Finding Subdwarf B stars using Python automation and TESS data

Subdwarf B (sdB) stars are extreme horizontal branch stars with high temperature and gravity. The most promising formation scenarios involve close binary star evolution with three different channels, (a) Common Envelope (CE) channel , which can produce short period (P = 0.1 – 10 d) sdB + white dwarf (WD) or main sequence (MS) binary systems, (b) Roche lobe overflow (RLOF) channel, which results in long period (450 \u3c P \u3c 1400 d) sdb + MS binary systems, and (c) white-dwarf merger channel, which can produce single sdB stars. Unlike other types of stars, sdB types have a myriad of data; however, there is lack of automation code in the RLOF channel due to long-term efforts. This Python program aims to aid these missing areas in sdB binary research by automating the pulsation timing process. This Python program has been proven to shorten the analysis time down to a couple of minutes and has been tested with the target TIC 273218137 (BPM 36430) for accuracy due to the known binary status of the target. This program will be able to decrease the amount of time needed to analyze data and increase the number of discoveries that are able to be made

Utilizing the O-C Method to Determine Third-Body Existence in Eclipsing Binary Systems

Previous studies on the subject of eclipsing binaries (EBs) within the Kepler field have been adequately determined the period, distance, and other stellar parameters of these systems (Borkovits, et al. 2015). Additionally, with the use of Observed-minus-Calculated (O-C) plots, variation in the timing of timing of eclipses can be easily detected. The eclipse timing shifts may be caused by dynamical effects or by light-travel time effects (LTTE) caused by the existence of a third body. The following research was conducted on ten binaries within the Kepler “K2” Campaign 5 field whose light curves (LCs) showed evidence of eclipses with periods shorter than ten days. The timings of the eclipses were then investigated using the O-C method to search for variations and, if so, to deduce the cause of such variations and to determine the parameters of the binary

Gyrochronology of Wide Binaries in the Kepler K2 Campaign 5 Field

We are determining rotation periods for an ensemble of over 100 wide non-interacting binary stars in the K2 Campaign 5 field that contain two main sequence dwarfs, as well as a smaller sample containing at least one white dwarf component. Observations of such coeval pairs provide the basis for our new investigation of rotation-based age determinations. Such “gyrochronology” ages can achieve a precision that exceeds most other current method of stellar age determination. Here we present a status report on our analysis of the light curves extracted from the K2 Campaign 5 field

Gyrochronology of Wide Binaries in the Kepler K2 Fields

Gyrochronology is the method of determining a stars age based on its rotation period and mass. A cool main sequence star loses it\u27s angular momentum as it ages, so the rotation rate slows down. Gyrochronology has been tested on star clusters in previous studies and now we are applying the theory to binary stars. Components of a binary should be the same age, so Gyrochronology should return the same age for both stars in binary systems. We examined the rotation periods for 290 wide binary main sequence stars in the Kepler K2 fields. These observations are part of a continuing investigation of Gyrochronology. Using the determined rotation periods and color index (a proxy for mass), we estimated ages for ~20 binary pairs. Presented here is a status report on our analysis of data from the K2 and the calculated ages of the studied binaries

An Additional Pulsating Mode (7.35 mHz) and Pulsations Timing Variations of PG 1613+426

We present the detection of an additional pulsation mode (7.35 mHz) of a subdwarf B star, PG 1613+426, and periodic Observed minus Calculated (O-C) variations for two existing pulsations. PG 1613+426 is near the hot end of the sdB instability strip. One pulsation mode (6.94 mHz) was detected so far by Bonanno et al. (2002) and another pulsation mode candidate (7.05 mHz) was proposed with a confidence level above 90% by Kuassivi and Ferlet (2005). To constrain sdB star evolutional scenarios, this star was monitored in 2010, 2011, 2015, and 2017 as a part of a project for finding companions to sdB stars using the pulsation timing method. The photometric analysis of those data shows an additional 7.35 mHz pulsation mode as well as the previously detected 6.93 mHz mode. However the 7.05 mHz mode was not detected. Nightly amplitude changes of 7.35 mHz mode were observed in the 2011 data, however the 2017 data did not show nightly amplitude shifts. O-C variations were detected in both 6.93 mHz and 7.35 mHz pulsations, indicating that PG 1613+426 may have a low mass companion star. However, more observations are needed to confirm it