TY - JOUR
T1 - An Exceptional Dimming Event for a Massive, Cool Supergiant in M51
AU - Jencson, Jacob E.
AU - Sand, David J.
AU - Andrews, Jennifer E.
AU - Smith, Nathan
AU - Pearson, Jeniveve
AU - Strader, Jay
AU - Valenti, Stefano
AU - Beasor, Emma R.
AU - Rothberg, Barry
N1 - Funding Information:
Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with programs #HST-GO-15645, 16508, 10452, 14704, 12490, and 12762. Support for program #HST-GO-15645 and #HST-GO-16508 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.
Funding Information:
Time-domain research by D.J.S. is also supported by NSF grant Nos. AST-1821987, 1813466, 1908972, & 2108032, and by the Heising-Simons Foundation under grant #2020-1864. J.S. acknowledges support from NASA grant No. HST-GO-15645.003-A and the Packard Foundation. Research by S.V. is supported by NSF grant Nos. AST-1813176 and AST-2008108. E.R.B. is supported by NASA through a Hubble Fellowship grant No. HST-HF2-51428 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555.
Funding Information:
Based on observations obtained at the Gemini Observatory (Programs GN-2005A-Q-49 and GN-2021A-DD-101), which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea).
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/5/1
Y1 - 2022/5/1
N2 - We present the discovery of an exceptional dimming event in a cool supergiant star in the Local Volume spiral M51. The star, dubbed M51-DS1, was found as part of a Hubble Space Telescope (HST) search for failed supernovae (SNe). The supergiant, which is plausibly associated with a very young (≲26 Myr) stellar population, showed clear variability (amplitude ΔF814W ≈ 0.7 mag) in numerous HST images obtained between 1995 and 2016, before suddenly dimming by >2 mag in F814W sometime between late 2017 and mid-2019. In follow-up data from 2021, the star rebrightened, ruling out a failed supernova. Prior to its near-disappearance, the star was luminous and red (M F814W ≲2 - 7.6 mag, F606W - F814W = 1.9-2.2 mag). Modeling of the pre-dimming spectral energy distribution of the star favors a highly reddened, very luminous ( log[L/L⊙]=5.4 -5.7) star with T eff ≈ 3700-4700 K, indicative of a cool yellow or post-red supergiant (RSG) with an initial mass of ≈26-40 M ⊙. However, the local interstellar extinction and circumstellar extinction are uncertain, and could be lower: the near-IR colors are consistent with an RSG, which would be cooler (T eff ≲2 3700 K) and slightly less luminous ( log[L/L⊙]=5.2 -5.3), giving an inferred initial mass of ≈19-22 M ⊙. In either case, the dimming may be explained by a rare episode of enhanced mass loss that temporarily obscures the star, potentially a more extreme counterpart to the 2019-2020 "Great Dimming"of Betelgeuse. Given the emerging evidence that massive evolved stars commonly exhibit variability that can mimic a disappearing star, our work highlights a substantial challenge in identifying true failed SNe.
AB - We present the discovery of an exceptional dimming event in a cool supergiant star in the Local Volume spiral M51. The star, dubbed M51-DS1, was found as part of a Hubble Space Telescope (HST) search for failed supernovae (SNe). The supergiant, which is plausibly associated with a very young (≲26 Myr) stellar population, showed clear variability (amplitude ΔF814W ≈ 0.7 mag) in numerous HST images obtained between 1995 and 2016, before suddenly dimming by >2 mag in F814W sometime between late 2017 and mid-2019. In follow-up data from 2021, the star rebrightened, ruling out a failed supernova. Prior to its near-disappearance, the star was luminous and red (M F814W ≲2 - 7.6 mag, F606W - F814W = 1.9-2.2 mag). Modeling of the pre-dimming spectral energy distribution of the star favors a highly reddened, very luminous ( log[L/L⊙]=5.4 -5.7) star with T eff ≈ 3700-4700 K, indicative of a cool yellow or post-red supergiant (RSG) with an initial mass of ≈26-40 M ⊙. However, the local interstellar extinction and circumstellar extinction are uncertain, and could be lower: the near-IR colors are consistent with an RSG, which would be cooler (T eff ≲2 3700 K) and slightly less luminous ( log[L/L⊙]=5.2 -5.3), giving an inferred initial mass of ≈19-22 M ⊙. In either case, the dimming may be explained by a rare episode of enhanced mass loss that temporarily obscures the star, potentially a more extreme counterpart to the 2019-2020 "Great Dimming"of Betelgeuse. Given the emerging evidence that massive evolved stars commonly exhibit variability that can mimic a disappearing star, our work highlights a substantial challenge in identifying true failed SNe.
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U2 - 10.3847/1538-4357/ac626c
DO - 10.3847/1538-4357/ac626c
M3 - Article
AN - SCOPUS:85130442408
SN - 0004-637X
VL - 930
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 81
ER -