2018A&A...620A.116G

Query : 2018A&A...620A.116G

2018A&A...620A.116G - Astronomy and Astrophysics, volume 620A, 116-116 (2018/12-1)

Multiple star systems in the Orion nebula.

GRAVITY COLLABORATION, KARL M., PFUHL O., EISENHAUER F., GENZEL R., GRELLMANN R., HABIBI M., ABUTER R., ACCARDO M., AMORIM A., ANUGU N., AVILA G., BENISTY M., BERGER J.-P., BLIND N., BONNET H., BOURGET P., BRANDNER W., BRAST R., BURON A., CARATTI O GARATTI A., CHAPRON F., CLENET Y., COLLIN C., COUDE DU FORESTO V., DE WIT W.-J., DE ZEEUW T., DEEN C., DELPLANCKE-STROBELE F., DEMBET R., DERIE F., DEXTER J., DUVERT G., EBERT M., ECKART A., ESSELBORN M., FEDOU P., FINGER G., GARCIA P., GARCIA DABO C.E., GARCIA LOPEZ R., GAO F., GENDRON E., GILLESSEN S., GONTE F., GORDO P., GROZINGER U., GUAJARDO P., GUIEU S., HAGUENAUER P., HANS O., HAUBOIS X., HAUG M., HAUSSMANN F., HENNING T., HIPPLER S., HORROBIN M., HUBER A., HUBERT Z., HUBIN N., JAKOB G., JOCHUM L., JOCOU L., KAUFER A., KELLNER S., KENDREW S., KERN L., KERVELLA P., KIEKEBUSCH M., KLEIN R., KOHLER R., KOLB J., KULAS M., LACOUR S., LAPEYRERE V., LAZAREFF B., LE BOUQUIN J.-B., LENA P., LENZEN R., LEVEQUE S., LIN C.-C., LIPPA M., MAGNARD Y., MEHRGAN L., MERAND A., MOULIN T., MULLER E., MULLER F., NEUMANN U., OBERTI S., OTT T., PALLANCA L., PANDURO J., PASQUINI L., PAUMARD T., PERCHERON I., PERRAUT K., PERRIN G., PFLUGER A., DUC T.P., PLEWA P.M., POPOVIC D., RABIEN S., RAMIREZ A., RAMOS J., RAU C., RIQUELME M., RODRIGUEZ-COIRA G., ROHLOFF R.-R., ROSALES A., ROUSSET G., SANCHEZ-BERMUDEZ J., SCHEITHAUER S., SCHOLLER M., SCHUHLER N., SPYROMILIO J., STRAUB O., STRAUBMEIER C., STURM E., SUAREZ M., TRISTRAM K.R.W., VENTURA N., VINCENT F., WAISBERG I., WANK I., WIDMANN F., WIEPRECHT E., WIEST M., WIEZORREK E., WITTKOWSKI M., WOILLEZ J., WOLFF B., YAZICI S., ZIEGLER D. and ZINS G.

Abstract (from CDS):

This work presents an interferometric study of the massive-binary fraction in the Orion Trapezium cluster with the recently comissioned GRAVITY instrument. We observed a total of 16 stars of mainly OB spectral type. We find three previously unknown companions for θ1 Ori B, θ2 Ori B, and θ2 Ori C. We determined a separation for the previously suspected companion of NU Ori. We confirm four companions for θ1 Ori A, θ1 Ori C, θ1 Ori D, and θ2 Ori A, all with substantially improved astrometry and photometric mass estimates. We refined the orbit of the eccentric high-mass binary θ1 Ori C and we are able to derive a new orbit for θ1 Ori D. We find a system mass of 21.7M☉ and a period of 53-days. Together with other previously detected companions seen in spectroscopy or direct imaging, eleven of the 16 high-mass stars are multiple systems. We obtain a total number of 22 companions with separations up to 600 AU. The companion fraction of the early B and O stars in our sample is about two, significantly higher than in earlier studies of mostly OB associations. The separation distribution hints toward a bimodality. Such a bimodality has been previously found in A stars, but rarely in OB binaries, which up to this point have been assumed to be mostly compact with a tail of wider companions. We also do not find a substantial population of equal-mass binaries. The observed distribution of mass ratios declines steeply with mass, and like the direct star counts, indicates that our companions follow a standard power law initial mass function. Again, this is in contrast to earlier findings of flat mass ratio distributions in OB associations. We excluded collision as a dominant formation mechanism but find no clear preference for core accretion or competitive accretion.

Abstract Copyright: © ESO 2018

Journal keyword(s): techniques: interferometric - astrometry - celestial mechanics - binaries: close - binaries: general - stars: massive

Simbad objects: 19

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Number of rows : 19
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2330 0
2 HD 36982 Or* 05 35 09.8363878512 -05 27 53.216296776 8.00 8.58 8.46     B2V 208 0
3 * tet01 Ori E SB* 05 35 15.7721814864 -05 23 09.889316700           G2IV 97 0
4 TCC 43 * 05 35 15.80180 -05 23 11.8906           ~ 19 0
5 * tet01 Ori A Ae* 05 35 15.8254015008 -05 23 14.334699480 5.87 6.75 6.73 6.42 6.21 B0V 485 1
6 TCC 59 Y*O 05 35 16.10855 -05 23 14.2457           ~ 29 0
7 * tet01 Ori B EB* 05 35 16.1339860056 -05 23 06.784444248 7.71 8.20 7.96     B1V 367 2
8 * tet01 Ori C SB* 05 35 16.4662967280 -05 23 22.921811880 4.20 5.15 5.13 4.91 4.73 O7Vp 1404 1
9 NAME Ori Trapezium OpC 05 35 16.5 -05 23 14           ~ 1619 1
10 * tet01 Ori F Em* 05 35 16.7270624568 -05 23 25.197757584 9.928 10.075 10.122   9.652 B8 43 0
11 M 42 HII 05 35 17 -05 23.4           ~ 4073 0
12 * tet01 Ori D Y*O 05 35 17.2574479992 -05 23 16.570738104 6.08 6.79 6.70 6.40 6.20 B1.5Vp 328 0
13 * tet02 Ori A SB* 05 35 22.9012398264 -05 24 57.832632108 5.37 6.30 6.39 6.30 6.35 O9.5IVp 543 0
14 * tet02 Ori B Y*O 05 35 26.4007537560 -05 25 00.793767576 5.36 6.29 6.38 6.29 11.050 B0.7V 193 0
15 HD 37061 Or* 05 35 31.3649044920 -05 16 02.582064192 6.44 7.09 6.83     O9.5V 355 0
16 * tet02 Ori C Or* 05 35 31.4311124640 -05 25 16.371705000   7.80 8.24     B4V 129 1
17 Brun 862 s*r 05 35 47.0099803752 -05 17 56.964353604   16.093 13.728   8.626 K3-M0I 24 0
18 HD 37115 Be* 05 35 54.078288 -05 37 42.31308 6.45 8.88 8.77 8.07   B7Ve 102 0
19 HD 37150 * 05 36 15.0278258688 -05 38 52.514534220 5.52 6.34 6.51     B3III/IV 116 0

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