uu.seUppsala universitets publikasjoner
Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
A detailed view of the gas shell around R Sculptoris with ALMA
Chalmers, Onsala Space Observ, Dept Earth & Space Sci, S-43992 Onsala, Sweden..
Chalmers, Onsala Space Observ, Dept Earth & Space Sci, S-43992 Onsala, Sweden..
Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria..
Chalmers, Onsala Space Observ, Dept Earth & Space Sci, S-43992 Onsala, Sweden..
Vise andre og tillknytning
2016 (engelsk)Inngår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 586, artikkel-id A5Artikkel i tidsskrift (Fagfellevurdert) Published
Resurstyp
Text
Abstract [en]

Context. During the asymptotic giant branch (AGB) phase, stars undergo thermal pulses - short-lived phases of explosive helium burning in a shell around the stellar core. Thermal pulses lead to the formation and mixing-up of new elements to the stellar surface. They are hence fundamental to the chemical evolution of the star and its circumstellar envelope. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star, several of which have been observed around carbon-rich AGB stars. Aims. We aim to determine the physical properties of the detached gas shell around R Sculptoris, in particular the shell mass and temperature, and to constrain the evolution of the mass-loss rate during and after a thermal pulse. Methods. We analyse (CO)-C-12(1-0), (CO)-C-12(2-1), and (CO)-C-12(3-2) emission, observed with the Atacama Large Millimeter/submillimeter Array (ALMA) during Cycle 0 and complemented by single-dish observations. The spatial resolution of the ALMA data allows us to separate the detached shell emission from the extended emission inside the shell. We perform radiative transfer modelling of both components to determine the shell properties and the post-pulse mass-loss properties. Results. The ALMA data show a gas shell with a radius of 19.'' 5 expanding at 14.3 km s(-1). The different scales probed by the ALMA Cycle 0 array show that the shell must be entirely filled with gas, contrary to the idea of a detached shell. The comparison to single-dish spectra and radiative transfer modelling confirms this. We derive a shell mass of 4.5 x 10(-3) M-circle dot with a temperature of 50 K. Typical timescales for thermal pulses imply a pulse mass-loss rate of 2.3 x 10(-5) M-circle dot yr(-1). For the post-pulse mass-loss rate, we find evidence for a gradual decline of the mass-loss rate, with an average value of 1.6 x 10(-5) M-circle dot yr(-1). The total amount of mass lost since the last thermal pulse is 0.03 M-circle dot, a factor four higher compared to classical models, with a sharp decline in mass-loss rate immediately after the pulse. Conclusions. We find that the mass-loss rate after a thermal pulse has to decline more slowly than generally expected from models of thermal pulses. This may cause the star to lose significantly more mass during a thermal pulse cycle, which affects the lifetime on the AGB and the chemical evolution of the star, its circumstellar envelope, and the interstellar medium.

sted, utgiver, år, opplag, sider
2016. Vol. 586, artikkel-id A5
Emneord [en]
stars: AGB and post-AGB, binaries: general, stars: carbon, stars: evolution, stars: mass-loss
HSV kategori
Identifikatorer
URN: urn:nbn:se:uu:diva-281832DOI: 10.1051/0004-6361/201527128ISI: 000369715900016OAI: oai:DiVA.org:uu-281832DiVA, id: diva2:917263
Forskningsfinansiär
EU, FP7, Seventh Framework Programme, 623898.11EU, European Research Council, 614264Swedish Research CouncilTilgjengelig fra: 2016-04-06 Laget: 2016-03-30 Sist oppdatert: 2017-11-30bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekst

Personposter BETA

Ramstedt, Sofia

Søk i DiVA

Av forfatter/redaktør
Ramstedt, Sofia
Av organisasjonen
I samme tidsskrift
Astronomy and Astrophysics

Søk utenfor DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 332 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf