A team of astronomers, led by Fengqiu Adam Dong of Peking University, has unveiled one of the most remarkable discoveries in astrophysics. They have discovered in it CHIME J1634+44, a long-period radio transient (LPT). This weird cosmic beast of a star pulses every 841 seconds. It has a secondary pulse period of ~4,206 seconds, indicating that it may display binary activity. In October 2022, the research team captured that very first burst from CHIME J1634+44. Next, through continuous monitoring, they documented reactivation events during February and November 2023.
What makes CHIME J1634+44 particularly special are its long pulse periods. It is the first known LPT that displays circular polarization. A forthcoming paper, appearing soon on the pre-print server arXiv on July 7, 2025, describes this incredible find in more detail. It sheds light on the rare properties of the celestial phenomenon and discusses its possible implications for better understanding radio transients. The study published as Dong et al discusses the findings of the author of the DAO.
Characteristics of CHIME J1634+44
Among all these interesting black holes in our cosmic zoo, CHIME J1634+44 is special for its extraordinary characteristics. Its long primary pulse period of 841 seconds puts it into the long-period category of radio transients. At the same time, the secondary period of ~4206 sec suggests possible interaction with a second celestial body, showing signs of binary behavior.
Together, those observations strongly suggest that CHIME J1634+44 is a very fast spin-up. Its spin period is increasing with a phenomenal negative period derivative of ∼−9.03 s/s. This spin-up effect leads to tantalizing questions about what is causing these changes in rotation speed.
While the origin of such bursts is still unclear, researchers have successfully detected 89 unique bursts from CHIME J1634+44 over the course of about 4.5 years. This rich dataset will offer unprecedented data to scientists seeking to understand the nature and behavior of LPTs.
Implications for Astrophysics
The importance of CHIME J1634+44 goes beyond its strange appearance. As exciting as the find is, it offers a fertile opportunity for researchers to better illustrate their theories about LPT emissions.
“CHIME J1634+44 will serve as an important test bed for LPT emission theories and is unique among the array of known transient source emitters,” – scientists involved in the study.
This announcement highlights the deeper consequences that CHIME J1634+44 can have on research direction in the field going forward. Understanding the properties and behavior of this newly discovered LPT has the potential to transform astrophysical research. That will improve human understanding of incredible cosmic phenomena too.
Methodology Behind Discovery
The discovery process for CHIME J1634+44 was atypical due to in-depth monitoring as part of the CHIME/FRB single-pulse pulsar survey. As such, the team used fairly stringent trigger criteria based on dispersion measures (DM). This strategy allowed them to pinpoint sources they knew for sure would be during the Milky Way galaxy, based on theoretical models.
“CHIME J1634+44 was discovered in the CHIME/FRB single-pulse pulsar survey, where we are using the CHIME/FRB trigger criteria for all sources with a dispersion measure (DM) low enough to be considered inside the Milky Way galaxy according to both the NE2001 and the YMW16 DM models,” – researchers detailed in their findings.
This methodical process allowed the chase team astronomers to home in on CHIME J1634+44 with surgical precision. They just re-affirmed its determination as an LPT and instituted regular monitoring observations to track its chronicity.