2010A&A...523A..73E


Query : 2010A&A...523A..73E

2010A&A...523A..73E - Astronomy and Astrophysics, volume 523, A73-73 (2010/11-2)

Deep infrared imaging of close companions to austral A- and F-type stars.

EHRENREICH D., LAGRANGE A.-M., MONTAGNIER G., CHAUVIN G., GALLAND F., BEUZIT J.-L. and RAMEAU J.

Abstract (from CDS):

The search for substellar companions around stars with different masses along the main sequence is critical to understanding the different processes leading to the formation of low-mass stars, brown dwarfs, and planets. In particular, the existence of a large population of low-mass stars and brown dwarfs physically bound to early-type main-sequence stars could imply that the massive planets recently imaged at wide separations (10-100AU) around A-type stars are disc-born objects in the low-mass tail of the binary distribution and are thus formed via gravitational instability rather than by core accretion. Our aim is to characterize the environment of early-type main-sequence stars by detecting substellar companions between 10 and 500AU. The sample stars are also surveyed with radial velocimetry, providing a way to determine the impact of the imaged companions on planets at ≲10AU. High-contrast and high angular resolution near-infrared images of a sample of 38 southern A- and F-type stars were obtained between 2005 and 2009 with the instruments NaCo on the Very Large Telescope and PUEO on the Canada-France-Hawaii Telescope. Direct and saturated imaging were used in the J to Ks bands to probe the faint circumstellar environments with contrasts of ∼5x10–2 to 10–4 at separations of 0.2" and 1", respectively. Using coronagraphic imaging, we achieved contrasts between 10–5 and 10–6 at separations >5''. Multi-epoch observations were performed to distinguish comoving companions from background contaminants. This survey is sensitive to companions of A and F stars in the brown dwarf to low-mass star mass regime. About 41 companion candidates were imaged around 23 stars. Follow-up observations for 83% of these stars allowed us to identify a large number of background contaminants. We report detection of 7 low-mass stars with masses between 0.1 and 0.8M in 6 multiple systems: the discovery of an M2 companion around the A5V star HD 14943 and detection of HD 41742B around the F4V star HD 41742 in a quadruple system. We resolve the known companion of the F6.5V star HD 49095 as a short-period binary system composed of 2 M/L dwarfs. We also resolve the companions to the astrometric binaries {iota} Crt (F6.5V) and 26 Oph (F3V), and identify an M3/M4 companion to the F4V star o Gru, associated with an X-ray source. The global multiplicity fraction measured in our sample of A and F stars is ≥16%. This has a probable impact on the radial velocity measurements performed on the sample stars.

Abstract Copyright:

Journal keyword(s): stars: early type - binaries: close - surveys - astrometry - instrumentation: adaptive optics

Simbad objects: 52

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Number of rows : 52
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME Tuc Moving Group MGr 00 00 -64.0           ~ 71 0
2 NAME THA As* 00 00 -62.0           ~ 456 0
3 * lam01 Phe PM* 00 31 24.9810454848 -48 48 12.651311736   4.79 4.77     A1Va 62 0
4 * bet03 Tuc ** 00 32 43.9053745704 -63 01 53.402028960 5.15 5.13 5.09     A0V 124 0
5 HD 4293 PM* 00 44 57.0525679464 -42 40 35.612164128   6.207 5.926     F0V 48 0
6 * q02 Eri PM* 01 46 06.2629998768 -53 31 19.328527488   5.064 5.033     A1V 81 0
7 HD 14943 ** 02 22 54.6750661920 -51 05 31.659759744   6.101 5.898     A5V 45 0
8 * eta Hor ** 02 37 24.3486279936 -52 32 35.192050404   5.569 5.293     A6V 79 0
9 * s Eri SB* 02 39 47.9753006640 -42 53 30.519103344   4.81 4.75     A1Vb 79 1
10 HD 19545 PM* 03 07 50.8499336856 -27 49 52.144200912   6.338 6.170     A3V 56 0
11 HD 20888 Er* 03 17 59.0748472584 -66 55 36.667301016   6.163 6.022     A3V 66 0
12 HD 21882 PM* 03 29 55.1472825696 -42 38 03.318856548   5.955 5.753     A5V 37 0
13 * alf Cae PM* 04 40 33.7125133631 -41 51 49.504549835 4.79 4.79 4.45 4.11 3.90 F2V 125 0
14 * bet Cae PM* 04 42 03.4822983552 -37 08 39.588865224   5.42 5.05     F3IV 96 0
15 HD 31746 PM* 04 54 53.0365142976 -58 32 51.553286952   6.531 6.107     F5V 52 0
16 * eta01 Pic PM* 05 02 48.6860731776 -49 09 05.062859424   5.796 5.372     F5V 69 0
17 * tet01 Ori C SB* 05 35 16.4662967280 -05 23 22.921811880 4.20 5.15 5.13 4.91 4.73 O7Vp 1385 1
18 NAME Ori Trapezium OpC 05 35 16.5 -05 23 14           ~ 1598 1
19 * bet Pic PM* 05 47 17.0876901 -51 03 59.441135 4.13 4.03 3.86 3.74 3.58 A6V 1861 1
20 HD 41742B PM* 06 04 39.7817238552 -45 04 48.782354664   9.89 8.862     K4.5Vk: 7 0
21 HD 41742 SB* 06 04 40.1012416848 -45 04 44.095415808   6.42 5.966 7.01   F5.5V 75 0
22 HD 43940 ** 06 17 09.5630669904 -37 15 12.789463932   6.016 5.872     A2Vn 45 0
23 HD 49095 PM* 06 45 22.9403936275 -31 47 37.133210127   6.396 5.916     F6.5V 84 0
24 HD 50445 PM* 06 51 42.4207334784 -36 13 48.979898580   6.120 5.940     A3V 34 0
25 * B Car SB* 08 09 00.6369168474 -61 18 08.545898653   5.163 4.742     F6VFe-0.8CH-0.4 163 0
26 IC 2391 OpC 08 41 10.1 -52 59 28           ~ 807 0
27 HD 75171 PM* 08 44 29.9582562360 -65 49 31.550027520   6.232 6.021     A4V 43 0
28 HD 91889 PM* 10 36 32.3819362122 -12 13 48.440040258   6.22 5.71     F8V 182 0
29 * iot Crt PM* 11 38 40.0180807728 -13 12 06.981257088   5.97 5.48     F6.5V 77 0
30 TWA 27B BD* 12 07 33.50 -39 32 54.4           L3 276 0
31 HD 112934 PM* 13 00 33.5254974408 -33 03 04.769545536   6.86 6.57     A9V 39 0
32 * 66 Vir PM* 13 24 33.2485660488 -05 09 50.404470804   6.167 5.749     K2V 78 0
33 * zet Vir PM* 13 34 41.5913587272 -00 35 44.939098032 3.58 3.50 3.38 3.31 3.25 A2Van 196 0
34 * 26 Oph ** 17 00 09.5293323528 -24 59 20.901756372   6.117 5.731     F3V 57 0
35 * del Ara PM* 17 31 05.9135939049 -60 41 01.841838888 3.21 3.52 3.62     B8Vn 91 0
36 * alf Lyr dS* 18 36 56.33635 +38 47 01.2802 0.03 0.03 0.03 0.07 0.10 A0Va 2655 1
37 * lam Aql PM* 19 06 14.9386542192 -04 52 57.225885348 3.07 3.34 3.43 3.46 3.55 B8.5V 223 0
38 * nu. Tel PM* 19 48 01.1976590424 -56 21 45.399621636   5.516 5.330     A7III/IV 58 0
39 * psi Cap PM* 20 46 05.7329952443 -25 16 15.233491015   4.538 4.122     F5V 213 0
40 V* BO Mic BY* 20 47 45.0056152368 -36 35 40.769832192   10.39 9.337   8.216 K3V(e) 193 0
41 * tet Cap PM* 21 05 56.8284751494 -17 13 58.306214724 4.07 4.06 4.07 4.06 4.08 A1V 87 0
42 * iot Aqr SB* 22 06 26.2273404225 -13 52 10.850020077 3.91 4.20 4.27 4.32 4.41 B8V 112 0
43 * bet PsA PM* 22 31 30.3305233469 -32 20 45.871070532 4.32 4.30 4.29 4.27 4.25 A1Va 93 0
44 * sig Peg PM* 22 52 24.0744611045 +09 50 08.394417666   5.64   4.9   F6V 276 0
45 * del Aqr PM* 22 54 39.0062577912 -15 49 14.950434720 3.41 3.33 3.28 3.21 3.17 A3Vp 158 0
46 * alf PsA b Pl 22 57 39.04625 -29 37 20.0533           ~ 196 1
47 * alf PsA PM* 22 57 39.04625 -29 37 20.0533 1.31 1.25 1.16 1.11 1.09 A4V 1216 3
48 HD 218396 El* 23 07 28.7157209544 +21 08 03.310767492   6.21 5.953     F0+VkA5mA5 1102 0
49 HD 219482 PM* 23 16 57.6874876272 -62 00 04.312068048   6.146 5.647     F6V 120 0
50 * omi Gru PM* 23 26 36.5609994960 -52 43 17.679494676   5.901 5.522     F4V 68 0
51 HD 223011 PM* 23 46 01.2562482888 -40 10 57.236437668   6.503 6.302     A7III/IV 50 0
52 * eta Tuc ** 23 57 35.0786487048 -64 17 53.627347464   5.046 4.989     A1V 86 0

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2023.10.03-09:20:34

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