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The Luminous Blue Variable RMC 127 as Seen with ALMA and ATCA

Agliozzo, C. and Trigilio, C. and Pignata, G. and Phillips, N. M. and Nikutta, R. and Leto, P. and Umana, G. and Ingallinera, A. and Buemi, C. and Bauer, F. E. and Paladini, R. and Noriega-Crespo, A. and Prieto, J. L. and Massardi, M. and Cerrigone, L. (2017) The Luminous Blue Variable RMC 127 as Seen with ALMA and ATCA. Astrophysical Journal, 841 (2). Art. No. 130. ISSN 1538-4357.

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We present ALMA and ATCA observations of the luminous blue variable RMC 127. The radio maps show for the first time the core of the nebula and evidence that the nebula is strongly asymmetric with a Z-pattern shape. Hints of this morphology are also visible in the archival Hubble Space Telescope Hα image, which overall resembles the radio emission. The emission mechanism in the outer nebula is optically thin free–free in the radio. At high frequencies, a component of point-source emission appears at the position of the star, up to the ALMA frequencies. The rising flux density distribution (S_ν ~ ν^(0.78±0.05)) of this object suggests thermal emission from the ionized stellar wind and indicates a departure from spherical symmetry with n_e(r) ∝ r^(-2). We examine different scenarios to explain this excess of thermal emission from the wind and show that this can arise from a bipolar outflow, supporting the suggestion by other authors that the stellar wind of RMC 127 is aspherical. We fit the data with two collimated ionized wind models, and we find that the mass-loss rate can be a factor of two or more smaller than in the spherical case. We also fit the photometry obtained by IR space telescopes and deduce that the mid- to far-IR emission must arise from extended, cool (~80 K) dust within the outer ionized nebula. Finally, we discuss two possible scenarios for the nebular morphology: the canonical single-star expanding shell geometry and a precessing jet model assuming the presence of a companion star.

Item Type:Article
Related URLs:
URLURL TypeDescription
Agliozzo, C.0000-0003-1749-2542
Trigilio, C.0000-0002-1216-7831
Pignata, G.0000-0003-0006-0188
Ingallinera, A.0000-0002-3137-473X
Bauer, F. E.0000-0002-8686-8737
Paladini, R.0000-0002-5158-243X
Noriega-Crespo, A.0000-0002-6296-8960
Prieto, J. L.0000-0003-0943-0026
Cerrigone, L.0000-0002-5537-7134
Additional Information:© 2017 The American Astronomical Society. Received 2016 May 25; revised 2017 May 9; accepted 2017 May 9; published 2017 June 5. We are thankful to Yazam Momany for assistance with the VISIR data. We thank the referee for thorough feedback, which has helped to improve and clarify our presentation of this work. We acknowledge support from FONDECYT grant No. 3150463 (C.A.), FONDECYT grant No. 3140436 (R.N.), FONDECYT Regular 1141218 (F.E.B.), FONDECYT grant 1151445 (J.L.P.), CONICYT-Chile grants Basal-CATA PFB-06/2007 (F.E.B.), "EMBIGGEN" Anillo ACT1101 (F.E.B.), and the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS (C.A., G.P., J.L.P., F.E.B.). We also wish to thank the staff at ESO, ALMA, and ATCA who made these observations possible. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2013.1.00450.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This paper also includes data collected at the European Organisation for Astronomical Research in the southern Hemisphere under ESO programmes 095.D-0433(A) and 095.D-0433(B). The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. This work made use of PyAstronomy. Facilities: ATCA, ALMA, VLT.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)3150463
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)3140436
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1141218
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1151445
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)Anillo ACT1101
Iniciativa Científica Milenio del Ministerio de Economía, Fomento y TurismoIC120009
Subject Keywords:stars: individual (RMC 127) ; stars: massive; stars: mass-loss; stars: rotation; stars: winds, outflows; submillimeter: stars
Issue or Number:2
Record Number:CaltechAUTHORS:20170606-132315552
Persistent URL:
Official Citation:C. Agliozzo et al 2017 ApJ 841 130
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77971
Deposited By: Tony Diaz
Deposited On:06 Jun 2017 21:11
Last Modified:09 Mar 2020 13:19

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