ALMA sub-mm maser and dust distribution of VY Canis Majoris

Richards, A. M. S.; Impellizzeri, C. M. V.; Humphreys, E. M. L.; Vlahakis, C.; Vlemmings, Wouter; Baudry, A.; Beck, E. De; Decin, L.; Etoka, S.; Gray, M. D.; Harper, G. M.; Hunter, T. R.; Kervella, P.; Kerschbaum, F.; McDonald, Iain; Melnick, Gary J.; Müller, S.; Neufeld, David A.; O’Gorman, Eamon; Parfenov, S. Yu.; Peck, A. B.; Shinnaga, Hiroko; Соболев, А. М.; Testi, L.; Uscanga, L.; Wootten, Alwyn; Yates, J. A.; Zijlstra, A. A.

doi:10.1051/0004-6361/201425024

Cited by 37 publications

(21 citation statements)

References 43 publications

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“…Strong asymmetries also exist in some evolved stars, either as clumps or discs (e.g. Richards et al 2014;Leão et al 2015;Lykou et al 2015;Kervella et al 2016). …”

Section: E2 Reddening Of the Central Star And The Role Of Geometrymentioning

confidence: 99%

Fundamental parameters and infrared excesses of Tycho–Gaia stars

McDonald

Zijlstra

Watson

2017

Monthly Notices of the Royal Astronomical Society

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114

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Effective temperatures and luminosities are calculated for 1 475 921 Tycho-2 and 107 145 Hipparcos stars, based on distances from Gaia Data Release 1. Parameters are derived by comparing multi-wavelength archival photometry to bt-settl model atmospheres. The 1σ uncertainties for the Tycho-2 and Hipparcos stars are ±137 K and ±125 K in temperature and ±35 per cent and ±19 per cent in luminosity. The luminosity uncertainty is dominated by that of the Gaia parallax. Evidence for infrared excess between 4.6 and 25 µm is found for 4256 stars, of which 1883 are strong candidates. These include asymptotic giant branch (AGB) stars, Cepheids, Herbig Ae/Be stars, young stellar objects, and other sources. We briefly demonstrate the capabilities of this dataset by exploring local interstellar extinction, the onset of dust production in AGB stars, the age and metallicity gradients of the solar neighbourhood and structure within the Gould Belt. We close by discussing the potential impact of future Gaia data releases.

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“…Strong asymmetries also exist in some evolved stars, either as clumps or discs (e.g. Richards et al 2014;Leão et al 2015;Lykou et al 2015;Kervella et al 2016). …”

Section: E2 Reddening Of the Central Star And The Role Of Geometrymentioning

confidence: 99%

Fundamental parameters and infrared excesses of Tycho–Gaia stars

McDonald

Zijlstra

Watson

2017

Monthly Notices of the Royal Astronomical Society

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114

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“…They presented new detections from six Mira variables including IK Tau. Richards et al (2014) presented Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 658-GHz water maser towards VY CMa. The interferometric observations with high angular resolution enabled us to locate water masers with milliarcsecond precision.…”

Section: Introductionmentioning

confidence: 99%

Model of the vibrationally excited H2O maser at 658 GHz in circumstellar envelopes around asymptotic giant branch stars

Nesterenok

2015

Monthly Notices of the Royal Astronomical Society

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The model is presented of H 2 O maser in the 1 10 − 1 01 line within the first excited vibrational state of the molecule around oxygen-rich asymptotic giant branch stars. It is suggested that the maser cloud is located in the inner layers of the circumstellar envelope where intense dust formation takes place. The calculations took into account rotational levels belonging to the five lowest vibrational states of the H 2 O molecule. The model predicts the gain values of the 658-GHz maser about 10 −14 − 10 −13 cm −1 at H 2 molecule concentrations 10 9 − 10 11 cm −3 and at high ortho-H 2 O concentrations 10 5 cm −3 . The gas temperatures 1000 -1500 K are considered to be a necessary condition for the effective maser operation. Results are presented for other maser transitions of the excited vibrational states of the molecule.

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“…The OH molecules are formed when H2O molecules at the periphery of the inner envelope are photo-dissociated by interstellar ultra-violet radiation. In addition to OH masers, SiO and H2O masers are used to probe the velocities of the inner dust-free zones, and accelerating wind zones, respectively (Richards et al 2014). All three types of masers are critical to understanding the kinematics of dust-driven winds.…”

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confidence: 99%

The wind speeds, dust content, and mass-loss rates of evolved AGB and RSG stars at varying metallicity

Goldman

Loon

Zijlstra

et al. 2016

Mon. Not. R. Astron. Soc.

146

118

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We present the results of our survey of 1612 MHz circumstellar OH maser emission from asymptotic giant branch (AGB) stars and red supergiants (RSGs) in the Large Magellanic Cloud. We have discovered four new circumstellar maser sources in the LMC, and increased the number of reliable wind speeds from IR stars in the LMC from 5 to 13. Using our new wind speeds, as well as those from Galactic sources, we have derived an updated relation for dust driven winds: v exp ∝ ZL 0.4 . We compare the sub-solar metallicity LMC OH/IR stars with carefully selected samples of more metal-rich OH/IR stars, also at known distances, in the Galactic Centre and Galactic Bulge. For 8 of the Bulge stars we derive pulsation periods for the first time, using near-IR photometry from the VVV survey. We have modeled our LMC OH/IR stars and developed an empirical method of deriving gas-to-dust ratios and mass loss rates by scaling the models to the results from maser profiles. We have done this also for samples in the Galactic Centre and Bulge and derived a new mass loss prescription that includes luminosity, pulsation period, and gas-to-dust ra-tioṀ = 1.06 +3.5 −0.8 ·10 −5 (L/10 4 L ) 0.9±0.1 (P/500 d) 0.75±0.3 (r gd /200) −0.03±0.07 M yr −1 . The tightest correlation is found between mass loss rate and luminosity. We find that the gas-to-dust ratio has little effect on the mass loss of oxygen-rich AGB stars and RSGs within the Galaxy and the LMC. This suggests that mass loss of oxygen-rich AGB stars and RSGs is (nearly) independent of metallicity between a half and twice solar.

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ALMA sub-mm maser and dust distribution of VY Canis Majoris

Cited by 37 publications

References 43 publications

Fundamental parameters and infrared excesses of Tycho–Gaia stars

Fundamental parameters and infrared excesses of Tycho–Gaia stars

Model of the vibrationally excited H2O maser at 658 GHz in circumstellar envelopes around asymptotic giant branch stars

The wind speeds, dust content, and mass-loss rates of evolved AGB and RSG stars at varying metallicity

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