Near-infrared spectroscopy of EX Lupi in outburst

Á Kóspál, P. Ábrahám, M. Goto, Zs Regály, C. P. Dullemond, Th Henning, A. Juhász, A. Sicilia-Aguilar, M. Van Den Ancker

Research output: Article

19 Citations (Scopus)

Abstract

EX Lup is the prototype of the EXor class of young eruptive stars: objects showing repetitive brightenings due to increased accretion from the circumstellar disk to the star. In this paper, we report on medium-resolution near-infrared spectroscopy of EX Lup taken during its extreme outburst in 2008, as well as numerical modeling with the aim of determining the physical conditions around the star. We detect emission lines from atomic hydrogen, helium, and metals, as well as first overtone bandhead emission from carbon monoxide. Our results indicate that the emission lines are originating from gas located in a dust-free region within ≈0.2 AU of the star. The profile of the CO bandhead indicates that the CO gas has a temperature of 2500K and is located in the inner edge of the disk or in the outer parts of funnel flows. The atomic metals are probably colocated with the CO. Some metallic lines are fluorescently excited, suggesting direct exposure to ultraviolet photons. The Brackett series indicates emission from hot (10,000K) and optically thin gas. The hydrogen lines display a strong spectro-astrometric signal, suggesting that the hydrogen emission is probably not coming from an equatorial boundary layer; a funnel flow or disk wind origin is more likely. This picture is broadly consistent with the standard magnetospheric accretion model usually assumed for normally accreting TTauri stars. Our results also set constraints on the eruption mechanism, supporting a model where material piles up around the corotation radius and episodically falls onto the star.

Original languageEnglish
Article number72
JournalAstrophysical Journal
Volume736
Issue number1
DOIs
Publication statusPublished - júl. 20 2011

Fingerprint

infrared spectroscopy
outburst
near infrared
stars
hydrogen
funnels
accretion
gas
gases
metal
corotation
carbon monoxide
helium
piles
pile
volcanic eruptions
metals
volcanic eruption
boundary layer
boundary layers

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Kóspál, Á., Ábrahám, P., Goto, M., Regály, Z., Dullemond, C. P., Henning, T., ... Van Den Ancker, M. (2011). Near-infrared spectroscopy of EX Lupi in outburst. Astrophysical Journal, 736(1), [72]. https://doi.org/10.1088/0004-637X/736/1/72

Near-infrared spectroscopy of EX Lupi in outburst. / Kóspál, Á; Ábrahám, P.; Goto, M.; Regály, Zs; Dullemond, C. P.; Henning, Th; Juhász, A.; Sicilia-Aguilar, A.; Van Den Ancker, M.

In: Astrophysical Journal, Vol. 736, No. 1, 72, 20.07.2011.

Research output: Article

Kóspál, Á, Ábrahám, P, Goto, M, Regály, Z, Dullemond, CP, Henning, T, Juhász, A, Sicilia-Aguilar, A & Van Den Ancker, M 2011, 'Near-infrared spectroscopy of EX Lupi in outburst', Astrophysical Journal, vol. 736, no. 1, 72. https://doi.org/10.1088/0004-637X/736/1/72
Kóspál Á, Ábrahám P, Goto M, Regály Z, Dullemond CP, Henning T et al. Near-infrared spectroscopy of EX Lupi in outburst. Astrophysical Journal. 2011 júl. 20;736(1). 72. https://doi.org/10.1088/0004-637X/736/1/72
Kóspál, Á ; Ábrahám, P. ; Goto, M. ; Regály, Zs ; Dullemond, C. P. ; Henning, Th ; Juhász, A. ; Sicilia-Aguilar, A. ; Van Den Ancker, M. / Near-infrared spectroscopy of EX Lupi in outburst. In: Astrophysical Journal. 2011 ; Vol. 736, No. 1.
@article{adca91991b874cc1b4df4a9c9f187f0e,
title = "Near-infrared spectroscopy of EX Lupi in outburst",
abstract = "EX Lup is the prototype of the EXor class of young eruptive stars: objects showing repetitive brightenings due to increased accretion from the circumstellar disk to the star. In this paper, we report on medium-resolution near-infrared spectroscopy of EX Lup taken during its extreme outburst in 2008, as well as numerical modeling with the aim of determining the physical conditions around the star. We detect emission lines from atomic hydrogen, helium, and metals, as well as first overtone bandhead emission from carbon monoxide. Our results indicate that the emission lines are originating from gas located in a dust-free region within ≈0.2 AU of the star. The profile of the CO bandhead indicates that the CO gas has a temperature of 2500K and is located in the inner edge of the disk or in the outer parts of funnel flows. The atomic metals are probably colocated with the CO. Some metallic lines are fluorescently excited, suggesting direct exposure to ultraviolet photons. The Brackett series indicates emission from hot (10,000K) and optically thin gas. The hydrogen lines display a strong spectro-astrometric signal, suggesting that the hydrogen emission is probably not coming from an equatorial boundary layer; a funnel flow or disk wind origin is more likely. This picture is broadly consistent with the standard magnetospheric accretion model usually assumed for normally accreting TTauri stars. Our results also set constraints on the eruption mechanism, supporting a model where material piles up around the corotation radius and episodically falls onto the star.",
keywords = "infrared: stars, stars: activity, stars: individual (EX Lup), stars: pre-main sequence, techniques: spectroscopic",
author = "{\'A} K{\'o}sp{\'a}l and P. {\'A}brah{\'a}m and M. Goto and Zs Reg{\'a}ly and Dullemond, {C. P.} and Th Henning and A. Juh{\'a}sz and A. Sicilia-Aguilar and {Van Den Ancker}, M.",
year = "2011",
month = "7",
day = "20",
doi = "10.1088/0004-637X/736/1/72",
language = "English",
volume = "736",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Near-infrared spectroscopy of EX Lupi in outburst

AU - Kóspál, Á

AU - Ábrahám, P.

AU - Goto, M.

AU - Regály, Zs

AU - Dullemond, C. P.

AU - Henning, Th

AU - Juhász, A.

AU - Sicilia-Aguilar, A.

AU - Van Den Ancker, M.

PY - 2011/7/20

Y1 - 2011/7/20

N2 - EX Lup is the prototype of the EXor class of young eruptive stars: objects showing repetitive brightenings due to increased accretion from the circumstellar disk to the star. In this paper, we report on medium-resolution near-infrared spectroscopy of EX Lup taken during its extreme outburst in 2008, as well as numerical modeling with the aim of determining the physical conditions around the star. We detect emission lines from atomic hydrogen, helium, and metals, as well as first overtone bandhead emission from carbon monoxide. Our results indicate that the emission lines are originating from gas located in a dust-free region within ≈0.2 AU of the star. The profile of the CO bandhead indicates that the CO gas has a temperature of 2500K and is located in the inner edge of the disk or in the outer parts of funnel flows. The atomic metals are probably colocated with the CO. Some metallic lines are fluorescently excited, suggesting direct exposure to ultraviolet photons. The Brackett series indicates emission from hot (10,000K) and optically thin gas. The hydrogen lines display a strong spectro-astrometric signal, suggesting that the hydrogen emission is probably not coming from an equatorial boundary layer; a funnel flow or disk wind origin is more likely. This picture is broadly consistent with the standard magnetospheric accretion model usually assumed for normally accreting TTauri stars. Our results also set constraints on the eruption mechanism, supporting a model where material piles up around the corotation radius and episodically falls onto the star.

AB - EX Lup is the prototype of the EXor class of young eruptive stars: objects showing repetitive brightenings due to increased accretion from the circumstellar disk to the star. In this paper, we report on medium-resolution near-infrared spectroscopy of EX Lup taken during its extreme outburst in 2008, as well as numerical modeling with the aim of determining the physical conditions around the star. We detect emission lines from atomic hydrogen, helium, and metals, as well as first overtone bandhead emission from carbon monoxide. Our results indicate that the emission lines are originating from gas located in a dust-free region within ≈0.2 AU of the star. The profile of the CO bandhead indicates that the CO gas has a temperature of 2500K and is located in the inner edge of the disk or in the outer parts of funnel flows. The atomic metals are probably colocated with the CO. Some metallic lines are fluorescently excited, suggesting direct exposure to ultraviolet photons. The Brackett series indicates emission from hot (10,000K) and optically thin gas. The hydrogen lines display a strong spectro-astrometric signal, suggesting that the hydrogen emission is probably not coming from an equatorial boundary layer; a funnel flow or disk wind origin is more likely. This picture is broadly consistent with the standard magnetospheric accretion model usually assumed for normally accreting TTauri stars. Our results also set constraints on the eruption mechanism, supporting a model where material piles up around the corotation radius and episodically falls onto the star.

KW - infrared: stars

KW - stars: activity

KW - stars: individual (EX Lup)

KW - stars: pre-main sequence

KW - techniques: spectroscopic

UR - http://www.scopus.com/inward/record.url?scp=80051485374&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80051485374&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/736/1/72

DO - 10.1088/0004-637X/736/1/72

M3 - Article

AN - SCOPUS:80051485374

VL - 736

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 72

ER -