Long Period Variables (LPVs) are Asymptotic Giant Branch stars with periods>100 days. Around one third to half of LPVs display a Long Secondary Period (LSP) that is 5-10 times the length of the main periods. The exact cause of LSPs are unknown, with one potential explanation lying in cross-harmonics caused by the interaction of two simultaneously occurring periods. In this paper, we use the Fourier analysis software VStar to examine the visual range photometric light curves obtained through the American Association of Variable Star Observers of a sample of 5 stars. We find that one star, V CVn, displays a secondary period over 20 times the length of its main period, inconsistent with traditional LSPs. To test if cross-harmonics can result in an LSP or VCVn's extra-long secondary period, we then construct evolutionary tracks and pulsation models of LPVs using Modules for Evolution in Stellar Astrophysics (MESA) and GYRE. After examining the interactions of the fundamental pulsation mode and the first 4 overtones with each other, we do not find evidence that LSPs or V CVn's extra-long secondary period could be caused by cross-harmonics.
Long-secondary-period (LSP) variables are a subclass of long-period variables whose origin is a matter of debate. The current leading hypotheses involve binarity or non-radial pulsations.
We aim to investigate the spectroscopic signatures associated with the LSP variability by targeting two J-type carbon stars exhibiti...
L. Planquart, A. Jorissen, H. Van Winckel· Astronomy & Astrophysics· 0 citations
Long secondary periods (LSPs), observed in about one-third of pulsating red giants, remain unexplained despite decades of study, with binarity and non-radial oscillations as the leading competing hypotheses. If LSP variables are indeed interacting, eccentric binary systems consisting of a red giant and a substellar obj...
P. Kołaczek-Szymański, P. Iwanek, J. Fuller et al.· 0 citations
Abstract Long-period transients are a class of periodic pulsed radio source repeating on the minute to hour timescale. Recently, an increasing number of them are being identified as binary systems, specifically white dwarfs with low-mass main-sequence companions. In this work, we analyse the most luminous long-period t...
Csanád Horváth, N. Hurley-Walker, Zi-Teng Wang et al.· Publications Astronomical So...· 0 citations
Wide-field time-domain radio surveys have recently unveiled a new class of Galactic radio emitter: long period radio transients (LPTs). Despite the rapid pace of discovery, their origins remain poorly understood, with two main theories emerging: slowly spinning magnetars or binary white dwarfs (WDs) with magnetic inter...
G. Mo, A. Anumarlapudi, I. de Ruiter et al.· 0 citations
Blue large-amplitude pulsators (BLAPs) are rare, hot, short-period pulsating stars whose rapid oscillations provide a unique probe of stellar interiors and atmospheres. In this paper, we study two short-period BLAPs in the Galactic bulge, OGLE-BLAP-142 ($P \approx 6.6$ min) and OGLE-BLAP-148 ($P \approx 7.5$ min), by c...
Hao-Ren Ma, Shu-De Mao, Seung-Lee Kim et al.· 0 citations
: Using the 43.18 cm wide-field telescope at Xinjiang Astronomical Observatory, we carried out BVR three-band photometric observations of the variable star BN Tri. The data were reduced and the light curves were analyzed with the software MaxIm DL 6. The light curves in the g, r, and i bands were subjected to three-fre...
Harry Ding· Modern Physical Chemistry Re...· 0 citations
Is your company’s AI sovereign? A practical guide for CIOs on AI vendor lock-in, EU Data Act switching, cloud sovereignty, and testing your exit plan before you need it. The post Sovereignty Is the Option to Leave appeared first on GPT-Lab.
Microsoft Research Blog· microsoft.comOct 30, 2026
Evaluating Microsoft Copilot at enterprise scale requires test data that captures the full complexity of real organizations, yet real enterprise data contains sensitive information that cannot be used for evaluation under any circumstances. The post From synthetic enterprise data evaluations to real Microsoft Copilot AI confidence appeared first on Microsoft Research.
Microsoft Research Blog· microsoft.comOct 29, 2026
Host Sowbhagya Suresh shares some of the latest news and cutting-edge research from across Microsoft—from understanding the challenges facing coding agents to uncovering how people use AI at work and improving extended-range weather forecasting. The post Microsoft Research Focus – Edition #97 appeared first on Microsoft Research.
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