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Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring

Mancini, L. and Giacobbe, P. and Littlefair, S. P. and Southworth, J. and Bozza, V. and Damasso, M. and Dominik, M. and Hundertmark, M. and Jørgensen, U. G. and Juncher, D. and Popovas, A. and Rabus, M. and Rahvar, S. and Schmidt, R. W. and Skottfelt, J. and Snodgrass, C. and Sozzetti, A. and Alsubai, K. and Bramich, D. M. and Calchi Novati, S. and Ciceri, S. and D’Ago, G. and Figuera Jaimes, R. and Galianni, P. and Gu, S.-H. and Harpsøe, K. and Haugbølle, T. and Henning, Th. and Hinse, T. C. and Kains, N. and Korhonen, H. and Scarpetta, G. and Starkey, D. and Surdej, J. and Wang, X.-B. and Wertz, O. (2015) Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring. Astronomy and Astrophysics, 584 . Art. No. A104. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20160115-160302885

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Abstract

Context. Photometric monitoring of the variability of brown dwarfs can provide useful information about the structure of clouds in their cold atmospheres.The brown-dwarf binary system Luhman 16AB is an interesting target for such a study, because its components stand at the L/T transition and show high levels of variability. Luhman 16AB is also the third closest system to the solar system, which allows precise astrometric investigations with ground-based facilities. Aims. The aim of the work is to estimate the rotation period and study the astrometric motion of both components. Methods. We have monitored Luhman 16AB over a period of two years with the lucky-imaging camera mounted on the Danish 1.54 m telescope at La Silla, through a special i + z long-pass filter, which allowed us to clearly resolve the two brown dwarfs into single objects. An intense monitoring of the target was also performed over 16 nights, in which we observed a peak-to-peak variability of 0.20 ± 0.02 mag and 0.34 ± 0.02 mag for Luhman 16A and 16B, respectively. Results. We used the 16-night time-series data to estimate the rotation period of the two components. We found that Luhman 16B rotates with a period of 5.1 ± 0.1 h, in very good agreement with previous measurements. For Luhman 16A, we report that it rotates more slowly than its companion, and even though we were not able to get a robust determination, our data indicate a rotation period of roughly 8 h. This implies that the rotation axes of the two components are well aligned and suggests a scenario in which the two objects underwent the same accretion process. The 2-year complete data set was used to study the astrometric motion of Luhman 16AB. We predict a motion of the system that is not consistent with a previous estimate based on two months of monitoring, but cannot confirm or refute the presence of additional planetary-mass bodies in the system.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1051/0004-6361/201526899DOIArticle
http://www.aanda.org/articles/aa/abs/2015/12/aa26899-15/aa26899-15.htmlPublisherArticle
ORCID:
AuthorORCID
Littlefair, S. P.0000-0001-7221-855X
Bozza, V.0000-0003-4590-0136
Dominik, M.0000-0002-3202-0343
Calchi Novati, S.0000-0002-7669-1069
Hinse, T. C.0000-0001-8870-3146
Surdej, J.0000-0002-7005-1976
Wertz, O.0000-0003-3849-2285
Additional Information:© ESO, 2015. Received 5 July 2015 / Accepted 25 October 2015. Based on data collected by MiNDSTEp with the Danish 1.54m telescope at the ESO La Silla Observatory. The operation of the Danish 1.54 m telescope is financed by a grant to UGJ from the Danish Natural Science Research Council (FNU). The reduced light curves presented in this work will be made available at the CDS. J. Southworth acknowledges financial support from the STFC in the form of an Advanced Fellowship. O.W. and J. Surdej acknowledge support from the Communauté française de Belgique – Actions de recherche concertées – Académie Wallonie-Europe. S.H.G. and X.B.W. would like to acknowledge the financial support from the National Natural Science Foundation of China through grants Nos. 10873031 and 11473066. M.H. acknowledges support from the Villum Foundation. We acknowledge the use of the following internet-based resources: the ESO Digitized Sky Survey; the TEPCat catalogue; the SIMBAD data base operated at the CDS, Strasbourg, France; and the arXiv scientific paper preprint service operated by Cornell University.
Funders:
Funding AgencyGrant Number
Danish Natural Science Research Council (FNU)UNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Communauté française de Belgique – Actions de recherche concertées – Académie universitaire Wallonie-EuropeUNSPECIFIED
National Natural Science Foundation of China10873031
National Natural Science Foundation of China11473066
Villum FoundationUNSPECIFIED
Subject Keywords:binaries: visual / brown dwarfs / stars: variables: general / techniques: photometric / techniques: image processing
Record Number:CaltechAUTHORS:20160115-160302885
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160115-160302885
Official Citation:Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring L. Mancini, P. Giacobbe, S. P. Littlefair, J. Southworth, V. Bozza, M. Damasso, M. Dominik, M. Hundertmark, U. G. Jørgensen, D. Juncher, A. Popovas, M. Rabus, S. Rahvar, R. W. Schmidt, J. Skottfelt, C. Snodgrass, A. Sozzetti, K. Alsubai, D. M. Bramich, S. Calchi Novati, S. Ciceri, G. D’Ago, R. Figuera Jaimes, P. Galianni, S.-H. Gu, K. Harpsøe, T. Haugbølle, Th. Henning, T. C. Hinse, N. Kains, H. Korhonen, G. Scarpetta, D. Starkey, J. Surdej, X.-B. WangL. Mancini, P. Giacobbe, S. P. Littlefair, J. Southworth, V. Bozza, M. Damasso, M. Dominik, M. Hundertmark, U. G. Jørgensen, D. Juncher, A. Popovas, M. Rabus, S. Rahvar, R. W. Schmidt, J. Skottfelt, C. Snodgrass, A. Sozzetti, K. Alsubai, D. M. Bramich, S. Calchi Novati, S. Ciceri, G. D’Ago, R. Figuera Jaimes, P. Galianni, S.-H. Gu, K. Harpsøe, T. Haugbølle, Th. Henning, T. C. Hinse, N. Kains, H. Korhonen, G. Scarpetta, D. Starkey, J. Surdej, X.-B. Wang and O. Wertz A&A, 584 (2015) A104 DOI: http://dx.doi.org/10.1051/0004-6361/201526899
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63728
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:19 Jan 2016 19:12
Last Modified:09 Mar 2020 13:19

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