1 Camelopardalis

Lore & Background

The 1 Camelopardalis system consists of at least two stars: 1 Camelopardalis A, a hot massive giant that has evolved away from the main sequence, and 1 Camelopardalis B, an early B class subgiant located about 10 arcseconds away. An additional star was discovered using the CHARA array, with a mean separation of 26.16 milliarcseconds from 1 Camelopardalis A. An 11th magnitude star 150 arcseconds away was once considered a possible member of a triple system, but Gaia observations show it to be an unrelated background object.

The variability of 1 Camelopardalis was first reported in 1982, though some subsequent studies failed to confirm it. Its brightness was convincingly shown to be variable when Hipparcos data was analyzed, and it received its variable star designation, DL Camelopardalis, in 1999. 1 Camelopardalis A is a variable star with a small amplitude, a likely period of 0.22132 days, and is thought to be a β Cephei variable or slowly pulsating B-type star. Hipparcos photometry shows an amplitude of 0.035 magnitudes. It has one of the highest known rotational velocities.

The system is part of the Camelopardalis OB1 stellar association, which is 820 pc away. 1 Camelopardalis A was once reported to be a double-lined spectroscopic binary with an orbital period of 1.31 days, but this has not been confirmed since.

Reader's Guide

1 Camelopardalis (DL Camelopardalis) holds significance as a variable star within the Camelopardalis OB1 association, contributing to the study of massive star evolution and pulsation. Its classification as a likely β Cephei variable or slowly pulsating B-type star places it among hot, massive stars that exhibit small-amplitude brightness variations driven by internal pressure or gravity modes. The system's high rotational velocity is among the highest known, offering insights into the rotational dynamics of evolved giant stars. The unresolved status of the previously reported 1.31-day spectroscopic binary adds an element of uncertainty that invites further investigation. The discovery of an additional component via the CHARA array at a very small separation highlights the complexity of the system and the value of high-resolution interferometry in resolving close stellar companions. The rejection of the 11th magnitude star as a background object by Gaia data underscores the importance of precise astrometry in confirming stellar associations. Overall, 1 Camelopardalis serves as a case study in the challenges of confirming variability and multiplicity in distant, hot stars, and its membership in the OB association ties it to a larger region of star formation and massive stellar content.