J/ApJ/921/117 43yr spectrosc. monitoring of the Pleiades region (Torres+, 2021)
Long-term spectroscopic survey of the Pleiades cluster: the binary population.
Torres G., Latham D.W., Quinn S.N.
<Astrophys. J., 921, 117 (2021)>
=2021ApJ...921..117T 2021ApJ...921..117T
ADC_Keywords: Clusters, open; Spectra, optical; Binaries, spectroscopic;
Radial velocities; Rotational velocities; Effective temperatures
Keywords: Open star clusters ; Binary stars ; Spectroscopic binary stars ;
Radial velocity ; Spectroscopy
Abstract:
We present the results of a spectroscopic monitoring program of the
Pleiades region aimed at completing the census of spectroscopic
binaries in the cluster, extending it to longer periods than
previously reachable. We gathered 6104 spectra of 377 stars between
1981 and 2021, and merged our radial velocities with 1151 measurements
from an independent survey by others started three years earlier. With
the combined data spanning more than 43yr, we have determined orbits
for some 30 new binary and multiple systems, more than doubling the
number previously known in the Pleiades. The longest period is 36.5yr.
A dozen additional objects display long-term trends in their
velocities, implying even longer periods. We examine the collection of
orbital elements for cluster members, and find that the shape of the
incompleteness-corrected distribution of periods (up to 104 days) is
similar to that of solar-type binaries in the field, while that of the
eccentricities is different. The mass-ratio distribution is consistent
with being flat. The binary frequency in the Pleiades for periods up
to 104 days is 25%±3% after corrections for undetected binaries,
which is nearly double that of the field up to the same period. The
total binary frequency including known astrometric binaries is at
least 57%. We estimate the internal radial velocity dispersion in the
cluster to be 0.48±0.04km/s. We revisit the determination of the
tidal circularization period, and confirm its value to be 7.2±1.0d,
with an improved precision compared to an earlier estimate.
Description:
Spectroscopic monitoring of the Pleiades region at the Center for
Astrophysics (CfA) began in December of 1981, and was carried out with
four instrument/telescope combinations. From that initial date until
February of 2009, spectra were gathered with three nearly identical
copies of the Digital Speedometer. They were attached to the 1.5m
Tillinghast reflector at the Fred L. Whipple Observatory on Mount
Hopkins (AZ), the now-closed 1.5m Wyeth reflector at the Oak Ridge
Observatory (MA), and the 4.5m equivalent MMT also on Mount Hopkins,
before its conversion to a monolithic 6.5m telescope. The Digital
Speedometers had a resolving power of R∼35000.
Beginning in October of 2009, further observations were collected with
the Tillinghast Reflector Echelle Spectrograph (TRES) on the 1.5m
Tillinghast reflector. This is a modern, bench-mounted, fiber-fed
spectrograph delivering a resolving power of R∼44000, with a CCD
detector that records 51 echelle orders between 3800-9100Å. We
gathered 3663 spectra with this instrument through the end of the
2020/2021 observing season.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 118 377 List of objects in the Pleiades region observed
spectroscopically at the Center for
Astrophysics (CfA)
table2.dat 57 4631 CfA radial velocity measurements for single-lined
objects
table3.dat 70 932 CfA radial velocity measurements for double-lined
objects
table4.dat 80 377 Radial velocity statistics for objects in the
Pleiades region observed spectroscopically at
the CfA
table5.dat 64 377 Effective temperatures and projected rotational
velocities
table9.dat 49 72 Radial velocity measurements for the triple-lined
system HII 1338
table10.dat 37 40 Radial velocity measurements for the double-lined
triple system HII 2027
table14.dat 61 75 Astrometric companions to our target stars
notes.dat 2044 106 Notes on individual objects (Appendix A)
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2020)
II/131 : Tonantzintla Pleiades Flare Stars (Haro+ 1982)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
III/279 : RAVE 5th data release (Kunder+, 2017)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/AJ/106/637 : ICCD speckle observations. IX (Mason+, 1993)
J/ApJS/85/315 : F, G and K dwarf stars of the Pleiades (Soderblom+ 1993)
J/A+A/299/696 : Pleiades field Membership prob. (Schilbach+, 1995)
J/A+A/323/139 : K magnitude of Pleiades low-mass binaries (Bouvier+ 1997)
J/A+A/320/74 : Radial velocities of Pleiades members (Mermilliod+ 1997)
J/A+A/332/575 : Pleiades member list (Belikov+ 1998)
J/A+A/335/183 : Pleiades low-mass stars rot. velocities (Queloz+ 1998)
J/A+A/329/101 : Masses of Pleiades members (Raboud+ 1998)
J/AJ/124/1144 : Orbits of 171 single-lined sp. binaries (Latham, 2002)
J/A+A/463/579 : Geneva photometry of HD 23642 (Groenewegen+, 2007)
J/ApJS/172/663 : Infrared observations of the Pleiades (Stauffer+, 2007)
J/AJ/133/2524 : Spectra of young nearby stars (White+, 2007)
J/A+A/485/95 : Velocities of F-G-K stars in Blanco 1 (Mermilliod+, 2008)
J/AJ/138/159 : NGC 6819 stellar radial-velocity & phot. (Hole+, 2009)
J/AJ/137/3358 : Speckle interferometry of massive stars (Mason+, 2009)
J/A+A/498/949 : Vel. of F-K dwarfs in open clusters (Mermilliod+, 2009)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/A+A/546/A69 : Orbits of visual bin. & dynamical masses (Malkov+, 2012)
J/AJ/148/30 : BVI photometry of 350 Pleiades stars (Kamai+, 2014)
J/AJ/148/38 : WIYN open cluster study. LX. NGC 6819 (Milliman+, 2014)
J/A+A/577/A148 : The Seven Sisters DANCe. I. Pleiades (Bouy+, 2015)
J/AJ/150/97 : Radial velocities in M67. I. Members (Geller+, 2015)
J/AJ/150/10 : WOCS. LXVI. Radial velocity survey in M35 (Leiner+, 2015)
J/PASJ/68/92 : NIR obs. of Pleiades stars in SEEDS (Konishi+, 2016)
J/A+A/585/A150 : On the metallicity of open clusters. III. (Netopil+, 2016)
J/AJ/152/114 : Pleiades members with K2 LCs. II. (Rebull+, 2016)
J/AJ/152/113 : Pleiades members with K2 LCs. I. Periods (Rebull+, 2016)
J/A+A/601/A19 : Gaia DR1 open cluster members (Gaia Collaboration+, 2017)
J/A+A/598/A48 : Parallaxes for 1146 Pleiades stars (Galli+, 2017)
J/A+A/607/A124 : K-G-F dwarfs stellar granulation var. (Meunier+, 2017)
J/MNRAS/470/3937 : Open clusters multimembership catalog (Sampedro+, 2017)
J/A+A/616/A10 : Open clusters GaiaDR2 HR diag. (Gaia Collaboration, 2018)
J/AJ/155/51 : Robo-AO bin. stars in 3 open clusters (Hillenbrand+, 2018)
J/AJ/155/39 : Variability of TIC sources with KELT (Oelkers+, 2018)
J/A+A/617/A15 : Membership prob. of Pleiades objects (Olivares+, 2018)
J/AJ/157/196 : Close companions around young stars (Kounkel+, 2019)
J/AJ/160/169 : WOCS. LXXXII. Orbits & RVs in NGC 7789 (Nine+, 2020)
J/ApJ/901/91 : Sp. obs. of rapidly rot. stars in Pleiades (Torres, 2020)
J/AJ/161/190 : RVels of binary population in M67 (Geller+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/377] Running sequence number
5- 27 A23 --- Name Source name
29- 36 F8.5 deg RAdeg [51.8/61] Right Ascension (ICRS) at Ep=2016.0
38- 46 F9.5 deg DEdeg [19/28.3] Declination (ICRS) at Ep=2016.0
48- 65 I18 --- Gaia Gaia EDR3 catalog identifier
67- 71 F5.2 mag Gmag [3.7/15.02] Gaia EDR3 catalog G band magnitude
73- 78 F6.3 mas plx [0.1/24.1]? Gaia EDR3 catalog parallax
80- 84 F5.3 mas e_plx [0.013/0.6]? Uncertainty in plx
86- 93 F8.3 mas/yr pmRA [-6.4/152]? Gaia EDR3 catalog proper motion
in RA*cos(DE)
95- 99 F5.3 mas/yr e_pmRA [0.015/0.8]? Uncertainty in pmRA
101-107 F7.3 mas/yr pmDE [-61/-1]? Gaia EDR3 catalog proper motion in DE
109-113 F5.3 mas/yr e_pmDE [0.01/0.5]? Uncertainty in pmDE
115-118 A4 --- Mm Member code(s) (1)
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Note (1): Member codes as follows:
NM = objects that are not considered members of the cluster (see Section 2.1);
68 occurrences and 4 "NM?".
b = Early-type stars with spectroscopic results reported previously
(Torres 2020, J/ApJ/901/91 ; 33 occurrences).
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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- 3 I3 --- Seq [2/377] Internal index number
5- 27 A23 --- Name Source name (1)
29- 38 F10.4 d HJD [44957.5/59299.7] Heliocentric Julian Date
HJD-2400000
40- 45 F6.2 km/s RVel [-65/81] Heliocentric radial velocity (G1)
47- 51 F5.2 km/s e_RVel [0.06/22] Uncertainty in RVel
53- 55 I3 --- S/N [1/496] Signal-to-Noise ratio per
resolution element
57 I1 --- Inst [1/2] Instrument code (G2)
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Note (1): HII 2147 and rapidly-rotating early type stars are not included, as
their velocities have been published separately by
Torres+ (2020ApJ...898....2T 2020ApJ...898....2T) and Torres (2020, J/ApJ/901/91),
respectively.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/366] Internal index number
5- 27 A23 --- Name Source name
29- 38 F10.4 d HJD [44958.6/59298.7] Heliocentric Julian Date
HJD-2400000
40- 45 F6.2 km/s RVel1 [-94/107]? Primary Heliocentric radial velocity (G1)
47- 50 F4.2 km/s e_RVel1 [0.06/4]? Uncertainty in RVel1
52- 58 F7.2 km/s RVel2 [-140/151]? Secondary Heliocentric radial
velocity (G1)
60- 64 F5.2 km/s e_RVel2 [0.14/19]? Uncertainty in RVel2
66- 68 I3 --- S/N [7/248] Signal-to-Noise ratio per resolution element
70- 70 I1 --- Inst [1/2] Instrument code (G2)
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/377] Internal index number
4- 4 A1 --- f_Seq [*] *=a note of interest is given
(see notes.dat file)
6- 28 A23 --- Name Source name
30- 34 I5 d Span [0/15487] CfA observation time span
36- 37 I2 --- NDS [0/78] Number of Digital Speedometers RVel
measurements
39- 40 I2 --- NTRES [0/65] Number of TRES RVel measurements
42- 43 I2 --- NCOR [0/37] Number of CORAVEL RVel measurements
45- 50 F6.2 km/s RVel [-61/81] Weighted mean radial velocity (2)
52- 56 F5.2 km/s e_RVel [0.1/13] Uncertainty in RVel
58- 64 F7.5 --- Pchi2 [0/1]? χ2 probability of velocity
variability
66- 72 F7.3 --- e/i [0.009/109]? The e/i metric
74- 80 A7 --- Flag Flag code (3)
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Note (2): Including the CORAVEL measurements when available.
Note (3): The Flag column indicates non-members ("NM"), and known binaries
with spectroscopic orbits ("SB1", "SB2", "SB3"), astrometric orbits
("AST"), or long-term trends ("L"), as reported in Sections 5, 6, and
7. Early-type stars with spectroscopic results published previously
(Torres 2020, J/ApJ/901/91), are included for completeness, and are
flagged with a "b".
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/377] Internal index number
5- 27 A23 --- Name Source name
29 A1 --- f_Name Flag on name (4)
31- 35 I5 K Teff1 [3500/12250]? Primary effective temperature
36 A1 --- f_Teff1 [*] *: Teff1 adopted based on external information
38- 40 I3 K e_Teff1 [100/500]? Uncertainty in Teff1
42- 44 I3 km/s vsini1 [0/317]? Primary projected rotational velocity (5)
45 A1 --- f_vsini1 [*] *: vsini1 adopted based on external information
47- 48 I2 km/s e_vsini1 [1/25]? Uncertainty in vsini1
50- 53 I4 K Teff2 [3400/7700]? Secondary effective temperature
54 A1 --- f_Teff2 [*] *: Teff2 adopted based on external information
56- 58 I3 K e_Teff2 [100/600]? Uncertainty in Teff2
60- 61 I2 km/s vsini2 [0/35]? Secondary projected rotational velocity (5)
62 A1 --- f_vsini2 [*] *: vsini2 adopted based on external information
64 I1 km/s e_vsini2 [2/4]? Uncertainty in vsini2
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Note (4): Flag as follows:
a= Tertiary parameters adopted for HII 1338 are Teff=5250K and vsini=0km/s.
b= The temperature determination for the Am secondary of HII 1431
used [Fe/H]=+0.5.
c= Parameters for the secondary of HII 2147 are from
Torres+ (2020ApJ...898....2T 2020ApJ...898....2T/).
Note (5): Rotational velocities for rapidly-rotating early type stars are
reproduced from the work of Torres (2020, J/ApJ/901/91).
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d HJD [51920.6/54485.7] Heliocentric Julian Date
HJD-2400000
12- 17 F6.2 km/s RVel1 [-57/65] Primary Heliocentric radial velocity (G1)
19- 22 F4.2 km/s e_RVel1 [1/4] Uncertainty in RVel1
24- 29 F6.2 km/s RVel2 [-63/68] Secondary Heliocentric radial velocity (G1)
31- 34 F4.2 km/s e_RVel2 [1.4/4] Uncertainty in RVel2
36- 39 F4.1 km/s RVel3 [-9/25] Tertiary Heliocentric radial velocity (G1)
41- 44 F4.1 km/s e_RVel3 [6/18] Uncertainty in RVel3
46- 47 I2 --- S/N [16/46] Signal-to-Noise ratio per resolution element
49 I1 --- Inst [1] Instrument code (G2)
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d HJD [45302.8/59231.7] Heliocentric Julian Date
HJD-2400000
12- 16 F5.2 km/s RVelA [-0.8/10.1] Primary Heliocentric radial
velocity (G1)
18- 21 F4.2 km/s e_RVelA [0.3/1.4] Uncertainty in RVelA
23- 27 F5.2 km/s RVelBa [-10/31] Ba component Heliocentric radial
velocity (G1)
29- 32 F4.2 km/s e_RVelBa [0.25/2] Uncertainty in RVelBa
34- 35 I2 --- S/N [9/42] Signal-to-Noise ratio per resolution
element
37 I1 --- Inst [1/2] Instrument code (G2)
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Byte-by-byte Description of file: table14.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [7/369] Internal index number
4 A1 --- f_Seq [*] *=note of interest is given
(see notes.dat file)
6- 15 A10 --- Name Source name
17- 26 A10 --- WDS Washington Double Star catalog identifier
28- 40 A13 --- Disc WDS Discoverer code and component designation
42- 47 F6.3 arcsec Sep [0.002/17.5] Most recent angular separation
49- 52 F4.2 mag dmag1 [0/9.8]? Magnitude difference in Filt1
53 A1 --- u_dmag1 [:] Uncertainty flag on dmag1
54 A1 --- Filt1 Filter used in dmag1
56- 59 F4.2 mag dmag2 [0.06/7.3]? Magnitude difference in Filt2
61 A1 --- Filt2 Filter used in dmag2
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/375] Internal index number
5- 32 A28 --- Names Source name(s)
34-2044 A2011 --- Note Note
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Global notes:
Note (G1): On the reference frame of the minor planets in the Solar System
(see Stefanik+ 1999ASPC..185..354S 1999ASPC..185..354S).
Note (G2): Instrument as follows:
1 = the Digital Speedometers;
2 = the Tillinghast Reflector Echelle Spectrograph (TRES).
See the "Description" section above.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Feb-2023