J/A+A/618/A2 Quintuplet cluster updated stellar census (Clark+, 2018)
An updated stellar census of the Quintuplet cluster.
Clark J.S., Lohr M.E., Patrick L.R., Najarro F., Dong H., Figer D.F.
<Astron. Astrophys., 618, A2 (2018)>
=2018A&A...618A...2C 2018A&A...618A...2C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open
Keywords: stars: early-type - stars: Wolf-Rayet - stars: evolution -
stars: massive - stars: emission-line, Be -
open clusters and associations: individual: Quintuplet cluster
Abstract:
Found within the central molecular zone, the Quintuplet is one of the
most massive young clusters in the Galaxy. As a consequence it offers
the prospect of constraining stellar formation and evolution in
extreme environments. However, current observations suggest that it
comprises a remarkably diverse stellar population that is difficult to
reconcile with an instantaneous formation event.
To better understand the nature of the cluster our aim is to improve
observational constraints on the constituent stars.
In order to accomplish this goal we present Hubble Space
Telescope/NICMOS+WFC3 photometry and Very Large Telescope/SINFONI+KMOS
spectroscopy for ∼100 and 71 cluster members, respectively.
Spectroscopy of the cluster members reveals the Quintuplet to be far
more homogeneous than previously expected. All supergiants are
classified as either O7-8 Ia or O9-B0 Ia, with only one object of
earlier (O5 I-III) spectral type. These stars form a smooth
morphological sequence with a cohort of seven early-B hypergiants and
six luminous blue variables and WN9-11h stars, which comprise the
richest population of such stars of any stellar aggregate known. In
parallel, we identify a smaller population of late-O hypergiants and
spectroscopically similar WN8-9ha stars. No further H-free Wolf-Rayet
(WR) stars are identified, leaving an unexpectedly extreme ratio of
13:1 for WC/WN stars. A subset of the O9-B0 supergiants are
unexpectedly faint, suggesting they are both less massive and older
than the greater cluster population. Finally, no main sequence objects
were identifiable.
Due to uncertainties over which extinction law to apply, it was not
possible to quantitatively determine a cluster age via isochrone
fitting. Nevertheless, we find an impressive coincidence between the
properties of cluster members preceding the H-free WR phase and the
evolutionary predictions for a single, non-rotating 60M☉ star;
in turn this implies an age of ∼3.0-3.6Myr for the Quintuplet. Neither
the late O-hypergiants nor the low luminosity supergiants are
predicted by such a path; we suggest that the former either result
from rapid rotators or are the products of binary driven
mass-stripping, while the latter may be interlopers. The H-free WRs
must evolve from stars with an initial mass in excess of 60M☉
but it appears difficult to reconcile their observational properties
with theoretical expectations. This is important since one would
expect the most massive stars within the Quintuplet to be undergoing
core-collapse/SNe at this time; since the WRs represent an
evolutionary phase directly preceding this event,their physical
properties are crucial to understanding both this process and the
nature of the resultant relativistic remnant. As such, the Quintuplet
provides unique observational constraints on the evolution and death
of the most massive stars forming in the local, high metallicity
Universe.
Description:
This paper reports the results of a combined photometric
(HST/NICMOS+WFC3) and spectroscopic study of the Quintuplet cluster,
the latter comprising both archival (VLT/SINFONI) and new (VLT/KMOS)
data. Photometry is supplied for 108 objects derived from the combined
target lists of Figer at al. (1999ApJ...514..202F 1999ApJ...514..202F) and Liermann et
al., 2009, Cat. J/A+A/494/1137) and from which stars of late spectral
type have been excluded. We present new spectra of 63 unique objects
for which our re-reduction of the VLT/SINFONI data has resulted in a
much improved S/N, permitting reliable assessment of faint
classification diagnostics such as HeII 2.189um and CIV 2.079um. These
are supplemented by lower S/N and resolution published data for a
further eight stars, yielding a final spectroscopic dataset of 71
stars. Analysis of these data results in the re-classification of
∼70% of the cluster members.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 101 108 HST photometry of stellar members of the
Quintuplet cluster
tablea2.dat 112 71 Stellar population of the Quintuplet cluster
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See also:
J/MNRAS/371/38 : X-ray observations of Arches & Quintuplet (Wang+, 2006)
J/A+A/494/1137 : Quintuplet cluster K-band spectral catalog (Liermann+, 2009)
J/A+A/540/A57 : Mass function of Quintuplet cluster (Hussmann+, 2012)
J/ApJ/789/115 : The Quintuplet cluster astrometry & photometry (Stolte+, 2014)
J/A+A/578/A4 : Photometry and motions in Arches & Quintuplet (Stolte+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- ID qF number or other name (1)
13- 15 I3 --- LHO ?=- LHO number
17- 25 F9.5 deg RAdeg Right ascension (J2000)
27- 35 F9.5 deg DEdeg Declination (J2000)
37- 41 F5.2 mag F110W ?=- HST F110W magnitude
43- 46 F4.2 mag e_F110W ? rms uncertainty on F110W
47 A1 --- n_F110W [*] Uncertainty flag on F110W
48- 52 F5.2 mag F160W ?=- HST F160W magnitude
54- 57 F4.2 mag e_F160W ? rms uncertainty on F160W
58 A1 --- n_F160W [*] Uncertainty flag on F160W
59- 63 F5.2 mag F205W ?=- HST F205W magnitude
65- 68 F4.2 mag e_F205W ? rms uncertainty on F205W
69 A1 --- n_F205W [*] Uncertainty flag on F205W
70- 74 F5.2 mag F127M ?=- HST F127M magnitude
76- 79 F4.2 mag e_F127M ? rms uncertainty on F127M
81- 85 F5.2 mag F139M ?=- HST F139M magnitude
87- 90 F4.2 mag e_F139M ? rms uncertainty on F139M
92- 96 F5.2 mag F153M ?=- HST F153M magnitude
98-101 F4.2 mag e_F153M ? rms uncertainty on F153M
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Note (1): Objects for which no photometry is available are
qF76 (WC9; this work),
qF269 (OB I; Figer at al., 1999ApJ...514..202F 1999ApJ...514..202F),
qF301 (< OB I; Figer at al., 1999ApJ...514..202F 1999ApJ...514..202F),
qF311 (B1-3 I; Figer at al., 1999ApJ...514..202F 1999ApJ...514..202F),
qF362 (LBV; Geballe et al., 2000ApJ...530L..97G 2000ApJ...530L..97G),
LHO23 (O3-6 I-II; Liermann et al., 2009, Cat. J/A+A/494/1137),
LHO70 (O7-8 If; Liermann et al., 2009, Cat. J/A+A/494/1137) and
G0.120-0.048 (LBV; Mauerhan et al. 2010ApJ...710..706M 2010ApJ...710..706M).
qF353E, qF381 and qF406 were outside the NICMOS field-of-view and hence lack
F110W, F160W and F205W magnitudes.
The following sources had multiple counterparts within 2.5 pixels of their
position in the NICMOS data;
qF276 (two sources with one 2.5mag fainter; brighter selected),
LHO15 (two sources with a difference of 0.3m; closest selected),
LHO64 (two sources with one 3.4mag fainter; brighter selected),
LHO72 (two sources with one 1.2mag fainter; closest selected) and
LHO73 (two sources within one pixel with broadly comparable magnitudes;
closest selected).
Caution should therefore be applied regarding the F110W, F160W and F205W
magnitudes for LHO15, LHO72 and LHO73; these are followed by an *.
Finally no NICMOS counterpart to LHO139 was found within 9 pixels of the
anticipated position.
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- ID qF number or other name (G1)
13- 15 I3 --- LHO ? LHO number (G2)
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 28 F5.2 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 40 F4.1 arcsec DEs Declination (J2000)
42- 57 A16 --- ClassC Most up-to-date spectral classification
available from either Figer at al.
(1999ApJ...514..202F 1999ApJ...514..202F) or Liermann et al.,
2009, Cat. J/A+A/494/1137)
59- 72 A14 --- ClassR Revised classification, this paper
74-112 A39 --- Notes Notes (1)
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Note (1): additional widely used identifiers (e.g. WR number and the naming
convention of Dong et al., 2011, Cat. J/MNRAS/417/114).
qF309 and qF344 are re-classified via comparison of the spectra from
Figer at al. (1999ApJ...514..202F 1999ApJ...514..202F) and Mauerhan et al. (2010ApJ...710..706M 2010ApJ...710..706M)
to our new data.
The five Quintuplet proper members are those stars with MGM 5-# identifiers
(Moneti et al. 1992MNRAS.258..705M 1992MNRAS.258..705M).
QX# and QR# indicate radio and X-ray detections reported in Lang et al.
(2005AJ....130.2185L 2005AJ....130.2185L) and Wang et al. (2006MNRAS.371...38W 2006MNRAS.371...38W) respectively.
The Pistol star is also reported as a radio source but no new identifier is
assigned for it, while the X-ray designation of qF344 derives from Muno et al.
(2009, Cat. J/ApJS/181/110).
Tuthill et al. (2006Sci...313..935T 2006Sci...313..935T) provide the orbital period for qF211 and
suggest periods in the hundreds of days for qF243, qF251, and qF258 based on
the size of their dusty nebulae.
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Global notes:
Note (G1): qF NNNa from Figer at al., 1999ApJ...514..202F 1999ApJ...514..202F, qF NNNW in Simbad.
Note (G2): From Liermann et al., 2009, Cat. J/A+A/494/1137, LHO NNN in Simbad.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Nov-2018