J/AJ/156/37 Photometry & Li abund. of cool dwarfs in M35 (Anthony-Twarog+, 2018)
Li in open clusters: cool dwarfs in the young, subsolar-metallicity cluster
M35 (NGC 2168).
Anthony-Twarog B.J., Deliyannis C.P., Harmer D., Lee-Brown D.B.,
Steinhauer A., Sun Q., Twarog B.A.
<Astron. J., 156, 37 (2018)>
=2018AJ....156...37A 2018AJ....156...37A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, dwarfs ; Stars, G-type ; Stars, K-type ;
Photometry, UBVRI ; Radial velocities ; Rotational velocities ;
Equivalent widths ; Abundances
Keywords: open clusters and associations: individual (NGC 2168) -
stars: abundances
Abstract:
Hydra spectra of 85 G-K dwarfs in the young cluster M35 near the
Li 6708 Å line region are analyzed. From velocities and Gaia astrometry,
78 are likely single-star members that, combined with previous work,
produce 108 members with Teff ranging from 6150 to 4000 K as defined by
multicolor, broadband photometry, E(B-V)=0.20, and [Fe/H]=-0.15, though
there are indications the metallicity may be closer to solar. The Lithium
abundance A(Li) follows a well-delineated decline from 3.15 for the
hottest stars to upper limits =<1.0 among the coolest dwarfs. Contrary
to earlier work, M35 includes single stars at systematically higher A(Li)
than the mean cluster relation. This subset exhibits higher VROT than
the more Li-depleted sample and, from photometric rotation periods, is
dominated by stars classed as convective (C); all others are interface (I)
stars. The cool, high-Li rapid rotators (RRs) are consistent with models
that simultaneously consider rapid rotation and radius inflation; RRs
hotter than the Sun exhibit excess Li depletion, as predicted by the
models. The A(Li) distribution with color and rotation period, when
compared to the Hyades/Praesepe and the Pleiades, is consistent with
gyrochronological analysis placing M35's age between the older M34 and
younger Pleiades. However, the Pleiades display a more excessive range
in A(Li) and rotation period than M35 on the low-Li, slow-rotation side
of the distribution, with supposedly younger stars at a given Teff in
the Pleiades spinning slower, with A(Li) reduced by more than a factor
of four compared to M35.
Description:
Spectroscopic data were obtained using the WIYN 3.5 m telescope and the
Hydra multiobject spectrograph over three nights in 2001 March. The same
configuration of 85 star fibers with eight sky fibers was repeated twice
each night for 2 hr each, with a cumulative total of 12 hr for the
configuration. Four to five bright radial-velocity standards were observed
each night, and a complete set of solar/sky observations through all
functional fibers was obtained each afternoon.
To get a handle on the Teff for abundance estimation, we include in
Table 1 the complete set of UBVRI CCD observations from the survey by
C. P. Deliyannis et al. (2018, in preparation). The photometry is based
on frames taken with the former T2KA 2Kx2K CCD chip at the f/7.5 focus
of the KPNO 0.9 m telescope. Each field has a 23'x23' field of view, with
the frames arranged in a mosaic of five fields, one central field and four
tiled around the center, for a total field of view of 40'x40'. The
photometry is calibrated to the standard system as defined by Landolt
(1992, Cat. II/183).
Splot, part of the spectrum analysis suite in IRAF, was used to measure
equivalent widths of the line blend incorporating the Li doublet at
6707.8 Å and the Fe I line at 6707.45 Å; the EW measurements as
summarized in Table 3 are an average of three independent measurements
of each line.
Objects:
--------------------------------------------
RA (ICRS) DE Designation(s)
--------------------------------------------
06 08 54 +24 20.0 M35 = NGC 2168
--------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 103 85 Photometry for M35 stars
table2.dat 77 85 Basic information for M35 stars
table3.dat 34 85 Measured and derived lithium data
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See also:
II/183 : UBVRI Photometric Standards (Landolt 1992)
J/MNRAS/306/361 : UBVI CCD photometry of M35 (NGC 2168) (Sung+ 1999)
J/ApJ/546/1006 : VRI photometry of M35 (Barrado y Navascues+, 2001)
J/AJ/133/394 : Low-mass binary companions in M35 (McNamara+, 2007)
J/ApJ/695/679 : Stellar rotation in M35 (Meibom+, 2009)
J/AJ/139/1383 : Radial velocities in M35 (NGC 2168) (Geller+, 2010)
J/AJ/148/85 : WIYN open cluster study. LXII. Photometry of M35
(Thompson+, 2014)
J/A+A/575/A120 : DANCe study of M35 (NGC 2168) (Bouy+, 2015)
J/AJ/150/10 : WOCS. LXVI. Radial velocity survey in M35 (Leiner+, 2015)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- WOCS WOCS identification ([GMB2010] WOCS NNNFFF
in Simbad) (G1)
8- 15 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
17- 24 F8.5 deg DEdeg Declination in decimal degrees (J2000)
26- 31 F6.3 mag Umag [15.375/18.482]? KPNO/WIYN Johnson U band
magnitude
33- 37 F5.3 mag e_Umag [0.008/0.059]? Error in Umag
39- 44 F6.3 mag Bmag [15.256/19.313] KPNO/WIYN Johnson B band magnitude
46- 50 F5.3 mag e_Bmag [0.007/0.091] Error in Bmag
52- 57 F6.3 mag Vmag [14.514/17.924] KPNO/WIYN Johnson V band magnitude
59- 63 F5.3 mag e_Vmag [0.006/0.034] Error in Vmag
65- 70 F6.3 mag Rmag [14.049/17.062] KPNO/WIYN Cousins R band magnitude
72- 76 F5.3 mag e_Rmag [0.008/0.032] Error in Rmag
78- 83 F6.3 mag Imag [13.586/16.239] KPNO/WIYN Cousins I band magnitude
85- 89 F5.3 mag e_Imag [0.007/0.033] Error in Imag
91 I1 --- NU [0/9] Number of U frames
93- 94 I2 --- NB [1/13] Number of B frames
96- 97 I2 --- NV [2/14] Number of V frames
99-100 I2 --- NR [2/13] Number of R frames
102-103 I2 --- NI [2/13] Number of I frames
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- WOCS WOCS identification ([GMB2010] WOCS NNNFFF
in Simbad) (G1)
8- 10 I3 --- IDA [130/362]? Identification number from
Meibom et al. (2009, J/ApJ/695/679)
12- 14 I3 --- IDB [192/413]? Identification number from
McNamara & Sekiguchi (1986AJ.....91..557M 1986AJ.....91..557M)
16- 18 I3 --- IDC [168/196]? Identification number from
Cudworth (1971AJ.....76..475C 1971AJ.....76..475C)
20- 21 I2 % MemA [70/96]? Membership probability from IDA
23- 24 I2 % MemB [68/93]? Membership probability from IDB
26- 27 I2 % MemC [67/90]? Membership probability from IDC
29- 33 A5 --- MC Membership class (1)
35- 40 F6.2 km/s RV-LE [-10.17/-5.87]? Radial velocity from
Leiner et al. (2015, J/AJ/150/10)
42- 45 F4.2 km/s e_RV-LE [0.04/4.47]? Error in RV-LE
47- 50 F4.1 km/s Vrot-LE [10/39.6]? Rotational velocity from
Leiner et al. (2015, J/AJ/150/10)
52- 54 F3.1 km/s e_Vrot-LE [0.1/3]? Error in Vrot-LE
56- 62 F7.2 km/s RV [-18.49/-0.95]? Radial velocity from this work
63 A1 --- u_RV [:] Uncertainty flag on RV
65- 68 F4.2 km/s e_RV [0.26/1.39]? Error in RV
70- 73 F4.1 km/s Vrot [10.3/35]? Rotational velocity from this work
75- 77 F3.1 km/s e_Vrot [0.1/5.3]? Error in Vrot
--------------------------------------------------------------------------------
Note (1): Membership class as follows:
SM = Single-star member;
SM,RR = Single-star rapid rotator member;
SM,X = Single-star X-ray member;
GNM = Gap star nonmember;
SB1,M = Single-lined spectroscopic binary member.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- WOCS WOCS identification ([GMB2010] WOCS NNNFFF
in Simbad) (G1)
8- 11 F4.2 mag (B-V) [0.72/1.48] The (B-V) color index
13- 17 F5.1 10-13m EW(Li) [0.0/292.7] Equivalent width of Li line
19- 21 I3 --- S/N [8/117] Signal-to-noise per pixel ratio
23 A1 --- l_A(Li) [<] Limit flag on A(Li)
24- 27 F4.2 [-] A(Li) [0.64/3.17] Lithium abundance
29- 32 F4.2 [-] e_A(Li) [0.03/0.17]? Error in A(Li)
34 I1 --- f_A(Li) [0/2]? Lithium abundance code (1)
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Note (1): Lithium abundance code as follows:
0 = 3σ detection;
1 = Upper limit value limited by S/N;
2 = Upper limit value limited by the parameter range of the
curve-of-growth-based grid.
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Global notes:
Note (G1): For 74 stars, the identification number listed is the WOCS ID; the
remaining 11 without WOCS IDs have been assigned the designation F1 through
F11.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 21-Jan-2019