Fortnightly Fluctuations in the O-C Diagram of CS 1246

Abstract

Dominated by a single, large-amplitude pulsation mode, the rapidly-pulsating hot subdwarf B star CS 1246 is a prime candidate for a long-term O-C diagram study. We collected nearly 400 hours of photometry with the PROMPT telescopes over a time span of 14 months to begin looking for secular variations in the pulse timings. Interestingly, the O-C diagram is dominated by a strong sinusoidal pattern with a period of 14.1 days and an amplitude of 10.7 light-seconds. Underneath this sine wave is a secular trend implying a decrease in the 371.7-s pulsational period of Pdot = -1.9 x 10^-11, which we attribute to the evolution of the star through the H-R diagram. The sinusoidal variation could be produced by the presence of a low-mass companion, with m sin i ~ 0.12 Msun, orbiting the subdwarf B star at a distance of 20 Rsun. An analysis of the combined light curve reveals the presence of a low-amplitude first harmonic to the main pulsation mode.

Accepted for publication in MNRAS. 11 pages, 8 figures, 5 tables

References in corpus (2)

• EXOTIME: searching for planets around pulsating subdwarf B stars
• Structure and evolution of pulsating hot subdwarfs

Cited by in corpus (11)

• Stellar wind models of subluminous hot stars
• Periodic Variations in the O-C Diagrams of Five Pulsation Frequencies of the DB White Dwarf EC 20058-5234
• Radial Velocity Confirmation of a Binary Detected from Pulse Timings
• The sdB pulsating star V391 Peg and its putative giant planet revisited after 13 years of time-series photometric data
• Timing by Stellar Pulsations as an Exoplanet Discovery Method
• Non-Detection of the Putative Substellar Companion to HD 149382
• TESS search for substellar companions through pulsation timing of $\delta$ Scuti stars. I. Discovery of companions around Chang 134 and V393 Car
• Skynet Algorithm for Single-Dish Radio Mapping I: Contaminant-Cleaning, Mapping, and Photometering Small-Scale Structures
• The EXOTIME project: Signals in the $O-C$ diagrams of the rapidly pulsating subdwarfs DW Lyn, V1636 Ori, QQ Vir, and V541 Hya
• Anomalous Orbital Characteristics of the AQ Col (EC 05217-3914) System
• Spectroscopic follow-up of hot subdwarf variables found in ZTF -- Atmospheric and fundamental properties of radial-mode sdB pulsators