J/MNRAS/474/2129 Barium dwarfs with white dwarf companions (Kong+, 2018)
Three new barium dwarfs with white dwarf companions:
BD+68 1027, RE J0702+129 and BD+80 670.
Kong X.M., Bharat Kumar Y., Zhao G., Zhao J.K., Fang X.S., Shi J.R.,
Wang L., Zhang J.B., Yan H.L.
<Mon. Not. R. Astron. Soc., 474, 2129-2141 (2018)>
=2018MNRAS.474.2129K 2018MNRAS.474.2129K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Abundances
Keywords: stars: abundances - binaries: general - stars: chemically peculiar -
stars: fundamental parameters - white dwarfs
Abstract:
We report three new barium (Ba) dwarfs lying in Sirius-like systems.
They provide direct evidence that Ba dwarfs are companions to white
dwarfs (WDs). Atmospheric parameters, stellar masses and the chemical
abundances of 25 elements, including light, α, Fe-peak and
s-process elements, are derived from high-resolution and high S/N
spectra. The enhancement of s-process elements with [s/Fe] ratios
between 0.4 and 0.6 confirm them as mild barium stars. The estimated
metallicities (-0.31, -0.06 and 0.13) of BD+68 1027, RE J0702+129 and
BD+80 670 are in the range of known Ba dwarfs and giants. As expected,
the observed indices [hs/ls], [s/Fe] and [C/Fe] show an
anti-correlation with metallicity. Asymptotic giant branch (AGB)
progenitor masses are estimated for the WD companions of RE J0702+129
(1.47M☉) and BD+80 670 (3.59M☉). These confirm the
predicted range of progenitor AGB masses (1.5-4M☉) for unseen
WDs around Ba dwarfs. The surface abundances of s-process elements in
RE J0702+129 and BD+80 670 are compared with AGB models and they are
in close agreement, within the predicted accretion efficiencies and
pollution factors for Ba stars. These results support that the origin
of s-process overabundances in Ba dwarfs is similar to those of Ba
giants via the McClure hypothesis in which Ba stars accumulate
s-process elements through mass transfer from their host companions
during the AGB phase.
Description:
The three sample stars were selected from the 98 primaries of
Sirius-like binary systems in the solar neighborhood provided in a
catalogue by Holberg et al. (2013MNRAS.435.2077H 2013MNRAS.435.2077H, Cat.
J/MNRAS/435/2077). The spectra of three sample stars were obtained
using ARC Echelle Spectrograph (ARES) mounted on 3.5 m telescope
located at Apache Point Observatory(APO), during two runs: October,
November 2014.
Objects:
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RA (2000) DE Designation(s)
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18 48 48.07 +68 52 35.7 BD+68 1027 = HIP 92306
20 45 22.81 +81 04 48.8 BD+80 670 = TYC 4598-133-1
07 02 03.96 +12 57 54.9 RE J0702+129 = TYC 757-1608-1
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table12.dat 139 3 Log of observations and basic data of sample stars
(table 1) and stellar parameters (table 2)
of the programme stars
table3.dat 59 1162 All atomic-line data used and their corresponding
EWs and abundances of program stars and the Sun
table6.dat 103 59 Atmospheric parameters, stellar mass, and carbon and
s-process abundances of Ba dwarfs and CH subgiants
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Byte-by-byte Description of file: table12.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Star Star name
14- 23 A10 "date" Date Observation date
25- 28 I4 s ExpTime Exposure time
30- 35 A6 --- SpType Spectral type
37- 41 F5.2 mag Vmag V magnitude
43- 47 F5.2 mas PlxH ?=- Hipparcos parallax
49- 52 F4.2 mas e_PlxH ?=- rms uncertainty on Hipparcos parallax
54- 59 F6.2 kpc dH Distance from Hipparcos
60 A1 --- r_dH Distance from Hipparcos reference (1)
62- 66 F5.2 mas PlxG ?=- Gaia DR1 parallax
68- 71 F4.2 mas e_PlxG ?=- rms uncertainty on Gaia DR1 parallax
73- 77 F5.2 kpc dG ?=- Distance from Gaia DR1
79- 83 A5 --- Type WD type
85- 88 F4.2 Msun MWD ?=- WD mass
89 A1 --- n_MWD WD mass reference (1)
91- 94 F4.2 mag V-K V-K colour index
96- 99 F4.2 mag E(V-K) V-K colour excess
101-104 F4.2 mag VMAG Absolute V magnitude
106-109 F4.2 Msun Mass Planet mass
111-114 I4 K TeffP Effective temperature from V-K
116-119 I4 K TeffS Effective temperature from spectroscopy
121-124 F4.2 [cm/s2] loggP Surface gravity from parallax
126-129 F4.2 [cm/s2] loggS Surface gravity from spectroscopy
131-135 F5.2 [-] [Fe/H] Metallicity
137-139 F3.1 km/s Vmic Microturbulent velocity
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Note (1): References as follows:
a = Barstow et al. (2010ApJ...723.1762B 2010ApJ...723.1762B)
b = Kawka & Vennes (2010, ASP Conf. Ser., 435, 189)
c = Gianninas, Bergeron & Ruiz (2011ApJ...743..138G 2011ApJ...743..138G, Cat. J/ApJ/743/138)
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Star Star name (1)
15- 18 A4 --- Ion Ion designation
20- 27 F8.3 0.1nm lambda Wavelength
32- 36 F5.3 eV EP Excitation potential
39- 44 F6.3 --- loggf log of Oscillator Strength
47- 51 F5.1 0.1nm EW Line equivalent width
55- 59 F5.3 --- A(X) Absolute element abundances
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Note (1): BD+68 1027, BD+80 670, RE J0702+129 and the Sun.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Star Star name
15- 18 F4.2 Msun Mp ?=- Planet mass or
lower value of planet mass interval
19 A1 --- --- [-]
20- 22 F3.1 Msun Mp2 ? Upper value of planet mass interval
24- 27 I4 K Teff Effective temperature
29- 33 F5.2 [-] [Fe/H] Metallicty
35- 38 F4.2 [cm/2] logg Surface gravity
40- 44 F5.2 [-] [C/Fe] ?=- [C/Fe] abundance
46- 49 F4.2 [-] [Sr/Fe] ?=- [Sr/Fe] abundance
51- 54 F4.2 [-] [Y/Fe] ?=- [Y/Fe] abundance
56- 59 F4.2 [-] [Zr/Fe] ?=- [Zr/Fe] abundance
61- 65 F5.2 [-] [Ba/Fe] ?=- [Ba/Fe] abundance
67- 71 F5.2 [-] [La/Fe] ?=- [La/Fe] abundance
73- 77 F5.2 [-] [Ce/Fe] ?=- [Ce/Fe] abundance
79- 82 F4.2 [-] [Nd/Fe] ?=- [Nd/Fe] abundance
84- 87 F4.2 [-] [s/Fe] ?=- [s/Fe] abundance
89- 93 A5 --- Remark Remark
95-103 A9 --- Ref Reference (1)
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Note (1): References as follows:
1 = Allen & Barbuy (2006A&A...454..895A 2006A&A...454..895A, Cat. J/A+A/454/895)
2 = Pereira & Drake (2011AJ....141...79P 2011AJ....141...79P)
3 = Porto de Mello & da Silva (1997ApJ...476L..89P 1997ApJ...476L..89P)
4 = Gray & Griffin (2007AJ....134...96G 2007AJ....134...96G)
5 = Pereira (2005AJ....129.2469P 2005AJ....129.2469P)
6 = Pereira & Junqueira (2003A&A...402.1061P 2003A&A...402.1061P)
7 = Smith, Coleman & Lambert (1993ApJ...417..287S 1993ApJ...417..287S)
8 = Luck & Bond (1991ApJS...77..515L 1991ApJS...77..515L)
9 = Karinkuzhi & Goswami (2014MNRAS.440.1095K 2014MNRAS.440.1095K, Cat. J/MNRAS/440/1095)
10 = Karinkuzhi & Goswami (2015MNRAS.446.2348K 2015MNRAS.446.2348K, Cat. J/MNRAS/446/2348)
11 = Reddy et al. (2003MNRAS.340..304R 2003MNRAS.340..304R, Cat. J/MNRAS/340/304)
12 = Edvardsson et al. (1993A&A...275..101E 1993A&A...275..101E, Cat. J/A+A/275/101)
13 = North et al. (1994A&A...281..775N 1994A&A...281..775N)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 17-Feb-2021