Abstract

Common envelopes (CEs) are thought to be the main method for producing tight binary systems in the universe, as the orbital period shrinks by several orders of magnitude during this phase. Despite their importance for many stellar evolution channels, direct detections are rare, and thus observational constraints on common envelope physics are often inferred from post-CE populations. Recently, galactic population observations suggest that the CE phase must be highly inefficient at using orbital energy to drive envelope ejection for low-mass systems and highly efficient for high-mass systems. Such a dichotomy has been explained by an interplay between convection, radiation, and orbital decay. If convective transport to the surface occurs faster than the orbit decays, the CE self-regulates and radiatively cools. Once the orbit shrinks such that convective transport is slow compared to orbital decay, a burst occurs as the release of orbital energy can be far in excess of that required to unbind the envelope. With the anticipation of first light for the Rubin Observatory, we calculate observable quantities for convective common envelopes. In particular, for low-mass systems, we produce observables, including light curves and apparent magnitudes for the Rubin filters. For high-mass systems, we identify binaries where convective effects are important and calculate corresponding light curves. We explore convective CE envelope models for two candidate systems, M101 OT2015-1 and OGLE-2002-BLG-360, where convection provides a reasonable explanation for the observational data. In general, convection imparts a distinct, long-term signature in the light curves, which should be detectable with upcoming transient surveys.

Library of Congress Subject Headings

Double stars--Observations; Convection (Astrophysics)--Mathematical models; Stars--Evolution

Publication Date

6-2025

Document Type

Dissertation

Student Type

Graduate

Degree Name

Astrophysical Sciences and Technology (Ph.D.)

Department, Program, or Center

Physics and Astronomy, School of

College

College of Science

Advisor

Jason Nordhaus

Advisor/Committee Member

Michael Richmond

Advisor/Committee Member

Orsola De Marco

Campus

RIT – Main Campus

Plan Codes

ASTP-PHD

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