FAR-UV SPECTROSCOPY OF THE PLANET-HOSTING STAR WASP-13: HIGH-ENERGY IRRADIANCE, DISTANCE, AGE, PLANETARY MASS-LOSS RATE, AND CIRCUMSTELLAR ENVIRONMENT

The radio emission from supernovae provides a direct probe of a supernova’s circumstellar environment, which presumably was established by mass-loss episodes in the late stages of the progenitor’s presupernova evolution. The observed synchrotron emission is generated by the SN shock interacting with the relatively high-density circumstellar medium which has been fully ionized and heated by the initial UV/X-ray flash. The study of radio supernovae therefore provides many clues to and constraints on stellar evolution. We will present the recent results on several cases, including SN 1980K, whose recent abrupt decline provides us with a stringent constraint on the progenitor’s initial mass; SN 1993J, for which the profile of the wind matter supports the picture of the progenitor’s evolution in an interacting binary system; and SN 1979C, where a clear change in presupernova mass-loss rate occurred about 104 years before explosion. Other examples, such as SNe 19941 and 1996cb, will also be discussed.

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An Exploratory Study on a High-Energy Flux (HEF) Calorimeter to Characterize Flammability of Advanced Engineered Polymers: Phase 1 - Ignition and Mass Loss Rate

10.21236/ada369237 ◽

1999 ◽

Cited By ~ 1

Author(s):

Archibald Tewarson ◽

Wai Chin ◽

Richard Shuford

Keyword(s):

Mass Loss ◽

Energy Flux ◽

Exploratory Study ◽

Loss Rate ◽

Mass Loss Rate ◽

Phase 1 ◽

High Energy

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Constraining red supergiant mass-loss prescriptions through supernova radio properties

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slab018 ◽

2021 ◽

Vol 503 (1) ◽

pp. L28-L32

Author(s):

Takashi J Moriya

Keyword(s):

Mass Loss ◽

Rise Time ◽

Loss Rate ◽

Mass Loss Rate ◽

Strong Dependence ◽

Core Collapse ◽

Type Ii ◽

Red Supergiants ◽

Circumstellar Environment ◽

Peak Luminosity

ABSTRACT Supernova (SN) properties in radio strongly depend on their circumstellar environment and they are an important probe to investigate the mass-loss of SN progenitors. Recently, core-collapse SN observations in radio have been assembled and the rise time and peak luminosity distribution of core-collapse SNe at 8.4 GHz has been estimated. In this paper, we constrain the mass-loss prescriptions for red supergiants (RSGs) by using the rise time and peak luminosity distribution of Type II SNe in radio. We take the de Jager and van Loon mass-loss rates for RSGs, calculate the rise time and peak luminosity distribution based on them, and compare the results with the observed distribution. We found that the de Jager mass-loss rate explains the widely spread radio rise time and peak luminosity distribution of Type II SNe well, while the van Loon mass-loss rate predicts a relatively narrow range for the rise time and peak luminosity. We conclude that the mass-loss prescriptions of RSGs should have strong dependence on the luminosity as in the de Jager mass-loss rate to reproduce the widely spread distribution of the rise time and peak luminosity in radio observed in Type II SNe.

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Wind and nebula of the M 33 variable GR 290 (WR/LBV)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732540 ◽

2018 ◽

Vol 617 ◽

pp. A51 ◽

Cited By ~ 1

Author(s):

Olga Maryeva ◽

Gloria Koenigsberger ◽

Oleg Egorov ◽

Corinne Rossi ◽

Vito Francesco Polcaro ◽

...

Keyword(s):

Interstellar Medium ◽

Mass Loss ◽

Loss Rate ◽

Mass Loss Rate ◽

Model Atmosphere ◽

General Context ◽

Thermodynamical Equilibrium ◽

Bolometric Luminosity ◽

Non Local ◽

Circumstellar Environment

Context. GR 290 (M 33/V532 = Romano’s Star) is a suspected post-luminous blue variable star located in M 33 galaxy that shows a rare Wolf–Rayet (WR) spectrum during its minimum light phase. In spite of many studies, its atmospheric structure, its circumstellar environment, and its place in the general context of massive stars’ evolution is poorly known. Aims. We present a detailed study of this star’s wind and mass loss, and a study of the circumstellar environment associated to the star. Methods. Long-slit spectra of GR 290 were obtained during its present minimum luminosity phase with the Gran Telescopio Canarias covering the ∼3600–7500 Å wavelength range together with contemporaneous photometry using B, V, R and I filters. The data were compared with non-local thermodynamical equilibrium (non-LTE) model atmosphere synthetic spectra computed with CMFGEN code and with models for ionized interstellar medium regions computed with CLOUDY code. Results. The current mV = 18.8 mag is the faintest at which this source has ever been observed. The non-LTE models indicate effective temperatures of Teff = 27 000–30 000 K at radius R2/3 = 27−21 R⊙ and mass-loss rate Ṁ = 1.5 × 10−5 M⊙yr−1. The terminal wind speed v∞ = 620 km s−1 is faster than ever before recorded, while the current luminosity L* = (3.1–3.7) × 105L⊙ is the lowest ever deduced. The star is overabundant in He and N and underabundant in C and O. It is surrounded by an unresolved compact H II region with dimensions ≤4 pc, from where H-Balmer, He I lines, and [O III] and [N II] are detected. In addition, we find emission from a more extended interstellar medium (ISM) region, which appears to be asymmetric, with a larger extent to the east (16–40 pc) than to the west. Conclusions. In the present long lasting visual minimum, GR 290 is in a lower bolometric luminosity state with higher mass-loss rate. The nearby nebular emission seems to suggest that the star has undergone significant mass loss over the past 104–105 yr and is nearing the end stages of its evolution.

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Three-dimensional hydrodynamic simulations of the upper atmosphere of π Men c: Comparison with Lyα transit observations

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038363 ◽

2020 ◽

Vol 639 ◽

pp. A109

Author(s):

I. F. Shaikhislamov ◽

L. Fossati ◽

M. L. Khodachenko ◽

H. Lammer ◽

A. García Muñoz ◽

...

Keyword(s):

Mass Loss ◽

Stellar Wind ◽

Loss Rate ◽

Mass Loss Rate ◽

Three Dimensional ◽

High Energy ◽

Planetary Atmosphere ◽

Upper Atmosphere ◽

Energy Emission ◽

High Energy Emission

Context. π Men c is the first planet to have been discovered by the Transiting Exoplanet Survey Satellite. It orbits a bright, nearby star and has a relatively low average density, making it an excellent target for atmospheric characterisation. The existing planetary upper atmosphere models of π Men c predict significant atmospheric escape, but Lyα transit observations indicate the non-detection of hydrogen escaping from the planet. Aims. Our study is aimed at constraining the conditions of the wind and high-energy emission of the host star and reproducing the non-detection of Lyα planetary absorption. Methods. We modelled the escaping planetary atmosphere, the stellar wind, and their interaction employing a multi-fluid, three-dimensional hydrodynamic code. We assumed a planetary atmosphere composed of hydrogen and helium. We ran models varying the stellar high-energy emission and stellar mass-loss rate, and, for each case, we further computed the Lyα synthetic planetary atmospheric absorption and compared it with the observations. Results. We find that a non-detection of Lyα in absorption employing the stellar high-energy emission estimated from far-ultraviolet and X-ray data requires a stellar wind with a stellar mass-loss rate about six times lower than solar. This result is a consequence of the fact that, for π Men c, detectable Lyα absorption can be caused exclusively by energetic neutral atoms, which become more abundant with increasing velocity or density of the stellar wind. By considering, instead, that the star has a solar-like wind, the non-detection requires a stellar ionising radiation about four times higher than estimated. The reason for this is that despite the fact that a stronger stellar high-energy emission ionises hydrogen more rapidly, it also increases the upper atmosphere heating and expansion, pushing the interaction region with the stellar wind farther away from the planet, where the planet atmospheric density that remains neutral becomes smaller and the production of energetic neutral atoms less efficient. Conclusions. Comparing the results of our grid of models with what is expected and estimated for the stellar wind and high-energy emission, respectively, we support the idea that it is likely that the atmosphere of π Men c is not hydrogen-dominated. Therefore, future observations should focus on the search for planetary atmospheric absorption at the position of lines of heavier elements, such as He, C, and O.

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CO envelope of the symbiotic star R Aquarii seen by ALMA

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833394 ◽

2018 ◽

Vol 616 ◽

pp. A61 ◽

Cited By ~ 8

Author(s):

S. Ramstedt ◽

S. Mohamed ◽

T. Olander ◽

W. H. T. Vlemmings ◽

T. Khouri ◽

...

Keyword(s):

Mass Loss ◽

Spatial Resolution ◽

White Dwarf ◽

Loss Rate ◽

Mass Loss Rate ◽

Line Emission ◽

High Energy ◽

Small Sample ◽

Symbiotic Star ◽

Binary Separation

The symbiotic star R Aqr is part of a small sample of binary AGB stars observed with the Atacama Large Millimeter/submillimeter Array (ALMA). The sample stars are: R Aqr, Mira, W Aql, and π1 Gru. The sample covers a range in binary separation and wind properties, where R Aqr is the source with the smallest separation. The R Aqr binary pair consists of an M-type AGB star and a white dwarf at a separation of 45 mas, equivalent to about 10 AU at 218 pc. The aim of the ALMA study is to investigate the dependence of the wind shaping on the binary separation and to provide constraints for hydrodynamical binary interaction models. R Aqr is particularly interesting as the source with the smallest separation and a complex circumstellar environment that is strongly affected by the interaction between the two stars and by the high-energy radiation resulting from this interaction and from the hot white dwarf companion. The CO(J = 3 →2) line emission has been observed with ALMA at ~0.5′′ spatial resolution. The CO envelope around the binary pair is marginally resolved, showing what appears to be a rather complex distribution. The outer radius of the CO emitting region is estimated from the data and found to be about a factor of 10 larger than previously thought. This implies an average mass-loss rate during the past ~100 yr of Ṁ ≈ 2×10−7 M⊙ yr−1, a factor of 45 less than previous estimates. The channel maps are presented and the molecular gas distribution is discussed and set into the context of what was previously known about the system from multiwavelength observations. Additional molecular line emission detected within the bandwidth covered by the ALMA observations is also presented. Because of the limited extent of the emission, firm conclusions about the dynamical evolution of the system will have to wait for higher spatial resolution observations. However, the data presented here support the assumption that the mass-loss rate from the Mira star strongly varies and is focused on the orbital plane.

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