2007A&A...464..581K


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.24CEST04:44:57

2007A&A...464..581K - Astronomy and Astrophysics, volume 464, 581-599 (2007/3-3)

A brown dwarf desert for intermediate mass stars in Scorpius OB2?

KOUWENHOVEN M.B.N., BROWN A.G.A. and KAPER L.

Abstract (from CDS):

We present JHKS observations of 22 intermediate-mass stars in the Scorpius-Centaurus OB association, obtained with the NAOS/CONICA system at the ESO Very Large Telescope. This survey was performed to determine the status of (sub)stellar candidate companions of Sco OB2 member stars of spectral type A and late-B. The distinction between companions and background stars is made on the basis of a comparison to isochrones and additional statistical arguments. We are sensitive to companions with an angular separation of 0.1''-11'' (13-1430AU) and the detection limit is KS=17mag. We detect 62 stellar components of which 18 turn out to be physical companions, 11 candidate companions, and 33 background stars. Three of the 18 confirmed companions were previously undocumented as such. The companion masses are in the range 0.03M≤M≤1.19M, corresponding to mass ratios 0.06≤q≤0.55. We include in our sample a subset of 9 targets with multi-color ADONIS observations from Kouwenhoven et al. (2005A&A...430..137K). In the ADONIS survey secondaries with KS<12mag were classified as companions; those with KS>12mag as background stars. The multi-color analysis in this paper demonstrates that the simple KS=12mag criterion correctly classifies the secondaries in ∼80% of the cases. We reanalyse the total sample (i.e. NAOS/CONICA and ADONIS) and conclude that of the 176 secondaries, 25 are physical companions, 55 are candidate companions, and 96 are background stars. Although we are sensitive (and complete) to brown dwarf companions as faint as KS=14mag in the semi-major axis range 130-520AU, we detect only one, corresponding to a brown dwarf companion fraction of 0.5±0.5% (M>30MJ). However, the number of brown dwarfs is consistent with an extrapolation of the (stellar) companion mass distribution into the brown dwarf regime. This indicates that the physical mechanism for the formation of brown dwarf companions around intermediate mass stars is similar to that of stellar companions, and that the embryo ejection mechanism does not need to be invoked in order to explain the small number of brown dwarf companions among intermediate mass stars in the Sco OB2 association.

Abstract Copyright:

Journal keyword(s): binaries: visual - binaries: general - stars: formation - stars: low mass, brown dwarfs - clusters open and associations: individual: Sco OB2

VizieR on-line data: <Available at CDS (J/A+A/464/581): table2.dat table4.dat tablea1.dat tablea2.dat tablea3.dat>

Simbad objects: 84

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Number of rows : 84

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 Ass Ori OB 2 As* 05 31 26.000 +12 09 36.00           ~ 5 0
2 TYC 5478-859-1 * 09 48 56.4041736696 -10 30 32.386149806   12.79 11.70     ~ 6 0
3 HD 89715 ** 10 19 05.07255 -64 40 34.5275   5.72 5.67     A1V 49 0
4 HD 92896 * 10 41 59.65270 -63 30 26.2741   7.53 7.34     A3IV 29 1
5 HD 95324 ** 10 59 14.01166 -61 19 14.6584   6.118 6.178     B8IV 40 1
6 HD 101582 * 11 41 00.2287691962 -54 32 55.551918558   7.43 7.41     A0V 17 0
7 HD 104021 * 11 58 38.9317460548 -52 46 07.348097749   7.70 7.49     A7V 21 0
8 HD 104839 * 12 04 16.7045672461 -51 28 21.051575259   6.43 6.47     B9.5V 26 0
9 HD 105874 * 12 11 14.8132783939 -52 13 03.185465564   8.10 7.91     A6V 17 1
10 HD 106036 * 12 12 10.2739609068 -63 27 14.809116299   7.063 6.977     A2V 32 0
11 NAME Lower Centaurus Crux As* 12 19 -57.1           ~ 361 1
12 HD 107143 * 12 19 16.6043709690 -47 49 48.071668344   7.96 7.86     A1V 20 0
13 HD 108501 * 12 28 19.2607760520 -64 20 27.574132199 6.08 6.14 6.09     A0V 40 0
14 HD 109197 * 12 33 19.9292206160 -54 58 52.058020273   7.708 7.614     A2V 23 0
15 HD 109808 ** 12 38 07.25326 -55 55 52.3849           A1/2V 21 0
16 V* FH Mus El* 12 39 55.8513201361 -66 30 40.091455588   6.199 6.252     B8V 49 0
17 HD 110390 ** 12 42 27.2256910048 -61 01 06.688913161   7.35 7.20     A1V 25 0
18 HD 110461 * 12 42 49.7638510107 -55 56 49.285412751   6.029 6.057     B9V 39 0
19 HD 110698 ** 12 44 34.9624673 -57 17 12.920403   6.710 6.641     A0IV/V 25 1
20 V* V823 Cen a2* 12 56 58.2221359148 -54 35 14.487809249   6.431 6.485     ApSiCr 65 0
21 HD 114772 ** 13 13 23.35287 -50 41 59.3747   5.886 5.899     B9.5V 44 1
22 HD 115988 * 13 21 25.9078344885 -43 38 03.579384898   6.647 6.662     B9V 24 0
23 HD 117193 * 13 29 36.1666726943 -47 52 32.950557529   7.01 6.93     A1V 17 0
24 HD 119884 ** 13 47 10.5582709469 -52 16 09.313314097   6.949 6.930     A0V 20 0
25 HD 121040 * 13 54 38.3015968448 -55 44 17.992320393   7.53 7.24     A9V 35 0
26 HD 121336 ** 13 56 19.96521 -54 07 56.7142           A1V 43 0
27 HD 122259 * 14 01 45.7042537675 -39 26 19.007351452   7.70 7.54     A3IV/V 19 0
28 HD 122982 * 14 06 08.2356097459 -44 41 20.711153799   7.24 7.23     A0V 20 0
29 HD 123445 * 14 08 51.8859074874 -43 28 14.801932182   6.11 6.17     B9V 58 0
30 HD 124620 * 14 16 31.9635295806 -57 17 50.986561286   7.38 7.18     B9IV 17 0
31 HD 127215 * 14 31 14.3793856953 -40 39 21.349094592   7.62 7.47     A1V 22 0
32 HD 128819 * 14 40 17.6464592221 -40 50 30.052649830   6.580 6.649     B8/9V 34 1
33 V* IT Lup a2* 14 40 19.2712157079 -45 47 37.826912719   6.504 6.615     ApSi 53 0
34 HD 131399 ** 14 54 25.30919 -34 08 34.0412   7.19 7.08 8.33   A1V 36 0
35 HD 131461 ** 14 54 54.47833 -36 25 49.2930   7.3 7.23     A0/1V 19 1
36 GSPC S273-E * 14 56 52.0 -44 49 15           ~ 15 0
37 V* HZ Lup a2* 15 06 33.1977060064 -30 55 06.536906644   5.893 5.977     ApSi 97 0
38 V* HR Lup a2* 15 08 12.1245697358 -40 35 02.158712447 5.25 5.65 5.79     B8IVSi 151 1
39 HD 134837 * 15 13 07.6613057814 -36 05 29.114095971   5.996 6.079     B8V 42 1
40 HD 136164 * 15 20 13.3925969213 -34 55 31.571564890   7.97 7.76     A2V 23 0
41 HD 136347 ** 15 21 30.09403 -38 13 07.2862   6.480 6.538     ApSi 62 1
42 NAME Upper Centaurus Lupus As* 15 24 -41.9           ~ 366 1
43 HD 137919 ** 15 30 21.29078 -41 55 08.4957           B9.5V 26 0
44 HD 138138 ** 15 31 17.20862 -33 49 11.4308           A2/3V 38 0
45 HD 138221 * 15 31 50.2299849204 -32 52 52.013844928   6.540 6.488     B7V 40 0
46 HD 138343 * 15 32 10.3300687362 -21 58 00.560013162   7.26 7.23     B9V 27 0
47 HD 140817 ** 15 47 04.4641248452 -35 30 37.226520746   6.89 6.92     A0V 42 1
48 HD 140840 * 15 47 06.1670334211 -35 31 04.938686406   7.26 7.26     B9/A0V 29 0
49 HD 142315 SB* 15 54 41.5960624501 -22 45 58.512729751   6.887 6.861     B9V 101 0
50 * 47 Lib Ro* 15 55 00.3736680551 -19 22 58.628549883   5.930 5.957     B2/3V 113 0
51 HD 143567 * 16 01 55.4546289923 -21 58 49.397570493   7.27 7.19 7.87   B9V 105 0
52 V* LM Lup a2* 16 04 44.4890499672 -39 26 04.780382706   6.86 6.94   6.968 ApSiCr 60 1
53 HD 144175 * 16 05 19.1476601945 -23 40 08.829045668   7.70 7.64     B9V 34 0
54 HD 144254 ** 16 05 43.3891779201 -21 50 19.540607253   7.96 7.78     A0V 32 0
55 HD 144118 * 16 05 46.27839 -39 50 35.9336   8.14 7.96     A5V 21 1
56 HD 144569 ** 16 07 04.6738866107 -16 56 35.755722772   8.06 7.90     B9.5V 32 0
57 HD 145145 * 16 07 08.1659909266 +49 04 59.121008585   7.88 7.60     A2 10 0
58 HD 144586 * 16 07 14.9288660424 -17 56 09.736020891   7.91 7.81     B9V 36 0
59 BD-14 4350 PM* 16 07 15.2714663900 -14 23 35.212241832   11.82 10.65     ~ 11 0
60 HD 144844 V* 16 08 43.7199351602 -23 41 07.451972503 5.59 5.90 5.88     B9V 141 0
61 HD 144925 ** 16 09 02.6012201339 -18 59 44.039571243   7.98 7.78     A0V 48 1
62 HD 144981 ** 16 09 20.8883510830 -19 27 25.958998409   8.22 8.04     A0V 49 0
63 HD 145189 ** 16 10 25.3553081546 -23 06 23.387071540   8.00 7.79     A3III/IV 31 0
64 NAME Upper Sco Association As* 16 12 -23.4           ~ 1054 1
65 HD 145554 * 16 12 21.8333006041 -19 34 44.570507060   7.77 7.64     B9V 78 0
66 HD 145792 a2* 16 13 45.49839 -24 25 19.5421         6.14 B6IV 115 0
67 HD 145880 * 16 14 57.7662971068 -39 37 40.122795395   7.18 7.16     B9.5V 27 0
68 NAME ASSOC II SCO As* 16 15 -24.2           ~ 1142 1
69 HD 146285 Ro* 16 16 25.1727655978 -24 59 19.465473164   8.12 7.94   7.47 B8V 66 0
70 HD 146331 Ro* 16 16 50.6247453979 -25 51 46.704565035   8.69 8.30     B9V 33 0
71 HD 147001 V* 16 21 27.0324154185 -48 11 19.043359873   6.456 6.498     B7V 26 0
72 HD 147432 ** 16 22 51.77663 -23 07 07.5271           A1III/IV 35 0
73 HD 147553 ** 16 23 56.71426 -33 11 57.8305   6.47 6.46     B9.5V(n)+A1V(n) 49 0
74 HD 147701 Ro* 16 24 21.3184734300 -25 01 31.448891118 9.66 9.74 9.20   7.42 B5III 114 0
75 HD 147809 ** 16 24 59.1476819338 -25 21 17.984250932   8.99 8.63     A1V 50 0
76 HD 147888 ** 16 25 24.2937199705 -23 27 36.816821785 6.71 7.05 6.74     B3/4V 197 0
77 HD 147932 Ro* 16 25 35.0836168833 -23 24 18.788751256 7.24 7.59 7.27     B5V 106 0
78 HD 148562 TT* 16 29 54.5956585494 -24 58 46.075096179 8.08 7.99 7.81     A2V 55 0
79 HD 148716 * 16 31 11.0701008056 -29 59 52.419135469   8.93 8.53     F3V 32 0
80 HD 150193 Be* 16 40 17.9242900066 -23 53 45.192676418 9.69 9.32 8.79 8.41   B9.5Ve 293 0
81 HD 150645 * 16 44 21.0946513964 -44 22 43.477865487   8.19 7.94     A3V 15 0
82 HD 150742 * 16 44 42.5932088698 -40 50 22.829911792   5.528 5.628     B3V 64 1
83 HD 154117 * 17 04 27.8223079195 -23 23 25.935831562   8.09 7.09     G8/K0III 16 0
84 HD 154310 * 17 06 20.1896222098 -37 13 39.329253567   6.05 5.98     A2IV 25 1

    Equat.    Gal    SGal    Ecl

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2020.10.24-04:44:57

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