A 2-d orbital period for a redback millisecond pulsar candidate in the globular cluster NGC 6397

Manuel Pichardo Marcano, Liliana E. Rivera Sandoval, Thomas J. MacCarone, Yue Zhao, Craig O. Heinke

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We report optical modulation of the companion to the X-ray source U18 in the globular cluster NGC 6397. U18, with combined evidence from radio and X-ray measurements, is a strong candidate as the second redback in this cluster, initially missed in pulsar searches. This object is a bright variable star with an anomalous red colour and optical variability (∼0.2 mag in amplitude) with a periodicity ∼1.96 d that can be interpreted as the orbital period. This value corresponds to the longest orbital period for known redback candidates and confirmed systems in Galactic globular clusters and one of the few with a period longer than 1 d.

Original languageEnglish
Pages (from-to)L51-L55
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume503
Issue number1
DOIs
StatePublished - May 1 2021

Keywords

  • X-rays: binaries pulsars
  • globular clusters: general
  • globular clusters: individual (NGC 6397)

Fingerprint Dive into the research topics of 'A 2-d orbital period for a redback millisecond pulsar candidate in the globular cluster NGC 6397'. Together they form a unique fingerprint.

Cite this