Radial velocity variations in the young eruptive star EX Lupi*'**

Astronomy and Astrophysics 561 (2014): A61 reproduced with permission from Astronomy & Astrophysics

Detalles Bibliográficos
Autores: Mohler-Fischer, Maren, Sicilia-Aguilar, Aurora, Ábrahám, P., Curé, Michel, Launhardt, Ralf, Moór, Attila, Müller, André Frotta, Kóspál, Á., Henning, Th., Kiss, Cs.
Tipo de recurso: artículo
Fecha de publicación:2014
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/665162
Acceso en línea:http://hdl.handle.net/10486/665162
https://dx.doi.org/10.1051/0004-6361/201322428
Access Level:acceso abierto
Palabra clave:Circumstellar matter
Infrared: stars
Stars: formation
Stars: individual: EX Lupi
Techniques: radial velocities
Física
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spelling Radial velocity variations in the young eruptive star EX Lupi*'**Mohler-Fischer, MarenSicilia-Aguilar, AuroraÁbrahám, P.Curé, MichelLaunhardt, RalfMoór, AttilaMüller, André FrottaKóspál, Á.Henning, Th.Kiss, Cs.Circumstellar matterInfrared: starsStars: formationStars: individual: EX LupiTechniques: radial velocitiesFísicaAstronomy and Astrophysics 561 (2014): A61 reproduced with permission from Astronomy & AstrophysicsContext. EX Lup-type objects (EXors) are low-mass pre-main sequence objects characterized by optical and near-infrared outbursts attributed to highly enhanced accretion from the circumstellar disk onto the star. Aims. The trigger mechanism of EXor outbursts is still debated. One type of theory requires a close (sub)stellar companion that perturbs the inner part of the disk and triggers the onset of the enhanced accretion. Here, we study the radial velocity (RV) variations of EX Lup, the prototype of the EXor class, and test whether they can be related to a close companion. Methods. We conducted a five-year RV survey, collecting 54 observations with HARPS and FEROS. We analyzed the activity of EX Lup by checking the bisector, the equivalent width of the Ca 8662 Å line, the asymmetry of the Ca II K line, the activity indicator S FEROS, the asymmetry of the cross-correlation function, the line depth ratio of the VI/FeI lines, and the TiO, CaH 2, CaH 3, CaOH, and Hα indices. We complemented the RV measurements with a 14-day optical/infrared photometric monitoring to look for signatures of activity or varying accretion. Results. We found that the RV of EX Lup is periodic (P = 7.417 d), with stable period, semi-amplitude (2.2 km s-1), and phase over at least four years of observations. This period is not present in any of the above-mentioned activity indicators. However, the RVs of narrow metallic emission lines suggest the same period, but with an anti-correlating phase. The observed absorption line RVs can be fitted with a Keplerian solution around a 0.6 M central star with msini = (14.7 ± 0.7) MJup and eccentricity of e = 0.24. Alternatively, we attempted to model the observations with a cold or hot stellar spot as well. We found that in our simple model, the spot parameters needed to reproduce the RV semi-amplitude are in contradiction with the photometric variability, making the spot scenario unlikely. Conclusions. We qualitatively discuss two possibilities to explain the RV data: a geometry with two accretion columns rotating with the star, and a single accretion flow synchronized with the orbital motion of the hypothetical companion; the second scenario is more consistent with the observed properties of EX Lup. In this scenario, the companion's mass would fall into the brown dwarf desert, which, together with the unusually small separation of 0.06 au would make EX Lup a unique binary system. The companion also has interesting implications on the physical mechanisms responsible for triggering the outburstA.S.A. acknowledges support of the Spanish MICINN/MINECO “Ramón y Cajal” program, grant number RYC-2010-06164, and the action “Proyectos de Investigación fundamental no orientada”, grant number AYA2012-35008. This work was partly supported by the grant OTKA K101393 of the Hungarian Scientific Research FundESODepartamento de Física TeóricaFacultad de Ciencias20142014-01-01research articlehttp://purl.org/coar/resource_type/c_2df8fbb1VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10486/665162https://dx.doi.org/10.1051/0004-6361/201322428reponame:Biblos-e Archivo. Repositorio Institucional de la UAMinstname:Universidad Autónoma de MadridInglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:repositorio.uam.es:10486/6651622026-06-23T12:46:27Z
dc.title.none.fl_str_mv Radial velocity variations in the young eruptive star EX Lupi*'**
title Radial velocity variations in the young eruptive star EX Lupi*'**
spellingShingle Radial velocity variations in the young eruptive star EX Lupi*'**
Mohler-Fischer, Maren
Circumstellar matter
Infrared: stars
Stars: formation
Stars: individual: EX Lupi
Techniques: radial velocities
Física
title_short Radial velocity variations in the young eruptive star EX Lupi*'**
title_full Radial velocity variations in the young eruptive star EX Lupi*'**
title_fullStr Radial velocity variations in the young eruptive star EX Lupi*'**
title_full_unstemmed Radial velocity variations in the young eruptive star EX Lupi*'**
title_sort Radial velocity variations in the young eruptive star EX Lupi*'**
dc.creator.none.fl_str_mv Mohler-Fischer, Maren
Sicilia-Aguilar, Aurora
Ábrahám, P.
Curé, Michel
Launhardt, Ralf
Moór, Attila
Müller, André Frotta
Kóspál, Á.
Henning, Th.
Kiss, Cs.
author Mohler-Fischer, Maren
author_facet Mohler-Fischer, Maren
Sicilia-Aguilar, Aurora
Ábrahám, P.
Curé, Michel
Launhardt, Ralf
Moór, Attila
Müller, André Frotta
Kóspál, Á.
Henning, Th.
Kiss, Cs.
author_role author
author2 Sicilia-Aguilar, Aurora
Ábrahám, P.
Curé, Michel
Launhardt, Ralf
Moór, Attila
Müller, André Frotta
Kóspál, Á.
Henning, Th.
Kiss, Cs.
author2_role author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Departamento de Física Teórica
Facultad de Ciencias
dc.subject.none.fl_str_mv Circumstellar matter
Infrared: stars
Stars: formation
Stars: individual: EX Lupi
Techniques: radial velocities
Física
topic Circumstellar matter
Infrared: stars
Stars: formation
Stars: individual: EX Lupi
Techniques: radial velocities
Física
description Astronomy and Astrophysics 561 (2014): A61 reproduced with permission from Astronomy & Astrophysics
publishDate 2014
dc.date.none.fl_str_mv 2014
2014-01-01
dc.type.none.fl_str_mv research article
http://purl.org/coar/resource_type/c_2df8fbb1
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10486/665162
https://dx.doi.org/10.1051/0004-6361/201322428
url http://hdl.handle.net/10486/665162
https://dx.doi.org/10.1051/0004-6361/201322428
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv ESO
publisher.none.fl_str_mv ESO
dc.source.none.fl_str_mv reponame:Biblos-e Archivo. Repositorio Institucional de la UAM
instname:Universidad Autónoma de Madrid
instname_str Universidad Autónoma de Madrid
reponame_str Biblos-e Archivo. Repositorio Institucional de la UAM
collection Biblos-e Archivo. Repositorio Institucional de la UAM
repository.name.fl_str_mv
repository.mail.fl_str_mv
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