2017A&A...602A..38M


Query : 2017A&A...602A..38M

2017A&A...602A..38M - Astronomy and Astrophysics, volume 602A, 38-38 (2017/6-1)

Searching for chemical signatures of brown dwarf formation.

MALDONADO J. and VILLAVER E.

Abstract (from CDS):

Context. Recent studies have shown that close-in brown dwarfs in the mass range 35-55 MJup are almost depleted as companions to stars, suggesting that objects with masses above and below this gap might have different formation mechanisms.
Aims. We aim to test whether stars harbouring massive brown dwarfs and stars with low-mass brown dwarfs show any chemical peculiarity that could be related to different formation processes.
Methods. Our methodology is based on the analysis of high-resolution echelle spectra (R∼57000) from 2-3m class telescopes. We determine the fundamental stellar parameters, as well as individual abundances of C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, and Zn for a large sample of stars known to have a substellar companion in the brown dwarf regime. The sample is divided into stars hosting massive and low-mass brown dwarfs. Following previous works, a threshold of 42.5MJup was considered. The metallicity and abundance trends of the two subsamples are compared and set in the context of current models of planetary and brown dwarf formation.
Results. Our results confirm that stars with brown dwarf companions do not follow the well-established gas-giant planet metallicity correlation seen in main-sequence planet hosts. Stars harbouring massive brown dwarfs show similar metallicity and abundance distribution as stars without known planets or with low-mass planets. We find a tendency of stars harbouring less-massive brown dwarfs of having slightly higher metallicity, [XFe/Fe] values, and abundances of ScII, MnI, and NiI than the stars having the massive brown dwarfs. The data suggest, as previously reported, that massive and low-mass brown dwarfs might present differences in period and eccentricity.
Conclusions. We find evidence of a non-metallicity dependent mechanism for the formation of massive brown dwarfs. Our results agree with a scenario in which massive brown dwarfs are formed as stars. At high metallicities, the core-accretion mechanism might become efficient in the formation of low-mass brown dwarfs, while at lower metallicities low-mass brown dwarfs could form by gravitational instability in turbulent protostellar discs.

Abstract Copyright: © ESO, 2017

Journal keyword(s): techniques: spectroscopic - stars: abundances - stars: late-type - planetary systems - planetary systems

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 HD 4747 SB* 00 49 26.7612113944 -23 12 44.865754071 8.244 7.927 7.155 6.732 6.344 G8/K0V 143 0
2 HD 5388 PM* 00 55 11.8899464173 -47 24 21.476331461   7.21 6.72     F6V 63 1
3 CD-23 395 PM* 01 06 02.0494092766 -22 27 11.353493137   11.29 10.21     ~ 51 1
4 * 109 Psc PM* 01 44 55.8251018821 +20 04 59.336256238   6.984 6.279     G3Va 261 2
5 HD 13189 * 02 09 40.1721335781 +32 18 59.160743793   9.04 7.56     K1II-III 75 1
6 V* V450 And BY* 02 12 54.9902695034 +40 40 06.222270192   7.880 7.21 7.71   G5V 94 1
7 HD 14348 PM* 02 19 52.9252134421 +31 20 14.917696454       6.8   F5 32 0
8 HD 14651 PM* 02 22 00.8543574589 +04 44 48.326595993   9.01 8.25     G5V 39 1
9 HD 16760 ** 02 42 21.3071467622 +38 37 07.139224707   9.45 8.76     G2V 77 1
10 HD 22781 PM* 03 40 49.5245887391 +31 49 34.648862348   9.628 8.766 8.45   K0 40 1
11 HD 283668 PM* 04 27 52.9092842784 +24 26 41.877432536   10.32   8.8   K2 61 0
12 HD 29587 SB* 04 41 36.3164521477 +42 07 06.420947055 7.940 7.890 7.280 6.74 6.39 G2V 145 1
13 HD 30246 PM* 04 46 30.3864259988 +15 28 19.348842103   8.954 8.280 7.914 7.569 G5 121 1
14 * pi. Men PM* 05 37 09.8851202601 -80 28 08.831347245   6.25 5.67     G0V 277 1
15 HD 38529 PM* 05 46 34.9129896843 +01 10 05.512540812       5.4   G8III/IV 324 2
16 HD 39392 PM* 05 53 18.9953164876 +22 04 19.747487623   8.94 8.38     F8 19 0
17 BD-13 2130 * 07 37 09.2333520617 -13 54 23.954320858   11.31 10.04     G5IV-V/K2III 59 1
18 HD 65430 SB* 07 59 33.9366319995 +20 50 38.194256358 9.004 8.494 7.649 7.195 6.776 K0V 104 1
19 HD 72946 PM* 08 35 51.2665915520 +06 37 21.970611710 8.23     6.7   G8-V 113 0
20 HAT-P-13 * 08 39 31.8073600797 +47 21 07.275628863   11.15 10.42 10.40   G4 119 2
21 HD 77065 SB* 09 00 47.4444860219 +21 27 13.363829865   9.65   8.3   K2 43 0
22 BD+26 1888 PM* 09 02 30.6351403612 +25 53 21.929969749       8.9   K7 21 0
23 BD+20 2457 * 10 16 44.8671846183 +19 53 29.010025880   10.99 9.74     K2 53 1
24 HD 89707 SB* 10 20 49.9820182134 -15 28 47.680757393   7.74 7.19     G2VFe-1.5CH-0.8 128 0
25 HD 92320 PM* 10 40 56.9097500047 +59 20 33.015278641   9.06 8.38     F2-F5Ib 44 1
26 * 11 Com PM* 12 20 43.0255802451 +17 47 34.339258907   5.74 4.74     G8+IIIFe-1 153 1
27 NGC 4349 127 * 12 24 35.4709937902 -61 49 11.859118499   12.85 10.82     ~ 42 1
28 HD 114762 SB* 13 12 19.7467346230 +17 31 01.611425890 7.78         F9VgF8mF4+M6?V 524 1
29 HD 122562 PM* 14 02 21.1637885146 +20 52 52.744187806   8.70 7.69     G5 25 0
30 HD 132032 PM* 14 56 43.9307008713 +13 08 57.142610146 8.850 8.710 8.110     G5 26 0
31 HD 131664 * 15 00 06.0799727760 -73 32 07.226474399   8.82 8.13     G3V 62 1
32 HD 134113 SB* 15 07 46.5001038610 +08 52 47.210828867   8.83   7.9   F9 118 0
33 HD 136118 PM* 15 18 55.4730161019 -01 35 32.597619958   7.46 6.94     F7V 117 1
34 * iot Dra V* 15 24 55.7746265 +58 57 57.834445 5.68 4.45 3.29 2.51 1.91 K2III 382 1
35 HD 137510 PM* 15 25 53.2707121018 +19 28 50.529629119   6.872 6.241     G0IV-V 103 0
36 HD 140913 SB* 15 45 07.4493001052 +28 28 11.743016199   8.664 8.053     G0V 93 0
37 HD 156846 ** 17 20 34.3109259866 -19 20 01.494393975 7.20 7.10 6.52     G1V 98 1
38 HD 160508 PM* 17 39 12.6965931034 +26 45 27.145116354   8.62 8.11     F8V 29 0
39 HD 162020 * 17 50 38.3545681675 -40 19 06.080050505   10.11 9.12     K3V 136 1
40 HD 167665 PM* 18 17 23.7584695845 -28 17 20.201725932   6.94 6.40     F9VFe-0.8CH-0.4 94 1
41 HD 168443 PM* 18 20 03.9331764016 -09 35 44.609316076   7.62 6.92     G6V 292 1
42 HD 174457 SB* 18 50 02.0627482461 +15 18 41.424232657       7.2   F8 50 0
43 HD 175679 * 18 56 25.6034297914 +02 28 16.281339096   7.106 6.132     G8III 41 1
44 HD 180314 PM* 19 14 50.2087958105 +31 51 37.259468042   7.63 6.608 6.41   K0 42 1
45 KOI-415 Ro* 19 33 13.4495838492 +41 36 22.965658614           ~ 39 0
46 HD 190228 PM* 20 03 00.7728097338 +28 18 24.684933114   8.094 7.296     G5IV 159 1
47 * 15 Sge PM* 20 04 06.2209062328 +17 04 12.677429047   6.390 5.788 5.4   G0V 351 0
48 HD 191760 PM* 20 13 26.7453265517 -46 12 03.702248782   8.91 8.25     G3IV/V 39 1
49 HD 202206 PM* 21 14 57.7684954746 -20 47 21.162361638   8.79 8.07     G6V 204 1
50 HD 209262 PM* 22 01 54.1217950769 +04 46 13.623839900   8.68 8.02     G6V 28 0
51 BD+24 4697 PM* 23 01 39.3221231240 +25 47 16.540578750       9.2   K2 19 0
52 HD 217786 PM* 23 03 08.2070401277 -00 25 46.677731304   8.360 7.779 7.60   F8V 63 1
53 HD 219077 PM* 23 14 06.5879721389 -62 42 00.012417294   6.91 6.12     G8V+ 101 1

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2021.12.03-16:40:09

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