Limits on detectability of mass loss from cool dwarfs

Mullan, D. J.; Doyle, J. G.; Redman, R. O.; Mathioudakis, M.

doi:10.1086/171781

Cited by 58 publications

(70 citation statements)

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“…This value is within the range of mass-loss rate of MDs in the literature, 10 −15 − 10 −10 M /yr (e.g. Mullan et al 1992;Wood et al 2001;Vidotto et al 2014). It indicates that the wind from the MD could be a reasonable source for electrons.…”

Section: Source Of Electronssupporting

confidence: 80%

A Model of White Dwarf Pulsar Ar Scorpii

Geng

Zhang

Huang

2016

ApJL

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A 3.56-hour white dwarf (WD) -M dwarf (MD) close binary system, AR Scorpii, was recently reported to show pulsating emission in radio, IR, optical, and UV, with a 1.97-minute period, which suggests the existence of a WD with a rotation period of 1.95 minutes. We propose a model to explain the temporal and spectral characteristics of the system. The WD is a nearly perpendicular rotator, with both open field line beams sweeping the MD stellar wind periodically. A bow shock propagating into the stellar wind accelerates electrons in the wind. Synchrotron radiation of these shocked electrons can naturally account for the broad-band (from radio to X-rays) spectral energy distribution of the system.

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Section: Source Of Electronssupporting

confidence: 80%

A Model of White Dwarf Pulsar Ar Scorpii

Geng

Zhang

Huang

2016

ApJL

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“…Flare-related mass-loss rates of (1È2) ] 10~12 M _ yr~1 were also estimated by CW. These estimates of M 0 , although considerably smaller than some earlier claims of from Ñare stars (Mullan et al 1992), are still 100 times M 0 larger than the mass-loss rate from the current Sun. It is not surprising that Ñare-related mass-loss rates from Ñare stars exceed solar rates.…”

contrasting

confidence: 57%

Nonprimordial Deuterium in the Interstellar Medium

Mullan

Linsky

1999

ApJ

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Contrary to a widespread assumption, deuterium is not simply destroyed in stars : deuterium is also synthesized in the atmospheres of active stars. This nonprimordial synthesis of D arises when protons accelerated in Ñares interact with the atmosphere, create a Ñux of free neutrons, and these neutrons then undergo radiative capture on atmospheric protons. Radiative capture does not result in excess production of Li, Be, or B. Ejection of Ñare-processed material contaminates the interstellar medium (ISM), as was originally suggested by Coleman & Worden. Estimates of the amount of Ñare-created D are subject to considerable uncertainties, but we Ðnd, using stellar parameters within permitted ranges, that Ñares may contribute signiÐcantly to the current ISM D content. Observational data indicate that di †er-ent clouds of gas in the ISM exhibit variations in the value of D/H. We suggest that contamination of the ISM by D-enriched material ejected from stellar Ñares contributes to the observed D/H inhomogeneity. More precise estimates of the efficiency of D ejection from Ñares into the solar wind are required to evaluate this suggestion.

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“…Unfortunately, no X-ray or CaII data are available that would allow an estimate ofṀ sw for GJ 842.2. However, GJ 842.2 is not a flare star, and its H α absorption (equivalent width EW H α = −0.545 Å, in Gizis et al 2002) indicates a moderate chromosphere and magnetic activity, and thus only a modest stellar wind (Mullan et al 1992, and Wargelin & Drake 2001. Hence, one can speculate that GJ 842.2 does not have a mass-loss rate larger than 20 times the solar rate and its distant cold grains are unperturbed at age 200 Myr.…”

Section: Debris Disks In Our Sample Of 32 M-dwarfsmentioning

confidence: 99%

Search for cold debris disks around M-dwarfs

Lestrade¹,

Wyatt²,

Bertoldi³

et al. 2006

A&A

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Debris disks are believed to be related to planetesimals left over around stars after planet formation has ceased. The frequency of debris disks around M-dwarfs which account for 70% of the stars in the Galaxy is unknown while constrains have already been found for A-to K-type stars. We have searched for cold debris disks around 32 field M-dwarfs by conducting observations at λ = 850 µm with the SCUBA bolometer array camera at the JCMT and at λ = 1.2 mm with the MAMBO array at the IRAM 30-m telescopes. This is the first survey of a large sample of M-dwarfs conducted to provide statistical constraints on debris disks around this type of stars. We have detected a new debris disk around the M0.5 dwarf GJ 842.2 at λ = 850 µm, providing evidence for cold dust at large distance from this star (∼300 AU). By combining the results of our survey with the ones of Liu et al. (2004), we estimate for the first time the detection rate of cold debris disks around field M-dwarfs with ages between 20 and 200 Myr. This detection rate is 13 +6 −8 % and is consistent with the detection rate of cold debris disks (9-23%) around A-to K-type main sequence stars of the same age. This is an indication that cold disks may be equally prevalent across stellar spectral types.

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Limits on detectability of mass loss from cool dwarfs

Cited by 58 publications

References 0 publications

A Model of White Dwarf Pulsar Ar Scorpii

A Model of White Dwarf Pulsar Ar Scorpii

Nonprimordial Deuterium in the Interstellar Medium

Search for cold debris disks around M-dwarfs

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