J/AJ/147/138 Rotational and radial velocities of red giants (Carlberg, 2014)
Rotational and radial velocities of 1.3-2.2 M☉ red giants in open
clusters.
Carlberg J.K.
<Astron. J., 147, 138 (2014)>
=2014AJ....147..138C 2014AJ....147..138C
ADC_Keywords: Clusters, open ; Stars, giant ; Radial velocities ;
Rotational velocities
Keywords: open clusters and associations: general - stars: evolution -
stars: late-type - stars: rotation
Abstract:
This study presents the rotational distribution of red giant (RG)
stars in 11 old to intermediate age open clusters. The masses of these
stars are all above the Kraft break, so they lose negligible amounts
of their birth angular momentum (AM) during the main-sequence (MS)
evolution. However, they do span a mass range with quite different AM
distributions imparted during formation, with the stars less massive
than ∼1.6M☉ arriving on the MS with lower rotation rates than
the more massive stars. The majority of RGs in this study are slow
rotators across the entire red giant branch regardless of mass,
supporting the picture that intermediate-mass stars rapidly spin down
when they evolve off the MS and develop convection zones capable of
driving a magnetic dynamo. Nevertheless, a small fraction of RGs in
open clusters show some level of enhanced rotation, and faster
rotators are as common in these clusters as in the field RG
population. Most of these enhanced rotators appear to be red clump
stars, which is also true of the underlying stellar sample, while
others are clearly RGs that are above or below the clump. In addition
to rotational velocities, the radial velocities (RVs) and membership
probabilities of individual stars are also presented. Cluster
heliocentric RVs for NGC 6005 and Pismis 18 are reported for the first
time.
Description:
We compiled the open cluster sample by querying the WEBDA database
(http://www.univie.ac.at/webda/).
All of the stars listed in Table2 were observed over three runs with
two telescope-instrument combinations at Las Campanas Observatory in
2012. During three nights (beginning January 28-30) on the Irenee du
Pont telescope, all targets in M67 and NGC2477 were observed with the
echelle spectrograph. During two nights (beginning February 4 and 5)
on the Clay telescope, all stars in Collinder 110 and most of the
stars in Melotte 66 were observed with the Magellan Inamori Kyocera
Echelle (MIKE) spectrograph. Over another three nights (beginning May
7-9), the remaining stars in Mel66 and all of the stars in the
remaining clusters were observed with MIKE.
The detector for the du Pont echelle spectrograph is a SITe2K CCD with
24µ pixels. The instrument was set up with a 0.75" wide slit, which
yields a spectral resolving power
(Rλ=λ/Δλ) of 40000 and spans a wavelength
range of 3600-10100Å over 60 orders.
The MIKE spectrograph has both red and blue channels that can be used
independently. Although data were collected in both channels, only the
spectra from the red channel are used in this analysis. A slit width
of 0.5" was chosen to attain Rλ∼44000. The red data span a
wavelength range of 4800-9400Å over 34 orders.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 32 11 Studied open clusters
table2.dat 70 416 Observed red giant candidates
table5.dat 43 416 Radial and rotational velocities
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See also:
I/322 : UCAC4 Catalogue (Zacharias+, 2012)
J/MNRAS/430/221 : NGC 2849 and NGC 6134 UBVI photometry (Ahumada+, 2013)
J/AJ/145/134 : Velocities of 108 stars in Ruprecht 147 (Curtis+, 2013)
J/A+A/545/A139 : Radial Velocities of stars observed in M67 (Pasquini+, 2012)
J/ApJ/757/109 : Velocities + Li abundance in K giants (Carlberg+, 2012)
J/ApJ/732/39 : Rotational velocities of K giant stars (Carlberg+, 2011)
J/AJ/139/2034 : NGC 6253 stars equivalent widths (Anthony-Twarog+, 2010)
J/A+A/511/A56 : Abundances of five open clusters (Pancino+, 2010)
J/A+A/505/1129 : BVRIJHK and proper motions in NGC 6253 (Montalto+, 2009)
J/A+A/480/79 : Giants abundances in 5 Galactic clusters (Bragaglia+, 2008)
J/A+A/488/943 : Abundances of giants in 4 Galactic clusters (Sestito+, 2008)
J/A+A/485/303 : RVs for 1309 stars and 166 OCl (Mermilliod+, 2008)
J/AJ/135/209 : Velocities 761 HIP giants (Massarotti+, 2008)
J/A+A/475/1003 : Stellar parameters of G and K giant stars (Hekker+, 2007)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/A+A/423/189 : UBV and RV of red giants in NGC 2477 (Eigenbrod+, 2004)
J/MNRAS/309/739 : NGC 2660 UBVIc photometry (Sandrelli+, 1999)
J/AJ/115/1076 : UBRVI photometry of Collinder 110 (Dawson+, 1998)
J/A+AS/113/299 : Abundances and velocities for cluster giants (Minniti 1995)
J/AJ/106/181 : CCD photometry of open cluster M67 (Montgomery+ 1993)
http://www.univie.ac.at/webda/ : WEBDA database
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Cluster Open cluster name
14- 15 I2 h RAh Hour of Right Ascension (J2000) (1)
17- 20 F4.1 min RAm Minute of Right Ascension (J2000) (1)
22- 23 I2 s RAs ? Second of Right Ascension (J2000) (1)
25 A1 --- DE- Sign of the Declination (J2000) (1)
26- 27 I2 deg DEd Degree of Declination (J2000) (1)
29- 32 F4.1 arcmin DEm Arcminute of Declination (J2000) (1)
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Note (1): From SIMBAD database (http://simbad.u-strasbg.fr/simbad/).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Cluster Open cluster name (G1)
14- 17 I4 --- Star Star number within the cluster
19- 20 I2 h RAh Hour of Right Ascension (J2000)
22- 23 I2 min RAm Minute of Right Ascension (J2000)
25- 29 F5.2 s RAs Second of Right Ascension (J2000)
31 A1 --- DE- Sign of the Declination (J2000)
32- 33 I2 deg DEd Degree of Declination (J2000)
35- 36 I2 arcmin DEm Arcminute of Declination (J2000)
38- 42 F5.2 arcsec DEs Arcsecond of Declination (J2000)
44- 47 F4.1 mag Vmag The V band magnitude
49- 58 A10 "Y:M:D" Date UT date of the observation
60- 62 I3 s Exp Exposure time
64- 70 A7 --- Inst Instrument used (1)
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Note (1): Instruments are:
echelle = echelle spectrograph on du Pont telescope;
MIKE = Magellan Inamori Kyocera Echelle (MIKE) spectrograph on the Clay
telescope.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Cluster Open cluster name (G1)
14- 17 I4 --- Star Star number within the cluster
19- 23 F5.1 km/s HRV Heliocentric radial velocity
25- 28 F4.1 km/s e_HRV Uncertainty in HRV
30- 34 F5.1 --- o_HRV Δ/σv used to gauge cluster
membership (2)
36- 39 F4.1 km/s vsini Projected rotational velocity
41- 43 F3.1 km/s e_vsini Uncertainty in vsini (3)
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Note (2): Number of σ stellar HRV is from cluster HRV. Δ is the
absolute difference between the stellar HRV and the mean cluster HRV. The
dispersion of the Gaussian (σv) is a measure of the intrinsic
velocity dispersion within the cluster.
Note (3): A value of "0." indicates that the vsini is a lower limit.
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Global notes:
Note (G1): Our open cluster sample is: Collinder110, M67, Melotte66, NGC2477,
NGC2506, NGC2660, NGC6005, NGC6134, NGC6253, Pismis18, and Ruprecht147.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 30-Sep-2014