The 2014-2017 outburst of the young star ASASSN-13db

A time-resolved picture of a very low-mass star between EXors and FUors

Aurora Sicilia Aguilar (Lead / Corresponding author), A Oprandi, D. Froebrich, M. Fang, J. L. Prieto, K. Stanek, A. Scholz, C. S. Kochanek, Th. Henning, R. Gredel, Thomas W. S. Holoien, M. Rabus, B. J. Shappee, S. J. Billington, Justyn Campbell-White, T. J. Zegmott

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Abstract

Context: Accretion outbursts are key elements in star formation. ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted until February 2017.

Aims: We explore the photometric and spectroscopic behavior of ASASSN-13db during the 2014-2017 outburst.

Methods: We use high- and low-resolution spectroscopy and time-resolved photometry from the ASAS-SN survey, the LCOGT and the Beacon Observatory to study the lightcurve of ASASSN-13db and the dynamical and physical properties of the accretion flow.

Results: The 2014-2017 outburst lasted for nearly 800 days. A 4.15d period in the lightcurve likely corresponds to rotational modulation of a star with hot spot(s). The spectra show multiple emission lines with variable inverse P-Cygni profiles and a highly variable blueshifted absorption below the continuum. Line ratios from metallic emission lines (Fe I/Fe II, Ti I/Ti II) suggest temperatures of ∼5800-6000 K in the accretion flow.

Conclusions: Photometrically and spectroscopically, the 2014-2017 event displays an intermediate behavior between EXors and FUors. The accretion rate (M˙ =1-3×10−7M /yr), about 2 orders of magnitude higher than the accretion rate in quiescence, is not significantly different from the accretion rate observed in 2013. The absorption features in the spectra suggest that the system is viewed at a high angle and drives a powerful, non-axisymmetric wind, maybe related to magnetic reconnection. The properties of ASASSN-13db suggest that temperatures lower than those for solar-type stars are needed for modeling accretion in very low-mass systems. Finally, the rotational modulation during the outburst reveals that accretion-related structures settled after the begining of the outburst and can be relatively stable and long-lived. Our work also demonstrates the power of time-resolved photometry and spectroscopy to explore the properties of variable and outbursting stars.
Original languageEnglish
Article numberA127
Number of pages27
JournalAstronomy and Astrophysics
Volume607
Early online date24 Nov 2017
DOIs
Publication statusPublished - 24 Nov 2017

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outburst
accretion
stars
photometry
Advanced Solid-State Array Spectroradiometer
spectroscopy
young
modulation
beacons
protoplanetary disks
variable stars
star formation
hot spot
observatories
observatory
physical property
physical properties
continuums
high resolution
profiles

Keywords

  • stars: pre-main sequence
  • stars: individual (ASASSN-13db, SDSS J051011.01-032826.2)
  • stars: variability
  • protoplanetary disks
  • accretion
  • spectroscopic
  • stars:low-mass

Cite this

Sicilia Aguilar, Aurora ; Oprandi, A ; Froebrich, D. ; Fang, M. ; Prieto, J. L. ; Stanek, K. ; Scholz, A. ; Kochanek, C. S. ; Henning, Th. ; Gredel, R. ; Holoien, Thomas W. S. ; Rabus, M. ; Shappee, B. J. ; Billington, S. J. ; Campbell-White, Justyn ; Zegmott, T. J. . / The 2014-2017 outburst of the young star ASASSN-13db : A time-resolved picture of a very low-mass star between EXors and FUors . In: Astronomy and Astrophysics. 2017 ; Vol. 607.
@article{080e0e546a214679bfeeaae7c560af14,
title = "The 2014-2017 outburst of the young star ASASSN-13db: A time-resolved picture of a very low-mass star between EXors and FUors",
abstract = "Context: Accretion outbursts are key elements in star formation. ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted until February 2017. Aims: We explore the photometric and spectroscopic behavior of ASASSN-13db during the 2014-2017 outburst. Methods: We use high- and low-resolution spectroscopy and time-resolved photometry from the ASAS-SN survey, the LCOGT and the Beacon Observatory to study the lightcurve of ASASSN-13db and the dynamical and physical properties of the accretion flow. Results: The 2014-2017 outburst lasted for nearly 800 days. A 4.15d period in the lightcurve likely corresponds to rotational modulation of a star with hot spot(s). The spectra show multiple emission lines with variable inverse P-Cygni profiles and a highly variable blueshifted absorption below the continuum. Line ratios from metallic emission lines (Fe I/Fe II, Ti I/Ti II) suggest temperatures of ∼5800-6000 K in the accretion flow. Conclusions: Photometrically and spectroscopically, the 2014-2017 event displays an intermediate behavior between EXors and FUors. The accretion rate (M˙ =1-3×10−7M /yr), about 2 orders of magnitude higher than the accretion rate in quiescence, is not significantly different from the accretion rate observed in 2013. The absorption features in the spectra suggest that the system is viewed at a high angle and drives a powerful, non-axisymmetric wind, maybe related to magnetic reconnection. The properties of ASASSN-13db suggest that temperatures lower than those for solar-type stars are needed for modeling accretion in very low-mass systems. Finally, the rotational modulation during the outburst reveals that accretion-related structures settled after the begining of the outburst and can be relatively stable and long-lived. Our work also demonstrates the power of time-resolved photometry and spectroscopy to explore the properties of variable and outbursting stars.",
keywords = "stars: pre-main sequence, stars: individual (ASASSN-13db, SDSS J051011.01-032826.2), stars: variability, protoplanetary disks, accretion, spectroscopic, stars:low-mass",
author = "{Sicilia Aguilar}, Aurora and A Oprandi and D. Froebrich and M. Fang and Prieto, {J. L.} and K. Stanek and A. Scholz and Kochanek, {C. S.} and Th. Henning and R. Gredel and Holoien, {Thomas W. S.} and M. Rabus and Shappee, {B. J.} and Billington, {S. J.} and Justyn Campbell-White and Zegmott, {T. J.}",
note = "A.O. acknowledges support by the Royal Astronomical Society via a 2016 Summer Fellowship under the supervision of A.S.A. Support for J.L.P. is provided in part by FONDECYT through the grant 1151445 and by the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. T.W.-S.H. is supported by the DOE Computational Science Graduate Fellowship, grant number DE-FG02-97ER25308. B.J.S. is supported by NASA through Hubble Fellowship grant HST-HF-51348.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555.",
year = "2017",
month = "11",
day = "24",
doi = "10.1051/0004-6361/201731263",
language = "English",
volume = "607",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

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Sicilia Aguilar, A, Oprandi, A, Froebrich, D, Fang, M, Prieto, JL, Stanek, K, Scholz, A, Kochanek, CS, Henning, T, Gredel, R, Holoien, TWS, Rabus, M, Shappee, BJ, Billington, SJ, Campbell-White, J & Zegmott, TJ 2017, 'The 2014-2017 outburst of the young star ASASSN-13db: A time-resolved picture of a very low-mass star between EXors and FUors ', Astronomy and Astrophysics, vol. 607, A127. https://doi.org/10.1051/0004-6361/201731263

The 2014-2017 outburst of the young star ASASSN-13db : A time-resolved picture of a very low-mass star between EXors and FUors . / Sicilia Aguilar, Aurora (Lead / Corresponding author); Oprandi, A; Froebrich, D. ; Fang, M.; Prieto, J. L.; Stanek, K. ; Scholz, A.; Kochanek, C. S.; Henning, Th.; Gredel, R. ; Holoien, Thomas W. S.; Rabus, M. ; Shappee, B. J.; Billington, S. J. ; Campbell-White, Justyn; Zegmott, T. J. .

In: Astronomy and Astrophysics, Vol. 607, A127, 24.11.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The 2014-2017 outburst of the young star ASASSN-13db

T2 - A time-resolved picture of a very low-mass star between EXors and FUors

AU - Sicilia Aguilar, Aurora

AU - Oprandi, A

AU - Froebrich, D.

AU - Fang, M.

AU - Prieto, J. L.

AU - Stanek, K.

AU - Scholz, A.

AU - Kochanek, C. S.

AU - Henning, Th.

AU - Gredel, R.

AU - Holoien, Thomas W. S.

AU - Rabus, M.

AU - Shappee, B. J.

AU - Billington, S. J.

AU - Campbell-White, Justyn

AU - Zegmott, T. J.

N1 - A.O. acknowledges support by the Royal Astronomical Society via a 2016 Summer Fellowship under the supervision of A.S.A. Support for J.L.P. is provided in part by FONDECYT through the grant 1151445 and by the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. T.W.-S.H. is supported by the DOE Computational Science Graduate Fellowship, grant number DE-FG02-97ER25308. B.J.S. is supported by NASA through Hubble Fellowship grant HST-HF-51348.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555.

PY - 2017/11/24

Y1 - 2017/11/24

N2 - Context: Accretion outbursts are key elements in star formation. ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted until February 2017. Aims: We explore the photometric and spectroscopic behavior of ASASSN-13db during the 2014-2017 outburst. Methods: We use high- and low-resolution spectroscopy and time-resolved photometry from the ASAS-SN survey, the LCOGT and the Beacon Observatory to study the lightcurve of ASASSN-13db and the dynamical and physical properties of the accretion flow. Results: The 2014-2017 outburst lasted for nearly 800 days. A 4.15d period in the lightcurve likely corresponds to rotational modulation of a star with hot spot(s). The spectra show multiple emission lines with variable inverse P-Cygni profiles and a highly variable blueshifted absorption below the continuum. Line ratios from metallic emission lines (Fe I/Fe II, Ti I/Ti II) suggest temperatures of ∼5800-6000 K in the accretion flow. Conclusions: Photometrically and spectroscopically, the 2014-2017 event displays an intermediate behavior between EXors and FUors. The accretion rate (M˙ =1-3×10−7M /yr), about 2 orders of magnitude higher than the accretion rate in quiescence, is not significantly different from the accretion rate observed in 2013. The absorption features in the spectra suggest that the system is viewed at a high angle and drives a powerful, non-axisymmetric wind, maybe related to magnetic reconnection. The properties of ASASSN-13db suggest that temperatures lower than those for solar-type stars are needed for modeling accretion in very low-mass systems. Finally, the rotational modulation during the outburst reveals that accretion-related structures settled after the begining of the outburst and can be relatively stable and long-lived. Our work also demonstrates the power of time-resolved photometry and spectroscopy to explore the properties of variable and outbursting stars.

AB - Context: Accretion outbursts are key elements in star formation. ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted until February 2017. Aims: We explore the photometric and spectroscopic behavior of ASASSN-13db during the 2014-2017 outburst. Methods: We use high- and low-resolution spectroscopy and time-resolved photometry from the ASAS-SN survey, the LCOGT and the Beacon Observatory to study the lightcurve of ASASSN-13db and the dynamical and physical properties of the accretion flow. Results: The 2014-2017 outburst lasted for nearly 800 days. A 4.15d period in the lightcurve likely corresponds to rotational modulation of a star with hot spot(s). The spectra show multiple emission lines with variable inverse P-Cygni profiles and a highly variable blueshifted absorption below the continuum. Line ratios from metallic emission lines (Fe I/Fe II, Ti I/Ti II) suggest temperatures of ∼5800-6000 K in the accretion flow. Conclusions: Photometrically and spectroscopically, the 2014-2017 event displays an intermediate behavior between EXors and FUors. The accretion rate (M˙ =1-3×10−7M /yr), about 2 orders of magnitude higher than the accretion rate in quiescence, is not significantly different from the accretion rate observed in 2013. The absorption features in the spectra suggest that the system is viewed at a high angle and drives a powerful, non-axisymmetric wind, maybe related to magnetic reconnection. The properties of ASASSN-13db suggest that temperatures lower than those for solar-type stars are needed for modeling accretion in very low-mass systems. Finally, the rotational modulation during the outburst reveals that accretion-related structures settled after the begining of the outburst and can be relatively stable and long-lived. Our work also demonstrates the power of time-resolved photometry and spectroscopy to explore the properties of variable and outbursting stars.

KW - stars: pre-main sequence

KW - stars: individual (ASASSN-13db, SDSS J051011.01-032826.2)

KW - stars: variability

KW - protoplanetary disks

KW - accretion

KW - spectroscopic

KW - stars:low-mass

UR - https://arxiv.org/abs/1708.02010

U2 - 10.1051/0004-6361/201731263

DO - 10.1051/0004-6361/201731263

M3 - Article

VL - 607

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A127

ER -