MKT J170456.2−482100: The first transient discovered by MeerKAT

L. N. Driessen, I. McDonald, D. A.H. Buckley, M. Caleb, E. J. Kotze, S. B. Potter, K. M. Rajwade, A. Rowlinson, B. W. Stappers, E. Tremou, P. A. Woudt, R. P. Fender, R. Armstrong, P. Groot, I. Heywood, A. Horesh, A. J. van der Horst, E. Koerding, V. A. McBride, J. C.A. Miller-JonesK. P. Mooley, R. A.M.J. Wijers

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22 Scopus citations


We report the discovery of the first transient with MeerKAT, MKT J170456.2−482100, discovered in ThunderKAT images of the low-mass X-ray binary GX339−4. MKT J170456.2−482100 is variable in the radio, reaching a maximum flux density of 0.71 ± 0.11 mJy on 2019 October 12, and is undetected in 15 out of 48 ThunderKAT epochs. MKT J170456.2−482100 is coincident with the chromospherically active K-type sub-giant TYC 8332-2529-1, and ∼ 18 yr of archival optical photometry of the star shows that it varies with a period of 21.25 ± 0.04 d. The shape and phase of the optical light curve changes over time, and we detect both X-ray and UV emission at the position of MKT J170456.2−482100, which may indicate that TYC 8332-2529-1 has large star spots. Spectroscopic analysis shows that TYC 8332-2529-1 is in a binary, and has a line-of-sight radial velocity amplitude of 43 km s−1. We also observe a spectral feature in antiphase with the K-type sub-giant, with a line-of-sight radial velocity amplitude of ∼ 12 ± 10 km s−1, whose origins cannot currently be explained. Further observations and investigation are required to determine the nature of the MKT J170456.2−482100 system.

Original languageAmerican English
Pages (from-to)560-575
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - 1 Jan 2020

Bibliographical note

Publisher Copyright:
© 2019 The Author(s)


  • Binaries: spectroscopic
  • Stars: activity
  • Stars: flare
  • Stars: peculiar


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