2024AJ....167...64B

Query : 2024AJ....167...64B

2024AJ....167...64B - Astron. J., 167, 64 (2024/February-0)

VLTI/GRAVITY Provides Evidence the Young, Substellar Companion HD 136164 Ab Formed Like a “Failed Star”.

BALMER W.O., PUEYO L., LACOUR S., WANG J.J., STOLKER T., KAMMERER J., POURRE N., NOWAK M., RICKMAN E., BLUNT S., SIVARAMAKRISHNAN A., SING D., WAGNER K., MARLEAU G.-D., LAGRANGE A.-M., ABUTER R., AMORIM A., ASENSIO-TORRES R., BERGER J.-P., BEUST H., BOCCALETTI A., BOHN A., BONNEFOY M., BONNET H., BORDONI M.S., 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., DAVIES R., DEMBET R., DRESCHER A., DUVERT G., ECKART A., EISENHAUER F., FORSTER SCHREIBER N.M., GARCIA P., GARCIA LOPEZ R., GENDRON E., GENZEL R., GILLESSEN S., GIRARD J.H., GRANT S., HAUBOIS X., HEISSEL G., HENNING T., HINKLEY S., HIPPLER S., HOULLE M., HUBERT Z., JOCOU L., KEPPLER M., KERVELLA P., KREIDBERG L., KURTOVIC N.T., LAPEYRERE V., LE BOUQUIN J.-B., LENA P., LUTZ D., MAIRE A.-L., MANG F., MERAND A., MOLLIERE P., MORDASINI C., MOUILLET D., NASEDKIN E., OTT T., OTTEN G.P.P.L., PALADINI C., PAUMARD T., PERRAUT K., PERRIN G., PFUHL O., RIBEIRO D.C., RODET L., RUSTAMKULOV Z., SHANGGUAN J., SHIMIZU T., STRAUBMEIER C., STURM E., TACCONI L.J., VIGAN A., VINCENT F., WARD-DUONG K., WIDMANN F., WINTERHALDER T., WOILLEZ J., YAZICI S. (The GRAVITY Collaboration)

Abstract (from CDS):

Young, low-mass brown dwarfs orbiting early-type stars, with low mass ratios (q ≲ 0.01), appear to be intrinsically rare and present a formation dilemma: could a handful of these objects be the highest-mass outcomes of “planetary” formation channels (bottom up within a protoplanetary disk), or are they more representative of the lowest-mass “failed binaries” (formed via disk fragmentation or core fragmentation)? Additionally, their orbits can yield model-independent dynamical masses, and when paired with wide wavelength coverage and accurate system age estimates, can constrain evolutionary models in a regime where the models have a wide dispersion depending on the initial conditions. We present new interferometric observations of the 16 Myr substellar companion HD 136164 Ab (HIP 75056 Ab) made with the Very Large Telescope Interferometer (VLTI)/GRAVITY and an updated orbit fit including proper motion measurements from the Hipparcos-Gaia Catalog of Accelerations. We estimate a dynamical mass of 35 ± 10 MJ (q ∼ 0.02), making HD 136164 Ab the youngest substellar companion with a dynamical mass estimate. The new mass and newly constrained orbital eccentricity (e = 0.44 ± 0.03) and separation (22.5 ± 1 au) could indicate that the companion formed via the low-mass tail of the initial mass function. Our atmospheric fit to a SPHINX M-dwarf model grid suggests a subsolar C/O ratio of 0.45 and 3 × solar metallicity, which could indicate formation in a circumstellar disk via disk fragmentation. Either way, the revised mass estimate likely excludes bottom-up formation via core accretion in a circumstellar disk. HD 136164 Ab joins a select group of young substellar objects with dynamical mass estimates; epoch astrometry from future Gaia data releases will constrain the dynamical mass of this crucial object further.

Abstract Copyright: © 2024. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Brown dwarfs - Substellar companion stars - Orbit determination - Orbits

VizieR on-line data: <Available at CDS (J/AJ/167/64): fig4.dat>

Simbad objects: 24

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Number of rows : 24
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 [UT87] 1 PoC 02 57 +20.2           ~ 3 0
2 HD 19467B BD* 03 07 18.48 -13 45 43.3           T5.5+1 57 0
3 * bet Pic b Pl 05 47 17.0876901 -51 03 59.441135           ~ 627 1
4 * bet Pic c Pl 05 47 17.0876901 -51 03 59.441135           ~ 108 0
5 HD 115470 * 13 18 05.1042607440 -44 03 19.380018204   6.77 6.79     B9.5V 45 0
6 HD 115470b Pl? 13 18 05.1042607440 -44 03 19.380018204           ~ 15 0
7 HD 116434 ** 13 24 36.0977360304 -51 30 16.044711840   7.08 6.98   6.87 A2V 95 0
8 HD 116434C BD* 13 24 36.13 -51 30 16.7           L5-7 123 1
9 CD-40 8434b Pl 14 08 10.1545500744 -41 23 52.573291080           ~ 295 0
10 CD-40 8434c Pl 14 08 10.1545500744 -41 23 52.573291080           ~ 240 0
11 HD 136164 * 15 20 13.3930468800 -34 55 31.574157060   7.97 7.76     A2V 36 0
12 HD 136164C LM* 15 20 13.40 -34 55 31.5           M6-L2 6 0
13 HD 136164B * 15 20 13.6323125064 -34 55 27.294983184           ~ 4 0
14 NAME Upper Centaurus Lupus MGr 15 24 -41.9           ~ 567 1
15 NAME Upper Sco-Cen As* 16 15 -24.2           ~ 1497 1
16 HD 149274 * 16 35 13.8392866176 -35 43 28.725611232   6.57 6.64     B9V 32 0
17 HD 149274B LM* 16 35 13.84 -35 43 28.7           M5 5 0
18 * mu.02 Sco bC? 16 52 20.1453198 -38 01 03.125839 2.52 3.343 3.542     B2IV 161 0
19 * mu.02 Sco b Pl? 16 52 20.1453198 -38 01 03.125839           ~ 10 0
20 V* PZ Tel BY* 18 53 05.8735056984 -50 10 49.897437168   9.22 8.342   7.464 G9IV 364 0
21 HD 206893B BD? 21 45 21.9 -12 47 00           ~ 19 0
22 HD 206893 PM* 21 45 21.9052532928 -12 47 00.060804636   7.11 6.67     F5V 143 0
23 HD 206893c Pl 21 45 21.9052532928 -12 47 00.060804636           ~ 35 0
24 HD 218396e Pl 23 07 28.7157209544 +21 08 03.310767492           ~ 255 1

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