Massive star mergers and the recent transient in NGC 4490

A more massive cousin of V838 Mon and V1309 Sco

Nathan Smith, Jennifer E. Andrews, Schuyler D. Van Dyk, Jon C. Mauerhan, Mansi M. Kasliwal, Howard E. Bond, Alexei V. Filippenko, Kelsey I. Clubb, Melissa L. Graham, Daniel A. Perley, Jacob Jencson, John Bally, Leonardo Ubeda, Elena Sabbi

Research output: Contribution to journalArticle

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Abstract

The Galactic transient V1309 Sco was the result of a merger in a low-mass star system, while V838 Mon was thought to be a similar merger event from a more massive B-type progenitor. In this paper, we study a recent optical and infrared (IR) transient discovered in the nearby galaxy NGC4490 named NGC4490-OT2011 (NGC 4490-OT hereafter), which appeared similar to these merger events (unobscured progenitor, irregular multi-peaked light curve, increasingly red colour, similar optical spectrum, IR excess at late times), but which had a higher peak luminosity and longer duration in outburst. NGC4490-OT has less in common with the class of SN 2008S-like transients. A progenitor detected in pre-eruption Hubble Space Telescope (HST) images, combined with upper limits in the IR, requires a luminous and blue progenitor that has faded in late-time HST images. The same source was detected by Spitzer and groundbased data as a luminous IR (2-5 μm) transient, indicating a transition to a self-obscured state qualitatively similar to the evolution seen in other stellar mergers and in luminous blue variables. The post-outburst dust-obscured source is too luminous and too warm at late times to be explained with an IR echo, suggesting that the object survived the event. The luminosity of the enshrouded IR source is similar to that of the progenitor. Compared to proposed merger events, the more massive progenitor of NGC4490-OT seems to extend a correlation between stellar mass and peak luminosity, and may suggest that both of these correlate with duration. We show that spectra of NGC4490-OT and V838 Mon also resemble light-echo spectra of η Car, prompting us to speculate that η Car may be an extreme extension of this phenomenon.

Original languageEnglish (US)
Pages (from-to)950-962
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume458
Issue number1
DOIs
StatePublished - Feb 22 2016

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massive stars
merger
luminosity
Hubble Space Telescope
outburst
automobile
echoes
stellar mass
volcanic eruptions
light curve
optical spectrum
volcanic eruption
dust
galaxies
color
stars

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Smith, Nathan ; Andrews, Jennifer E. ; Van Dyk, Schuyler D. ; Mauerhan, Jon C. ; Kasliwal, Mansi M. ; Bond, Howard E. ; Filippenko, Alexei V. ; Clubb, Kelsey I. ; Graham, Melissa L. ; Perley, Daniel A. ; Jencson, Jacob ; Bally, John ; Ubeda, Leonardo ; Sabbi, Elena. / Massive star mergers and the recent transient in NGC 4490 : A more massive cousin of V838 Mon and V1309 Sco. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 458, No. 1. pp. 950-962.
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title = "Massive star mergers and the recent transient in NGC 4490: A more massive cousin of V838 Mon and V1309 Sco",
abstract = "The Galactic transient V1309 Sco was the result of a merger in a low-mass star system, while V838 Mon was thought to be a similar merger event from a more massive B-type progenitor. In this paper, we study a recent optical and infrared (IR) transient discovered in the nearby galaxy NGC4490 named NGC4490-OT2011 (NGC 4490-OT hereafter), which appeared similar to these merger events (unobscured progenitor, irregular multi-peaked light curve, increasingly red colour, similar optical spectrum, IR excess at late times), but which had a higher peak luminosity and longer duration in outburst. NGC4490-OT has less in common with the class of SN 2008S-like transients. A progenitor detected in pre-eruption Hubble Space Telescope (HST) images, combined with upper limits in the IR, requires a luminous and blue progenitor that has faded in late-time HST images. The same source was detected by Spitzer and groundbased data as a luminous IR (2-5 μm) transient, indicating a transition to a self-obscured state qualitatively similar to the evolution seen in other stellar mergers and in luminous blue variables. The post-outburst dust-obscured source is too luminous and too warm at late times to be explained with an IR echo, suggesting that the object survived the event. The luminosity of the enshrouded IR source is similar to that of the progenitor. Compared to proposed merger events, the more massive progenitor of NGC4490-OT seems to extend a correlation between stellar mass and peak luminosity, and may suggest that both of these correlate with duration. We show that spectra of NGC4490-OT and V838 Mon also resemble light-echo spectra of η Car, prompting us to speculate that η Car may be an extreme extension of this phenomenon.",
author = "Nathan Smith and Andrews, {Jennifer E.} and {Van Dyk}, {Schuyler D.} and Mauerhan, {Jon C.} and Kasliwal, {Mansi M.} and Bond, {Howard E.} and Filippenko, {Alexei V.} and Clubb, {Kelsey I.} and Graham, {Melissa L.} and Perley, {Daniel A.} and Jacob Jencson and John Bally and Leonardo Ubeda and Elena Sabbi",
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Smith, N, Andrews, JE, Van Dyk, SD, Mauerhan, JC, Kasliwal, MM, Bond, HE, Filippenko, AV, Clubb, KI, Graham, ML, Perley, DA, Jencson, J, Bally, J, Ubeda, L & Sabbi, E 2016, 'Massive star mergers and the recent transient in NGC 4490: A more massive cousin of V838 Mon and V1309 Sco', Monthly Notices of the Royal Astronomical Society, vol. 458, no. 1, pp. 950-962. https://doi.org/10.1093/mnras/stw219

Massive star mergers and the recent transient in NGC 4490 : A more massive cousin of V838 Mon and V1309 Sco. / Smith, Nathan; Andrews, Jennifer E.; Van Dyk, Schuyler D.; Mauerhan, Jon C.; Kasliwal, Mansi M.; Bond, Howard E.; Filippenko, Alexei V.; Clubb, Kelsey I.; Graham, Melissa L.; Perley, Daniel A.; Jencson, Jacob; Bally, John; Ubeda, Leonardo; Sabbi, Elena.

In: Monthly Notices of the Royal Astronomical Society, Vol. 458, No. 1, 22.02.2016, p. 950-962.

Research output: Contribution to journalArticle

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T1 - Massive star mergers and the recent transient in NGC 4490

T2 - A more massive cousin of V838 Mon and V1309 Sco

AU - Smith, Nathan

AU - Andrews, Jennifer E.

AU - Van Dyk, Schuyler D.

AU - Mauerhan, Jon C.

AU - Kasliwal, Mansi M.

AU - Bond, Howard E.

AU - Filippenko, Alexei V.

AU - Clubb, Kelsey I.

AU - Graham, Melissa L.

AU - Perley, Daniel A.

AU - Jencson, Jacob

AU - Bally, John

AU - Ubeda, Leonardo

AU - Sabbi, Elena

PY - 2016/2/22

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N2 - The Galactic transient V1309 Sco was the result of a merger in a low-mass star system, while V838 Mon was thought to be a similar merger event from a more massive B-type progenitor. In this paper, we study a recent optical and infrared (IR) transient discovered in the nearby galaxy NGC4490 named NGC4490-OT2011 (NGC 4490-OT hereafter), which appeared similar to these merger events (unobscured progenitor, irregular multi-peaked light curve, increasingly red colour, similar optical spectrum, IR excess at late times), but which had a higher peak luminosity and longer duration in outburst. NGC4490-OT has less in common with the class of SN 2008S-like transients. A progenitor detected in pre-eruption Hubble Space Telescope (HST) images, combined with upper limits in the IR, requires a luminous and blue progenitor that has faded in late-time HST images. The same source was detected by Spitzer and groundbased data as a luminous IR (2-5 μm) transient, indicating a transition to a self-obscured state qualitatively similar to the evolution seen in other stellar mergers and in luminous blue variables. The post-outburst dust-obscured source is too luminous and too warm at late times to be explained with an IR echo, suggesting that the object survived the event. The luminosity of the enshrouded IR source is similar to that of the progenitor. Compared to proposed merger events, the more massive progenitor of NGC4490-OT seems to extend a correlation between stellar mass and peak luminosity, and may suggest that both of these correlate with duration. We show that spectra of NGC4490-OT and V838 Mon also resemble light-echo spectra of η Car, prompting us to speculate that η Car may be an extreme extension of this phenomenon.

AB - The Galactic transient V1309 Sco was the result of a merger in a low-mass star system, while V838 Mon was thought to be a similar merger event from a more massive B-type progenitor. In this paper, we study a recent optical and infrared (IR) transient discovered in the nearby galaxy NGC4490 named NGC4490-OT2011 (NGC 4490-OT hereafter), which appeared similar to these merger events (unobscured progenitor, irregular multi-peaked light curve, increasingly red colour, similar optical spectrum, IR excess at late times), but which had a higher peak luminosity and longer duration in outburst. NGC4490-OT has less in common with the class of SN 2008S-like transients. A progenitor detected in pre-eruption Hubble Space Telescope (HST) images, combined with upper limits in the IR, requires a luminous and blue progenitor that has faded in late-time HST images. The same source was detected by Spitzer and groundbased data as a luminous IR (2-5 μm) transient, indicating a transition to a self-obscured state qualitatively similar to the evolution seen in other stellar mergers and in luminous blue variables. The post-outburst dust-obscured source is too luminous and too warm at late times to be explained with an IR echo, suggesting that the object survived the event. The luminosity of the enshrouded IR source is similar to that of the progenitor. Compared to proposed merger events, the more massive progenitor of NGC4490-OT seems to extend a correlation between stellar mass and peak luminosity, and may suggest that both of these correlate with duration. We show that spectra of NGC4490-OT and V838 Mon also resemble light-echo spectra of η Car, prompting us to speculate that η Car may be an extreme extension of this phenomenon.

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