Title

Astrometric Monitoring Of The Binary Brown Dwarf Denis-P J1228.2-1547

Keywords

Astrometry; Stars: Binaries: Visual; Stars: Low-mass, brown dwarfs - Stars: Fundamental parameters

Abstract

We present astrometric monitoring data of the binary brown dwarf DENIS-PJ 1228.2-1547. The data have been obtained with the Hubble Space Telescope over a time span of 5.5 yr, and confirm that DENIS-PJ 1228.2-1547 is indeed a common proper motion, i.e., physical, binary. The data cover about l/8th of the binary orbit, indicating art orbital period of ≈45 yr, and a semimajor axis of ≈6.4 AU. A plausible fit of the orbital parameters indicates that both components of the binary are substellar, which is in good agreement with previous mass estimates based on the presence of lithium in the combined spectra of both components. Since the next periastron passage of DENIS-PJ1228.2-1547 is expected for the years 2030 to 2035, longterm astrometric monitoring is required to derive accurate mass estimates for the system and the individual components. The photometry obtained with HST/WFPC2 in the F814W band shows no indication for photometric variability with an amplitude larger than 0.05 mag over a time span of ≈ 1000 days.

Publication Date

12-1-2004

Publication Title

Astronomy and Astrophysics

Volume

428

Issue

1

Number of Pages

205-208

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1051/0004-6361:20041912

Socpus ID

10044287402 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/10044287402

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