Journal
ASTRONOMY & ASTROPHYSICS
Volume 562, Issue -, Pages -Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201322119
Keywords
instrumentation: adaptive optics; techniques: photometric; planetary systems; stars: individual: kappa Andromedae
Categories
Funding
- NASA
- NSF [1009314, 1009203, 1008440]
- W.M. Keck Foundation
- NASA Origins of Solar Systems Program [NNX13AJ17G]
- JSPS [PD: 24 110]
- French Agence Nationale de la Recherche [ANR10-BLANC0504-01]
- Programme National de Physique Stellaire (PNPS) of CNRS (INSU)
- European Research Council under the European Community [247060]
- Lyon Institute of Origins [ANR-10-LABX-66]
- STFC [ST/J001651/1, ST/K001515/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/K001515/1, ST/J001651/1] Funding Source: researchfish
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [1009203, 1008440] Funding Source: National Science Foundation
- Grants-in-Aid for Scientific Research [23103004, 23103002, 22000005, 23740151, 23340051] Funding Source: KAKEN
- NASA [472992, NNX13AJ17G] Funding Source: Federal RePORTER
Ask authors/readers for more resources
Context. We previously reported the direct detection of a low-mass companion at a projected separation of 55 +/- 2 AU around the B9-type star kappa Andromedae. The properties of the system (mass ratio, separation) make it a benchmark for understanding the formation and evolution of gas giant planets and brown dwarfs on wide orbits. Aims. We present new angular differential imaging (ADI) images of the system at 2.146 (K-s), 3.776 (L'), 4.052 (NB_4.05), and 4.78 mu m (M') obtained with Keck/NIRC2 and LBTI/LMIRCam, as well as more accurate near-infrared photometry of the star with the MIMIR instrument. We aim to determine the near-infrared spectral energy distribution of the companion and use it to characterize the object. Methods. We used analysis methods adapted to ADI to extract the companion flux. We compared the photometry of the object to reference young, and old objects and to a set of seven PHOENIX-based atmospheric models of cool objects accounting for the formation of dust. We used evolutionary models to derive mass estimates considering a wide range of plausible initial conditions. Finally, we used dedicated formation models to discuss the possible origin of the companion. Results. We derive a more accurate J = 15.86 +/- 0.21, H = 14.95 +/- 0.13, K-s = 14.32 +/- 0.09 mag for kappa And b. We detect the companion in all our high-contrast observations. We confirm previous contrasts obtained at K-s and L' band. We derive NB_4.05 = 13.0 +/- 0.2, and M' = 13.3 +/- 0.3 mag and estimate log(10)(L/L-circle dot) = -3.76 +/- 0.06. Atmospheric models yield T-eff = 1900(-200)(+100) K. They do not set any constraint on the surface gravity. Hot-start evolutionary models predict masses of 14(-2)(+25) M-Jup based on the luminosity and temperature estimates, and when considering a conservative age range for the system (30(-10)(+120) Myr), warm-start evolutionary tracks constrain the mass to M >= 10 M-Jup. Conclusions. The mass of kappa Andromedae b mostly falls in the brown-dwarf regime, owing to remaining uncertainties in age and in mass-luminosity models. According to the formation models, disk instability in a primordial disk may account for the position and a wide range of plausible masses of kappa And b.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available