tail reaching
∼200km/s. About 40% of the sample has vesini>40km/s and about 20%
has vesini>70km/s. Such a large fraction is very similar to the
percentage of fast rotating BSSs observed in M4. Thus, ω
Centauri is the second stellar cluster, beyond M4, with a surprisingly
high population of fast spinning BSSs. We found a hint of radial
behavior for a fraction of fast rotating BSSs, with a mild peak within
one core radius, and a possible rise in the external regions (beyond
four core radii). This may suggest that recent formation episodes of
mass transfer BSSs occurred preferentially in the outskirts of ω
Centauri, or that braking mechanisms able to slow down these stars are
least efficient in the lowest density environments.
Description:
The spectroscopic data set analyzed in this paper includes two samples
of high-resolution spectra acquired with the multi-object spectrograph
FLAMES-GIRAFFE mounted at the Very Large Telescope of the European
Southern Observatory (ESO).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 109 Parameters and velocities of the observed BSS sample
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See also:
J/A+A/324/915 : Blue stragglers in M3 (Ferraro+ 1997)
J/AJ/114/1087 : Omega Cen radial velocities (Mayor+ 1997)
J/A+A/424/1101 : Variable Stars in the field of ω Cen (Kaluzny+, 2004)
J/ApJ/632/894 : BSS, HB and turnoff stars in 4 GC (De Marco+, 2005)
J/ApJ/663/267 : Blue straggler population of M5 (Lanzoni+, 2007)
J/ApJ/661/L155 : Radial velocities RGB stars in omega Cen (Pancino+, 2007)
J/ApJ/677/1069 : Blue stragglers in NGC 6388 (Dalessandro+, 2008)
J/ApJ/681/311 : Blue stragglers in NGC 2419 (Dalessandro+, 2008)
J/ApJ/704/750 : Rotational behavior of metal-poor stars (Cortes+, 2009)
J/MNRAS/396/2183 : Radial vel. of red giants in ω Cen (Sollima+ 2009)
J/ApJ/710/1032 : Proper motions in ω Cen (Anderson+, 2010)
J/ApJ/722/1373 : ω Centauri giants abundances (Johnson+, 2010)
J/A+A/519/L3 : Lithium content of ω Cen (Monaco+, 2010)
J/ApJ/726/L20 : Spectroscopy of Terzan 5 (Origlia+, 2011)
J/ApJ/754/91 : Abundances and velocities of NGC 6397 stars (Lovisi+, 2012)
J/ApJ/772/148 : Blue straggler and red giant stars in M30 (Lovisi+, 2013)
J/A+A/560/A29 : O-stars in the VFTS Survey (Ramirez-Agudelo+ 2013)
Byte-by-byte Description of file:table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID [6365/711338] Identification number
8- 18 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 30 F11.7 deg DEdeg Declination in decimal degrees (J2000)
32- 36 I5 K Teff [7115/10703] Effective temperature
38- 41 F4.2 [cm/s2] logg [3.77/4.59] Log of the surface gravity
43- 47 F5.1 km/s RV [191.3/266.1] Radial velocity
49- 51 I3 km/s vsini [0/200] Projected rotational velocity
53- 55 A3 --- Data Dataset identifier (1)
57- 61 A5 --- OName Other name (2)
63- 69 A7 --- VarType Variable type (3)
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Note (1): Dataset identifier, defined as follows:
1 = 73 BSSs observed with the gratings
HR5A (R∼18,500, Δλ=4340-4587Å),
HR14A (R∼18,000, Δλ=6308-6701Å), and
HR15N (R∼17,000, Δλ=6470-6790Å)
during the ESO periods 81 and 89 (PI: Ferraro)
2 = 54 BSSs observed with the gratings
HR2 (R∼19,600, Δλ=3854-4049Å) and
HR4 (R∼20,350, Δλ=4340-4587Å)
and retrieved from the ESO Archive (ESO period 77, PI: Freyhammer).
A total of 17 BSSs are in common between the two data sets.
See details in Section 2 for further details.
Note (2): The observed BSSs with the corresponding name in the catalogs by
Kaluzny et al. (2004, J/A+A/424/1101) and Olech et al.
(2005MNRAS.363...40O 2005MNRAS.363...40O). Use <Cl* NGC 5139 Saw VNNN> in SIMBAD.
Note (3): Variable type, from Kaluzny et al. (2004, J/A+A/424/1101) and Olech
et al. (2005MNRAS.363...40O 2005MNRAS.363...40O), defined as follows:
SX = SX Phe
WUMa = W UMa
EA = detached eclipsing binary
ell? = candidate ellipsoidal variable
P=3.3d = variable star with a period of ∼3.3 days
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History:
From electronic version of the journal
(End) Prepared by [AAS], Marianne Brouty [CDS] 16-Nov-2016