A SEARCH FOR MASS LOSS ON THE CEPHEID INSTABILITY STRIP USING H i 21 cm LINE OBSERVATIONS

Journal Article · Thu Dec 01 04:00:00 EST 2016 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/0004-6256/152/6/200· OSTI ID:22862831

Matthews, L. D. ^[1]; Marengo, M. ^[2]

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1. MIT Haystack Observatory, Off Route 40, Westford, MA 01886 (United States)
2. Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)

We present the results of a search for H i 21 cm line emission from the circumstellar environments of four Galactic Cepheids (RS Pup, X Cyg, ζ Gem, and T Mon) based on observations with the Karl G. Jansky Very Large Array. The observations were aimed at detecting gas associated with previous or ongoing mass loss. Near the long-period Cepheid T Mon, we report the detection of a partial shell-like structure whose properties appear consistent with originating from an earlier epoch of Cepheid mass loss. At the distance of T Mon, the nebula would have a mass (H i+He) of ∼0.5M{sub ⊙}, or ∼6% of the stellar mass. Assuming that one-third of the nebular mass comprises swept-up interstellar gas, we estimate an implied mass-loss rate of M-dot ∼(0.6--2)×10{sup −5} M{sub ⊙} yr{sup −1}. No clear signatures of circumstellar emission were found toward ζ Gem, RS Pup, or X Cyg, although in each case, line-of-sight confusion compromised portions of the spectral band. For the undetected stars, we derive model-dependent 3σ upper limits on the mass-loss rates, averaged over their lifetimes on the instability strip, of ≲(0.3--6)×10{sup −6} M{sub ⊙} yr{sup −1} and estimate the total amount of mass lost to be less than a few percent of the stellar mass.

• OSTI ID: 22862831
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 6 Vol. 152; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CEPHEIDS
DETECTION
DISTANCE
EMISSION
MASS TRANSFER
NEBULAE
STELLAR WINDS