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Article: Limits to mass outflows from late-type dwarf stars

TitleLimits to mass outflows from late-type dwarf stars
Authors
KeywordsRadio Continuum: Stars
Stars: Activity
Stars: Coronae
Stars: Late-Type
Stars: Magnetic Fields
Stars: Mass Loss
Issue Date1996
PublisherInstitute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205
Citation
Astrophysical Journal Letters, 1996, v. 462 n. 2 PART II, p. L91-L94 How to Cite?
AbstractWe show that the mass-loss rates of active late-type dwarf stars must be significantly lower than recent estimates of up to ∼5 × 10∼ -10 M ⊙ yr -1, 4 orders of magnitude higher than that of the Sun. First, we present aperture-synthesis observations at 3.5 mm of the dMe flare stars YZ CMi and AD Leo, during which neither star was detected at an upper limit of 10 mJy. Although compatible with the tentative detection of YZ CMi at 1.1 mm reported by Mullan and coworkers if the millimeter emission originates from a ∼10 4 K, 300 km s -1 wind with Ṁ ≈ 5 × 10 -10 M ⊙ yr -1, we show that such a wind would completely absorb the observed radiation from coronal radio flares originating from close to the stellar surface. From this contradiction, we show that the mass-loss rate of any ∼10 4 K wind with solar-wind-like velocities of 300-600 km s -1 must be less than ∼10 -13 M ⊙ yr -1, more than 3 orders of magnitude below that inferred by Mullan et al. The corresponding upper limit to a wind at a solar-wind-like temperature of ∼10 6 K is Ṁ ≈ 10 -12 M ⊙ yr -1, an order of magnitude below the lower limit predicted theoretically by Badalyan & Livshits. Our arguments apply to all classes of stars that display coronal radio flares, implying that the mass-loss rate of active late-type dwarf stars from any ≈10 4 or ∼10 6 K winds with solar-wind-like velocities can be no more than 1 or 2 orders of magnitude, respectively, higher than the solar mass-loss rate of ∼3 × 10 -14 M ⊙ yr -1. We show that coronal mass ejections also are unlikely to explain the reported millimeter emission from dMe flare stars, and that th,e time-averaged mass-loss rate from such events can be no higher than in the case of a steady, spherically symmetric stellar wind. © 1996. The American Astronomical Society. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/174934
ISSN
2015 Impact Factor: 5.487
2015 SCImago Journal Rankings: 3.369
References

 

DC FieldValueLanguage
dc.contributor.authorLim, Jen_US
dc.contributor.authorWhite, SMen_US
dc.date.accessioned2012-11-26T08:48:13Z-
dc.date.available2012-11-26T08:48:13Z-
dc.date.issued1996en_US
dc.identifier.citationAstrophysical Journal Letters, 1996, v. 462 n. 2 PART II, p. L91-L94en_US
dc.identifier.issn2041-8205en_US
dc.identifier.urihttp://hdl.handle.net/10722/174934-
dc.description.abstractWe show that the mass-loss rates of active late-type dwarf stars must be significantly lower than recent estimates of up to ∼5 × 10∼ -10 M ⊙ yr -1, 4 orders of magnitude higher than that of the Sun. First, we present aperture-synthesis observations at 3.5 mm of the dMe flare stars YZ CMi and AD Leo, during which neither star was detected at an upper limit of 10 mJy. Although compatible with the tentative detection of YZ CMi at 1.1 mm reported by Mullan and coworkers if the millimeter emission originates from a ∼10 4 K, 300 km s -1 wind with Ṁ ≈ 5 × 10 -10 M ⊙ yr -1, we show that such a wind would completely absorb the observed radiation from coronal radio flares originating from close to the stellar surface. From this contradiction, we show that the mass-loss rate of any ∼10 4 K wind with solar-wind-like velocities of 300-600 km s -1 must be less than ∼10 -13 M ⊙ yr -1, more than 3 orders of magnitude below that inferred by Mullan et al. The corresponding upper limit to a wind at a solar-wind-like temperature of ∼10 6 K is Ṁ ≈ 10 -12 M ⊙ yr -1, an order of magnitude below the lower limit predicted theoretically by Badalyan & Livshits. Our arguments apply to all classes of stars that display coronal radio flares, implying that the mass-loss rate of active late-type dwarf stars from any ≈10 4 or ∼10 6 K winds with solar-wind-like velocities can be no more than 1 or 2 orders of magnitude, respectively, higher than the solar mass-loss rate of ∼3 × 10 -14 M ⊙ yr -1. We show that coronal mass ejections also are unlikely to explain the reported millimeter emission from dMe flare stars, and that th,e time-averaged mass-loss rate from such events can be no higher than in the case of a steady, spherically symmetric stellar wind. © 1996. The American Astronomical Society. All rights reserved.en_US
dc.languageengen_US
dc.publisherInstitute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205en_US
dc.relation.ispartofAstrophysical Journal Lettersen_US
dc.subjectRadio Continuum: Starsen_US
dc.subjectStars: Activityen_US
dc.subjectStars: Coronaeen_US
dc.subjectStars: Late-Typeen_US
dc.subjectStars: Magnetic Fieldsen_US
dc.subjectStars: Mass Lossen_US
dc.titleLimits to mass outflows from late-type dwarf starsen_US
dc.typeArticleen_US
dc.identifier.emailLim, J: jjlim@hku.hken_US
dc.identifier.authorityLim, J=rp00745en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.scopuseid_2-s2.0-15444379589en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-15444379589&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume462en_US
dc.identifier.issue2 PART IIen_US
dc.identifier.spageL91en_US
dc.identifier.epageL94en_US
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridLim, J=7403453870en_US
dc.identifier.scopusauthoridWhite, SM=7404079906en_US

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