2020A&A...633L...2M


C.D.S. - SIMBAD4 rel 1.7 - 2021.05.06CEST19:55:09

2020A&A...633L...2M - Astronomy and Astrophysics, volume 633, L2-2 (2020/1-1)

A dusty benchmark brown dwarf near the ice line of HD 72946.

MAIRE A.-L., BAUDINO J.-L., DESIDERA S., MESSINA S., BRANDNER W., GODOY N., CANTALLOUBE F., GALICHER R., BONNEFOY M., HAGELBERG J., OLOFSSON J., ABSIL O., CHAUVIN G., HENNING T. and LANGLOIS M.

Abstract (from CDS):

Context. HD 72946 is a bright and nearby solar-type star hosting a low-mass companion at long period (P∼16yr) detected with the radial velocity (RV) method. The companion has a minimum mass of 60.4∼2.2MJ and might be a brown dwarf. Its expected semi-major axis of ∼243mas makes it a suitable target for further characterization with high-contrast imaging, in particular to measure its inclination, mass, and spectrum and thus definitely establish its substellar nature. Aims. We aim to further characterize the orbit, atmosphere, and physical nature of HD 72946B. Methods. We present high-contrast imaging data in the near-infrared with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. We also use proper motion measurements of the star from HIPPARCOS and Gaia. Results. The SPHERE data reveal a point source with a contrast of ∼9mag at a projected separation of ∼235mas. No other point sources are detected in the field of view. By jointly fitting the RV, imaging, and proper motion data, we constrain all the orbital parameters of HD 72946B and assess a dynamical mass of 72.4±1.6MJ and a semi-major axis of 6.456.45+0.08–0.07au. Empirical comparison of its SPHERE spectrum to template dwarfs indicates a spectral type of L5.0±1.5. The J-H3 color is close to the expectations of the DUSTY models and suggests a cloudy atmosphere. Comparison with atmospheric models of the spectrophotometry suggests an effective temperature of ∼1700K. The bolometric luminosity (log(L/L)=-4.11±0.10dex) and dynamical mass of HD 72946B are more compatible with evolutionary models for an age range of ∼0.9-3Gyr. The formation mechanism of the companion is currently unclear as the object appears slightly away from the bulk of model predictions. HD 72946B is currently the closest benchmark brown dwarf companion to a solar-type star with imaging, RV, and proper motion measurements.

Abstract Copyright: © ESO 2019

Journal keyword(s): brown dwarfs - methods: data analysis - stars: individual: HD 72946 - planets and satellites: dynamical evolution and stability - techniques: high angular resolution - techniques: image processing

Simbad objects: 35

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Number of rows : 35

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 HD 4113C BD* 00 43 12.59 -37 58 57.4           T9 14 0
2 HD 4747b Pl? 00 49 26.7612113944 -23 12 44.865754071           ~ 21 0
3 V* GU Psc B BD* 01 12 36.53808 +17 04 29.9424           T3.5 52 0
4 NGC 752 OpC 01 57 41 +37 47.1           ~ 558 0
5 HD 19467B BD* 03 07 18.48 -13 45 43.3           T5.5+1 24 0
6 2MASS J03552337+1133437 BD* 03 55 23.3772215371 +11 33 43.796763263           L5gamma 92 0
7 Cl Melotte 25 OpC 04 26 54.00 +15 52 00.0           ~ 2756 0
8 * 51 Eri b Pl 04 37 36.1323118067 -02 28 24.778826936           ~ 109 0
9 * bet Pic b Pl 05 47 17.0876901 -51 03 59.441135           ~ 381 1
10 HD 42581B BD* 06 10 34.80 -21 52 00.0           T6.5 467 0
11 2MASS J08354678+0635294 NIR 08 35 46.78008 +06 35 29.4720           ~ 1 0
12 HD 72945 SB* 08 35 50.9773580356 +06 37 12.780931161 6.55     5.6   F8V 115 0
13 HD 72946 PM* 08 35 51.2665915520 +06 37 21.970611710 8.23     6.7   G8-V 111 0
14 HD 72946b Pl? 08 35 51.2665915520 +06 37 21.970611710           ~ 4 0
15 HD 76346 ** 08 53 03.7788614388 -56 38 58.137676320   5.982 5.998     A0V 49 0
16 TWA 27B BD* 12 07 33.50 -39 32 54.4           L3 250 0
17 HD 106906B BD* 12 17 52.61 -55 58 26.6           L2.5 60 0
18 NAME VHS J1256-1257B BD* 12 56 01.83264 -12 57 27.6912           L8.0 39 0
19 * e Vir b Pl 13 16 46.5161591991 +09 25 26.967205938           ~ 86 1
20 HD 115470b Pl? 13 18 05.1042056946 -44 03 19.376995020           ~ 6 0
21 HD 116434C BD* 13 24 36.13 -51 30 16.7           L5-7 38 1
22 HD 143567B LM* 16 01 55.65696 -21 58 53.0076           M8 28 0
23 NAME UScoCTIO 108B BD? 16 05 54.09504 -18 18 48.8592           ~ 46 0
24 RX J1609.5-2105B LM* 16 09 30.377 -21 04 56.97           ~ 100 0
25 NAME GSC 06214-00210B LM* 16 21 54.678 -20 43 11.33           ~ 64 0
26 2MASS J16471580+5632057 BD* 16 47 15.80544 +56 32 05.7264           L9pec 26 0
27 * alf Lyr dS* 18 36 56.33635 +38 47 01.2802 0.03 0.03 0.03 0.07 0.10 A0Va 2544 0
28 HD 182488B BD* 19 23 34.0126 +33 13 19.078           T9 56 0
29 * 15 Sge PM* 20 04 06.2209062328 +17 04 12.677429047   6.390 5.788 5.4   G0V 349 0
30 * zet Del B BD* 20 35 19.05 +14 40 15.6           L5 12 0
31 V* HN Peg B BD* 21 44 28.47168 +14 46 07.7988           T2.5 108 0
32 HD 218396e Pl 23 07 28.7156905667 +21 08 03.302133882           ~ 145 1
33 HD 218396b Pl 23 07 28.7156905667 +21 08 03.302133882           ~ 219 1
34 HD 218396c Pl 23 07 28.7156905667 +21 08 03.302133882           ~ 207 1
35 HD 218396d Pl 23 07 28.7156905667 +21 08 03.302133882           ~ 190 1

    Equat.    Gal    SGal    Ecl

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2021.05.06-19:55:09

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