The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations
The binarity of red supergiants (RSGs) influences their evolution and the fate of supernovae. We investigate the binary fraction of RSGs in the Andromeda galaxy (M31) and Triangulum galaxy (M33) using photometry from the Hubble Space Telescope (HST), which offers high spatial resolution to resolve m...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ade156 |
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| author | Min Dai Shu Wang Biwei Jiang Ying Li |
| author_facet | Min Dai Shu Wang Biwei Jiang Ying Li |
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| description | The binarity of red supergiants (RSGs) influences their evolution and the fate of supernovae. We investigate the binary fraction of RSGs in the Andromeda galaxy (M31) and Triangulum galaxy (M33) using photometry from the Hubble Space Telescope (HST), which offers high spatial resolution to resolve more RSGs. A preliminary step involves identifying a reliable and complete RSG sample using the F110W − F160W versus F160W diagram, yielding 2612 RSGs from the Panchromatic Hubble Andromeda Treasury (PHAT) survey of M31 and 3294 RSGs from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region survey of M33. These samples suggest total RSG populations in M31 and M33 of 6563 and 7572, respectively. These estimates significantly exceed previous ones from the ground-based observations, an increase attributed to the superior spatial resolution of the HST. The stellar parameters of these RSGs, including effective temperature ( T _eff ), radius ( R ), and luminosity ( L ), are derived by fitting their spectral energy distribution (SED) across optical and near-infrared bands. Binary candidates are identified by detecting ultraviolet excesses in their SEDs compared to the single-star RSG model prediction. The binary fraction is determined to be 33.4% ± 0.9% for M31 and 30.9% ± 0.8% for M33. For more luminous RSGs with log L / L _⊙ > 4.0, the binary fraction decreases to 31.6% ± 1.9% in M31 and increases to 34.7% ± 1.8% in M33, respectively. These results are in good agreement with predictions from the Binary Population and Spectral Synthesis binary evolution model. |
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| institution | DOAJ |
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| publishDate | 2025-01-01 |
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| spelling | doaj-art-dd842f3b2ef843e09be1879306d595ab2025-08-20T03:11:37ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198816010.3847/1538-4357/ade156The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST ObservationsMin Dai0https://orcid.org/0009-0005-3951-3625Shu Wang1https://orcid.org/0000-0003-4489-9794Biwei Jiang2https://orcid.org/0000-0003-3168-2617Ying Li3https://orcid.org/0009-0001-5020-4269School of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of China ; bjiang@bnu.edu.cn; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; shuwang@nao.cas.cnSchool of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of China ; bjiang@bnu.edu.cn; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaSchool of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of China ; bjiang@bnu.edu.cn; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaThe binarity of red supergiants (RSGs) influences their evolution and the fate of supernovae. We investigate the binary fraction of RSGs in the Andromeda galaxy (M31) and Triangulum galaxy (M33) using photometry from the Hubble Space Telescope (HST), which offers high spatial resolution to resolve more RSGs. A preliminary step involves identifying a reliable and complete RSG sample using the F110W − F160W versus F160W diagram, yielding 2612 RSGs from the Panchromatic Hubble Andromeda Treasury (PHAT) survey of M31 and 3294 RSGs from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region survey of M33. These samples suggest total RSG populations in M31 and M33 of 6563 and 7572, respectively. These estimates significantly exceed previous ones from the ground-based observations, an increase attributed to the superior spatial resolution of the HST. The stellar parameters of these RSGs, including effective temperature ( T _eff ), radius ( R ), and luminosity ( L ), are derived by fitting their spectral energy distribution (SED) across optical and near-infrared bands. Binary candidates are identified by detecting ultraviolet excesses in their SEDs compared to the single-star RSG model prediction. The binary fraction is determined to be 33.4% ± 0.9% for M31 and 30.9% ± 0.8% for M33. For more luminous RSGs with log L / L _⊙ > 4.0, the binary fraction decreases to 31.6% ± 1.9% in M31 and increases to 34.7% ± 1.8% in M33, respectively. These results are in good agreement with predictions from the Binary Population and Spectral Synthesis binary evolution model.https://doi.org/10.3847/1538-4357/ade156Red supergiant starsBinary starsSpectral energy distributionAndromeda galaxyTriangulum Galaxy |
| spellingShingle | Min Dai Shu Wang Biwei Jiang Ying Li The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations The Astrophysical Journal Red supergiant stars Binary stars Spectral energy distribution Andromeda galaxy Triangulum Galaxy |
| title | The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations |
| title_full | The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations |
| title_fullStr | The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations |
| title_full_unstemmed | The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations |
| title_short | The Samples and Binary Fractions of Red Supergiants in M31 and M33 by the HST Observations |
| title_sort | samples and binary fractions of red supergiants in m31 and m33 by the hst observations |
| topic | Red supergiant stars Binary stars Spectral energy distribution Andromeda galaxy Triangulum Galaxy |
| url | https://doi.org/10.3847/1538-4357/ade156 |
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