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Article: Limits to mass outflows from late-type dwarf stars
Title | Limits to mass outflows from late-type dwarf stars |
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Authors | |
Keywords | Radio Continuum: Stars Stars: Activity Stars: Coronae Stars: Late-Type Stars: Magnetic Fields Stars: Mass Loss |
Issue Date | 1996 |
Publisher | Institute 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? |
Abstract | We 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 Identifier | http://hdl.handle.net/10722/174934 |
ISSN | 2023 Impact Factor: 8.8 2023 SCImago Journal Rankings: 2.766 |
References |
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Lim, J | en_US |
dc.contributor.author | White, SM | en_US |
dc.date.accessioned | 2012-11-26T08:48:13Z | - |
dc.date.available | 2012-11-26T08:48:13Z | - |
dc.date.issued | 1996 | en_US |
dc.identifier.citation | Astrophysical Journal Letters, 1996, v. 462 n. 2 PART II, p. L91-L94 | en_US |
dc.identifier.issn | 2041-8205 | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/174934 | - |
dc.description.abstract | We 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.language | eng | en_US |
dc.publisher | Institute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205 | en_US |
dc.relation.ispartof | Astrophysical Journal Letters | en_US |
dc.subject | Radio Continuum: Stars | en_US |
dc.subject | Stars: Activity | en_US |
dc.subject | Stars: Coronae | en_US |
dc.subject | Stars: Late-Type | en_US |
dc.subject | Stars: Magnetic Fields | en_US |
dc.subject | Stars: Mass Loss | en_US |
dc.title | Limits to mass outflows from late-type dwarf stars | en_US |
dc.type | Article | en_US |
dc.identifier.email | Lim, J: jjlim@hku.hk | en_US |
dc.identifier.authority | Lim, J=rp00745 | en_US |
dc.description.nature | link_to_subscribed_fulltext | en_US |
dc.identifier.scopus | eid_2-s2.0-15444379589 | en_US |
dc.relation.references | http://www.scopus.com/mlt/select.url?eid=2-s2.0-15444379589&selection=ref&src=s&origin=recordpage | en_US |
dc.identifier.volume | 462 | en_US |
dc.identifier.issue | 2 PART II | en_US |
dc.identifier.spage | L91 | en_US |
dc.identifier.epage | L94 | en_US |
dc.publisher.place | United Kingdom | en_US |
dc.identifier.scopusauthorid | Lim, J=7403453870 | en_US |
dc.identifier.scopusauthorid | White, SM=7404079906 | en_US |
dc.identifier.issnl | 2041-8205 | - |