Periodic 6.7 GHz $\mathrm{CH_3OH}$ maser emission in G353.273+0.641: First candidate for a pulsating high-mass protostar

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Auteurs principaux: Harajiri, Sohta, Motogi, Kazuhito, Nakamura, Ryota, Yonekura, Yoshinori, Tanabe, Yoshihiro, Fujisawa, Kenta
Format: Preprint
Publié: 2026
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author Harajiri, Sohta
Motogi, Kazuhito
Nakamura, Ryota
Yonekura, Yoshinori
Tanabe, Yoshihiro
Fujisawa, Kenta
author_facet Harajiri, Sohta
Motogi, Kazuhito
Nakamura, Ryota
Yonekura, Yoshinori
Tanabe, Yoshihiro
Fujisawa, Kenta
contents We report on the periodic flux variations in the 6.7 GHz $\mathrm{CH_3OH}$ maser associated with the high-mass protostar G353.273+0.641, based on 13 yr of monitoring mainly by the Hitachi 32 m telescope. We identified a periodicity of 309 days based on a nearly complete light curve, with 833 epochs every few days. A strong correlation is found between the maser and the mid-infrared fluxes at 3.4 and 4.6 $μ$m observed by NEOWISE during these periods, suggesting that the maser emission responds to variations in the protostellar luminosity. The average profile of the maser light curve is asymmetric and shows a steep drop in intensity just before the brightening, resembling that of some pulsating variable stars. Assuming a protostellar pulsation as the origin of maser periodicity, the observed period implies a cool and highly bloated, red supergiant-like structure. Such a bloated structure is consistent with a theoretical model of protostellar evolution under high accretion rates. The inferred protostellar parameters are broadly consistent with the theoretical model of pulsational instability during the early phase of high-mass star formation. However, a periodic accretion scenario caused by an unresolved compact protobinary cannot be completely ruled out. Several irregular peaks that deviate from the periodicity may result from episodic accretion phenomena or jet-launching events independent of the protostellar pulsation. Extremely high-resolution imaging with next-generation interferometers such as the ngVLA will provide a conclusive test for both the protostellar pulsation and the binary accretion scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2602_03148
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Periodic 6.7 GHz $\mathrm{CH_3OH}$ maser emission in G353.273+0.641: First candidate for a pulsating high-mass protostar
Harajiri, Sohta
Motogi, Kazuhito
Nakamura, Ryota
Yonekura, Yoshinori
Tanabe, Yoshihiro
Fujisawa, Kenta
Solar and Stellar Astrophysics
Astrophysics of Galaxies
We report on the periodic flux variations in the 6.7 GHz $\mathrm{CH_3OH}$ maser associated with the high-mass protostar G353.273+0.641, based on 13 yr of monitoring mainly by the Hitachi 32 m telescope. We identified a periodicity of 309 days based on a nearly complete light curve, with 833 epochs every few days. A strong correlation is found between the maser and the mid-infrared fluxes at 3.4 and 4.6 $μ$m observed by NEOWISE during these periods, suggesting that the maser emission responds to variations in the protostellar luminosity. The average profile of the maser light curve is asymmetric and shows a steep drop in intensity just before the brightening, resembling that of some pulsating variable stars. Assuming a protostellar pulsation as the origin of maser periodicity, the observed period implies a cool and highly bloated, red supergiant-like structure. Such a bloated structure is consistent with a theoretical model of protostellar evolution under high accretion rates. The inferred protostellar parameters are broadly consistent with the theoretical model of pulsational instability during the early phase of high-mass star formation. However, a periodic accretion scenario caused by an unresolved compact protobinary cannot be completely ruled out. Several irregular peaks that deviate from the periodicity may result from episodic accretion phenomena or jet-launching events independent of the protostellar pulsation. Extremely high-resolution imaging with next-generation interferometers such as the ngVLA will provide a conclusive test for both the protostellar pulsation and the binary accretion scenarios.
title Periodic 6.7 GHz $\mathrm{CH_3OH}$ maser emission in G353.273+0.641: First candidate for a pulsating high-mass protostar
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2602.03148