2019A&A...626A.127J


Query : 2019A&A...626A.127J

2019A&A...626A.127J - Astronomy and Astrophysics, volume 626A, 127-127 (2019/6-1)

Barium and related stars, and their white-dwarf companions. I. Giant stars.

JORISSEN A., BOFFIN H.M.J., KARINKUZHI D., VAN ECK S., ESCORZA A., SHETYE S. and VAN WINCKEL H.

Abstract (from CDS):


Context. Barium and S stars without technetium are red giants and are suspected of being members of binary systems due to their overabundances in heavy elements. These elements are produced by the s-process of nucleosynthesis, despite the stars not being evolved enough to be able to activate the s-process in their interiors. A companion formerly on the asymptotic giant branch (now a white dwarf) is supposed to be responsible for the barium- and S-star enrichment in s-process elements through mass transfer.
Aims. This paper provides both long-period and revised orbits for barium and S stars, adding to previously published orbits. The sample of barium stars with strong anomalies (i.e., those classified as Ba3, Ba4, or Ba5 in the Warner scale) comprises all known stars of that kind, and in that sense forms a complete sample that allows us to investigate several orbital properties of these post-mass-transfer binaries in an unbiased way.
Methods. Orbital elements are derived from radial velocities collected from a long-term radial-velocity monitoring campaign performed with the HERMES spectrograph mounted on the Mercator 1.2m telescope. These new measurements were combined with older, CORAVEL measurements. With the aim of investigating possible correlations between orbital properties and abundances, we also collected a set of abundances for barium stars with orbital elements that is as homogeneous as possible. When unavailable in the literature, abundances were derived from high-resolution HERMES spectra.
Results. We find orbital motion for all barium and extrinsic S stars monitored (except for the mild barium star HD 95345). We obtain the longest period known so far for a spectroscopic binary involving an S star, namely 57 Peg with a period of the order of 100-500yr. We present the mass distribution for the barium stars, which ranges from 1 to 3M, with a tail extending up to 5M in the case of mild barium stars. This high-mass tail is mostly comprised of high-metallicity objects ([Fe/H]≥-0.1). The distribution of the companion masses was extracted from the barium-star mass distribution combined with the finding that Q∼f(MBa,MWD)/sin3i=MWD3/(MBa+MWD)2 is peaked at 0.057±0.009 and 0.036±0.027M for strong and mild barium stars, respectively (f(MBa, MWD) is the mass function obtained from the orbital elements of spectroscopic binaries with one observable spectrum). Mass functions are compatible with WD companions whose masses range from 0.5 to 1M. Strong barium stars have a tendency to be found in systems with shorter periods than mild barium stars, although this correlation is rather lose, with metallicity and WD mass also playing a role. Using the initial-final mass relationship established for field WDs, we derived the distribution of the mass ratio q'=MAGB,ini/MBa (where MAGB,ini is the WD progenitor initial mass, i.e., the mass of the former primary component of the system) which is a proxy for the initial mass ratio (the less mass the barium star has accreted, the better the proxy). It appears that the distribution of q' is highly nonuniform, and significantly different for mild and strong barium stars, the latter being characterized by values mostly in excess of 1.4, whereas mild barium stars occupy the range 1-1.4.
Conclusions. The orbital properties presented in this paper pave the way for a comparison with binary-evolution and nucleosynthesis models, which should account for the various significant correlations found between abundances and dynamical parameters (e.g. between MBa on one hand and MWD, [Fe/H], and [s/Fe] on the other hand, between q' and [s/Fe], between P and e, and between P and [s/Fe] altogether).

Abstract Copyright: © ESO 2019

Journal keyword(s): binaries: spectroscopic - white dwarfs - stars: peculiar - stars: AGB and post-AGB - stars: abundances

VizieR on-line data: <Available at CDS (J/A+A/626/A127): stars.dat table2.dat table3.dat>

Simbad objects: 53

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Number of rows : 53
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 V* DT Psc Sy* 01 14 04.9051442688 +28 31 46.448476788   8.016 6.347     S3+/2- 119 0
2 * omi Cet Mi* 02 19 20.79210 -02 58 39.4956   7.63 6.53 5.03   M5-9IIIe+DA 1486 0
3 HD 19014 Pe* 02 44 51.8145270264 -85 09 32.321011968   9.94 8.21     K2III 26 0
4 HD 18182 Pe* 02 55 11.0938072080 -04 18 59.871586536   10.02 8.97     G8/K0III 27 0
5 HD 22589 SB* 03 37 55.2473522232 -06 58 28.318211112   9.72 9.00     G5II 25 0
6 HD 24035 SB* 03 43 42.5926451400 -72 36 32.798908692 9.70 9.74 8.51     K2:IIICN2Ba3CH4C21- 47 0
7 * omi Ori S* 04 52 31.9624004856 +14 15 02.311506180   6.458 4.721     M3SIII 211 0
8 BD+79 156 S* 04 55 44.9993026824 +79 59 59.984445300   11.20 9.55     S4/2 19 0
9 HD 40430 SB* 05 58 20.3999304048 -10 52 29.143536600 9.77 9.08 8.07     K0Ba1 34 0
10 V* HR CMa EB* 06 32 46.8731198040 -11 09 58.987412460 8.12 7.35 6.24 5.49 5.01 G9III:Ba3.5 172 0
11 HD 288833 S* 06 36 12.1133753592 +01 57 29.168329464   11.31 9.40     S3/2 21 0
12 HD 50843 Pe* 06 55 07.1013440064 +04 37 25.379427252   9.15 8.10     G8III 30 0
13 HD 51959 SB* 06 59 10.0961767488 -07 06 32.033021256   10.05 8.92     K1IIIBa1 42 0
14 CD-28 3719 Sy* 07 01 09.1555114272 -29 06 25.046471988   12.10 10.59     S6,8e 22 0
15 HD 53199 SB* 07 04 48.2850310560 +13 14 19.215205260   10.06 9.07     G5 31 0
16 NGC 2420 173 SB* 07 38 26.9655810288 +21 33 31.300526016   12.66 11.76     ~ 33 0
17 V* NQ Pup S* 07 53 05.2704648648 -11 37 29.352872136   9.34 7.64     S4.5/2 87 0
18 HD 65854 Pe* 08 03 32.3686216416 +54 09 35.186960844   9.37 8.40     K0 41 0
19 V* PV UMa SB* 09 03 32.2721549112 +53 06 29.817440280   7.86 6.86     G7III:Ba0.5 70 0
20 * 58 Leo ** 11 00 33.6471432816 +03 37 02.992384200   6.007 4.838     K0.5IIIFe-0.5 156 0
21 * 56 UMa SB* 11 22 49.5779879928 +43 28 57.714470868 6.86 6.04 5.03 4.30 3.81 G8IIIa 140 0
22 HD 101013 SB* 11 37 53.0008333680 +50 37 05.469784824   7.200 6.113     G9:IIIb:Ba2.5 139 0
23 HD 101079 SB* 11 37 54.2571767208 -01 09 03.908168172   9.20 8.18     K1Ba1 21 0
24 * omi Vir PM* 12 05 12.5404884 +08 43 58.749788 5.75 5.11 4.12 3.38 2.89 G8IIICN0.5CH1Ba1 277 0
25 V* V420 Hya Sy* 12 24 32.5099977120 -28 18 55.685798892   11.48 10.24     S4,6e 26 0
26 HD 119185 Pe* 13 41 57.5120926632 -13 01 39.811506996   9.87 8.91     G8III(pBa) 41 0
27 HD 120620 SB* 13 50 41.6578375656 -04 16 04.875004200   10.78 9.60     K0(III) 26 0
28 HD 121447 Pe* 13 55 46.9655016048 -18 14 56.486226336 11.50 9.61 7.80     C2,1_CH4:_Ba4 120 0
29 HD 123949 SB* 14 10 59.3114487936 -19 08 38.227483320 11.40 10.10 8.70     K1pBa 43 0
30 * alf Boo RG* 14 15 39.67207 +19 10 56.6730 2.46 1.18 -0.05 -1.03 -1.68 K1.5IIIFe-0.5 2223 0
31 CD-25 10393 S* 14 32 41.8696932336 -26 10 01.133088312   12.79 10.37     S3,3 10 0
32 HD 134698 Pe* 15 11 41.7016592856 -10 30 27.566198280   9.982 8.870     G8III 25 0
33 BD-10 4311 SB* 16 24 13.1941511520 -11 13 06.510639216   10.48 9.88     G0Ba1 35 0
34 HD 165141 RS* 18 07 00.2466690936 -48 14 50.204205744   8.10 7.10     K0II/IIIBa1+DA: 65 0
35 V* V530 Lyr S* 18 30 34.5709214544 +36 14 56.999721696   9.01 7.44     S3+/1-III: 54 0
36 V* V915 Aql S* 19 03 09.8933874288 +12 15 08.407658016   10.38 8.42     S5+/2 42 0
37 V* T Sgr S* 19 16 14.4361485576 -16 58 17.076889992   11.81 7.10     S4.5-6/5.5-6e 130 0
38 HD 183915 SB* 19 31 25.5039458808 +11 37 40.623930768   8.65 7.29     K0III:Ba3.5 74 0
39 V* V4638 Sgr S* 19 34 00.3908425752 -20 55 56.148163428   10.78 9.12     S3*4 13 0
40 HD 189581 S* 20 00 38.4057760224 +01 21 39.754195740   10.19 8.45     S4*2 28 0
41 HD 191589 S* 20 09 32.9862045768 +33 40 53.851811988   8.772 7.244     M0SIb/II 55 0
42 V* V2012 Cyg S* 20 17 11.0550768024 +31 33 18.075697344   11.13 9.27     S3,1 27 0
43 HD 196673 ** 20 37 44.3242645 +33 21 59.371434           K0pBa+G5III 56 0
44 V* ER Del Sy* 20 42 46.4988142800 +08 41 13.540747956   12.17 10.39     S5.5 33 0
45 HD 199394 SB* 20 55 09.1153259184 +46 21 00.572015340   8.001 6.984     K0III 65 0
46 HD 199939 SB* 20 58 43.4942605752 +44 24 52.482256560   8.74 7.44     G9III:Ba4 82 0
47 BD+31 4391 S* 21 15 41.1687655320 +31 45 39.469496148   11.53 9.690 9.13   S2.5/3.5 11 0
48 * zet Cap SB* 21 26 40.0263390 -22 24 40.804197 5.35 4.75 3.74 3.09 2.65 G4Ib:Ba2 273 1
49 HD 211954 SB* 22 21 17.6106697704 -27 14 20.859530316   11.3 10.14     G8/K0(III) 21 0
50 HD 215336 S* 22 43 49.1694802248 +33 55 34.301740944   9.48 7.81     Swk 22 0
51 HD 216219 Pe* 22 50 52.1530053936 +18 00 07.703208072   8.06 7.44     G1II-III:Fe-1CH0.5 113 0
52 * 56 Peg SB* 23 07 06.7390851 +25 28 05.732922 7.20 6.06 4.74 3.74 3.07 K0.5II:Ba1CN-2CH-0.5 256 0
53 * 57 Peg S* 23 09 31.4573825 +08 40 37.763634   6.48 5.14     M4S 125 0

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2022.05.28-09:37:03

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