An active, asynchronous companion to a redback millisecond pulsar

Journal Article · Sat Dec 10 04:00:00 EST 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/833/1/L12· OSTI ID:22868362

Staden, André D. van ^[1]; Antoniadis, John ^[2]

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1. 11 Sonopstreet, Bredasdorp, Western Cape 7280 (South Africa)
2. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M6P 2R7 (Canada)

PSR J1723−2837 is a “redback” millisecond pulsar (MSP) with a low-mass companion in a 14.8 hr orbit. The system’s properties closely resemble those of “transitional” MSPs that alternate between spin-down and accretion-powered states. In this Letter, we report on long-term photometry of the 15.5 mag companion to the pulsar. We use our data to illustrate that the star experiences sporadic activity, which we attribute to starspots. We also find that the companion is not tidally locked and infer P{sub s}/P{sub b}=0.9974(7) for the ratio between the rotational and orbital periods. Finally, we place constraints on various parameters, including the irradiation efficiency and pulsar mass. We discuss similarities with other redback MSPs and conclude that starspots may provide the most likely explanation for the often seen irregular and asymmetric optical light curves.

• OSTI ID: 22868362
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 833; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASYMMETRY
DIAGRAMS
IRRADIATION
MASS
ORBITS
PHOTOMETRY
PULSARS
STARSPOTS
VISIBLE RADIATION