Iota Crateris

Lore & Background

The primary star, component A, is an F-type main sequence star of class F6.5 V, generating energy through hydrogen fusion in its core. It is about 4.45 billion years old and has 1.19 times the mass of the Sun, radiating at an effective temperature of 6,230 K. The close companion, component B, is a red dwarf with a probable classification of M3, though its mass estimate of 0.57 solar masses would be more consistent with an M0 class star. As of 2014, this magnitude 11.0 star had an angular separation of 1.10 arcseconds at a position angle of 248°, corresponding to a projected separation of at least 25 AU. The system also includes a white dwarf, component C, which is at the same distance and shares a common proper motion with the other two stars; it has the separate designation UCAC4 384-059519.

Reader's Guide

Iota Crateris is significant as a triple system that includes an astrometric binary with an estimated orbital period of roughly 79,000 years, one of the longest known among nearby stars. The system gained wider attention in 2023 when a narrowband radio signal of interest, designated MLc6, was identified in archival 2016 observations from the Breakthrough Listen program. The signal was found at a frequency of 1435.940 MHz with a Doppler drift rate of −0.18 Hz s⁻¹ and a signal-to-noise ratio of approximately 40, and was one of eight candidate signals from a survey of 820 nearby stars. Follow-up observations in May 2022 did not recover the signal, indicating it is not persistent. An independent analysis could not process the signal because its drift rate exceeded the operational range of the search algorithm when applied to available reduced data products; the authors noted it might have been recoverable had the original raw voltage data been preserved. Of the five candidate signals from the same survey that their pipeline did process, all were identified as radio frequency interference. The system thus remains a subject of interest in the search for technosignatures, though the signal has not been confirmed as extraterrestrial in origin.

Did You Know?

• The primary star is an F6.5 V main-sequence star with an effective temperature of 6,230 K.
• A candidate narrowband radio signal, MLc6, was identified in 2016 observations but was not recovered in 2022 follow-up observations.
• The system includes a white dwarf component, UCAC4 384-059519, that shares common proper motion with the other two stars.