2023ApJ...956...99B

Query : 2023ApJ...956...99B

2023ApJ...956...99B - Astrophys. J., 956, 99 (2023/October-3)

VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B.

BALMER W.O., PUEYO L., STOLKER T., REGGIANI H., MAIRE A.-L., LACOUR S., MOLLIERE P., NOWAK M., SING D., POURRE N., BLUNT S., WANG J.J., RICKMAN E., KAMMERER J., HENNING T., WARD-DUONG K., ABUTER R., AMORIM A., ASENSIO-TORRES R., BENISTY M., BERGER J.-P., BEUST H., BOCCALETTI A., BOHN A., BONNEFOY M., BONNET H., BOURDAROT G., BRANDNER W., CANTALLOUBE F., CASELLI P., CHARNAY B., CHAUVIN G., CHAVEZ A., CHOQUET E., CHRISTIAENS V., CLENET Y., COUDE DU FORESTO V., CRIDLAND A., DEMBET R., DEXTER J., DRESCHER A., DUVERT G., ECKART A., EISENHAUER F., GAO F., GARCIA P., GARCIA LOPEZ R., GENDRON E., GENZEL R., GILLESSEN S., GIRARD J.H., HAUBOIS X., HEISSEL G., HINKLEY S., HIPPLER S., HORROBIN M., HOULLE M., HUBERT Z., JOCOU L., KEPPLER M., KERVELLA P., KREIDBERG L., LAGRANGE A.-M., LAPEYRERE V., LE BOUQUIN J.-B., LENA P., LUTZ D., MONNIER J.D., MOUILLET D., NASEDKIN E., OTT T., OTTEN G.P.P.L., PALADINI C., PAUMARD T., PERRAUT K., PERRIN G., PFUHL O., RAMEAU J., RODET L., ROUSSET G., RUSTAMKULOV Z., SHANGGUAN J., SHIMIZU T., STADLER J., STRAUB O., STRAUBMEIER C., STURM E., TACCONI L.J., VAN DISHOECK E.F., VIGAN A., VINCENT F., VON FELLENBERG S.D., WIDMANN F., WIEPRECHT E., WIEZORREK E., WINTERHALDER T., WOILLEZ J., YAZICI S., YOUNG A. (The ExoGRAVITY Collaboration) (The GRAVITY Collaboration)

Abstract (from CDS):

Tension remains between the observed and modeled properties of substellar objects, but objects in binary orbits, with known dynamical masses, can provide a way forward. HD 72946 B is a recently imaged brown dwarf companion to a nearby, solar-type star. We achieve ∼100 μas relative astrometry of HD 72946 B in the K band using VLTI/GRAVITY, unprecedented for a benchmark brown dwarf. We fit an ensemble of measurements of the orbit using orbitize! and derive a strong dynamical mass constraint MB = 69.5 ± 0.5 MJup assuming a strong prior on the host star mass MA = 0.97 ± 0.01 M⊙ from an updated stellar analysis. We fit the spectrum of the companion to a grid of self-consistent BT-Settl-CIFIST model atmospheres, and perform atmospheric retrievals using petitRADTRANS. A dynamical mass prior only marginally influences the sampled distribution of effective temperature, but has a large influence on the surface gravity and radius, as expected. The dynamical mass alone does not strongly influence retrieved pressure-temperature or cloud parameters within our current retrieval setup. Independently of the cloud prescription and prior assumptions, we find agreement within ±2σ between the C/O of the host (0.52 ± 0.05) and brown dwarf (0.43-0.63), as expected from a molecular cloud collapse formation scenario, but our retrieved metallicities are implausibly high (0.6-0.8) in light of the excellent agreement of the data with the solar-abundance model grid. Future work on our retrieval framework will seek to resolve this tension. Additional study of low surface gravity objects is necessary to assess the influence of a dynamical mass prior on atmospheric analysis.

Abstract Copyright: © 2023. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Brown dwarfs - L dwarfs - Interferometry - Long baseline interferometry - Optical interferometry - Orbit determination - Exoplanet atmospheres - Stellar atmospheres

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 HD 4747 SB* 00 49 26.7604733944 -23 12 44.868742449 8.244 7.927 7.155 6.732 6.344 G8/K0V 226 0
2 2MASS J05002100+0330501 BD* 05 00 21.0116447403 +03 30 50.081620281           L4pec 51 0
3 * bet Pic b Pl 05 47 17.0876901 -51 03 59.441135           ~ 627 1
4 HD 72945 SB* 08 35 50.9775809112 +06 37 12.769503348 6.55 6.43 5.92     F8V 128 0
5 HD 72946 ** 08 35 51.2666658240 +06 37 21.954760284 8.23 7.77 7.08     G8-V 147 1
6 2MASS J14162408+1348263 BD* 14 16 24.0739698960 +13 48 26.193281184           L5 88 1
7 * 15 Sge B BD* 20 04 06.2 +17 04 13           L4-5 71 0
8 * 15 Sge PM* 20 04 06.2207683221 +17 04 12.676556401   6.390 5.788 5.4   G0V 420 0
9 2MASSW J2224438-015852 BD* 22 24 43.8544128559 -01 58 53.284975671           L4.5V 150 0
10 HD 218396e Pl 23 07 28.7157209544 +21 08 03.310767492           ~ 255 1

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