Disk in the Circumstellar Envelope of Carbon Mira V Cygni
Asymptotic giant branch (AGB) stars are the primary source of dust and complex molecules in the interstellar medium. The determination of outflow parameters is often hindered by the unknown geometry of the circumstellar environment, creating a demand for high-angular resolution observations. We use...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-3881/adaaf3 |
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| author | Boris S. Safonov Sergey G. Zheltoukhov Andrey M. Tatarnikov Ivan A. Strakhov Victor I. Shenavrin |
| author_facet | Boris S. Safonov Sergey G. Zheltoukhov Andrey M. Tatarnikov Ivan A. Strakhov Victor I. Shenavrin |
| author_sort | Boris S. Safonov |
| collection | DOAJ |
| description | Asymptotic giant branch (AGB) stars are the primary source of dust and complex molecules in the interstellar medium. The determination of outflow parameters is often hindered by the unknown geometry of the circumstellar environment, creating a demand for high-angular resolution observations. We use our near-infrared spectra and photometry of the carbon AGB star V Cyg, along with literature data, to construct its spectral energy distribution over a wide range of wavelengths. The dust envelope responsible for the infrared excess was also resolved in scattered polarized light at angular scales of 50–80 mas using differential speckle polarimetry. We present an interpretation of the thermal and scattered radiation of the dust using models of a spherical dusty outflow ( M _dust = 5.3 × 10 ^−7 M _⊙ ) and an inclined equatorial density enhancement, either in the form of a disk ( M _dust = 7.6 × 10 ^−3 M _⊕ ) or a torus ( M _dust = 5.7 × 10 ^−3 M _⊕ ), which material is concentrated at stellocentric distances less than 25 au. The dust material consists of amorphous carbon and SiC, with 84% of the dust being amorphous carbon. Dust particle radii range from 5 to 950 nm and follow a power law with an exponent of −3.5. Modeling the envelope allowed us to improve the accuracy of stellar luminosity estimations: 21,000 L _⊙ and 8300 L _⊙ at maximum and minimum brightness, respectively. The relation between the disk and the high water content in the envelope is also discussed. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astronomical Journal |
| spelling | doaj-art-9b0be5fca06146bfa19385caf9fc070a2025-02-12T07:22:17ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01169314010.3847/1538-3881/adaaf3Disk in the Circumstellar Envelope of Carbon Mira V CygniBoris S. Safonov0https://orcid.org/0000-0003-1713-3208Sergey G. Zheltoukhov1https://orcid.org/0000-0002-6321-0924Andrey M. Tatarnikov2https://orcid.org/0000-0002-4398-6258Ivan A. Strakhov3https://orcid.org/0000-0003-0647-6133Victor I. Shenavrin4https://orcid.org/0000-0002-2287-8151Sternberg Astronomical Institute, Lomonosov Moscow State University , Universitetskii prospekt, 13, Moscow, Russian Federation, 119992, Russia ; safonov@sai.msu.ruSternberg Astronomical Institute, Lomonosov Moscow State University , Universitetskii prospekt, 13, Moscow, Russian Federation, 119992, Russia ; safonov@sai.msu.ruSternberg Astronomical Institute, Lomonosov Moscow State University , Universitetskii prospekt, 13, Moscow, Russian Federation, 119992, Russia ; safonov@sai.msu.ruSternberg Astronomical Institute, Lomonosov Moscow State University , Universitetskii prospekt, 13, Moscow, Russian Federation, 119992, Russia ; safonov@sai.msu.ruSternberg Astronomical Institute, Lomonosov Moscow State University , Universitetskii prospekt, 13, Moscow, Russian Federation, 119992, Russia ; safonov@sai.msu.ruAsymptotic giant branch (AGB) stars are the primary source of dust and complex molecules in the interstellar medium. The determination of outflow parameters is often hindered by the unknown geometry of the circumstellar environment, creating a demand for high-angular resolution observations. We use our near-infrared spectra and photometry of the carbon AGB star V Cyg, along with literature data, to construct its spectral energy distribution over a wide range of wavelengths. The dust envelope responsible for the infrared excess was also resolved in scattered polarized light at angular scales of 50–80 mas using differential speckle polarimetry. We present an interpretation of the thermal and scattered radiation of the dust using models of a spherical dusty outflow ( M _dust = 5.3 × 10 ^−7 M _⊙ ) and an inclined equatorial density enhancement, either in the form of a disk ( M _dust = 7.6 × 10 ^−3 M _⊕ ) or a torus ( M _dust = 5.7 × 10 ^−3 M _⊕ ), which material is concentrated at stellocentric distances less than 25 au. The dust material consists of amorphous carbon and SiC, with 84% of the dust being amorphous carbon. Dust particle radii range from 5 to 950 nm and follow a power law with an exponent of −3.5. Modeling the envelope allowed us to improve the accuracy of stellar luminosity estimations: 21,000 L _⊙ and 8300 L _⊙ at maximum and minimum brightness, respectively. The relation between the disk and the high water content in the envelope is also discussed.https://doi.org/10.3847/1538-3881/adaaf3Circumstellar envelopesMira variable starsInfrared spectroscopySpeckle interferometry |
| spellingShingle | Boris S. Safonov Sergey G. Zheltoukhov Andrey M. Tatarnikov Ivan A. Strakhov Victor I. Shenavrin Disk in the Circumstellar Envelope of Carbon Mira V Cygni The Astronomical Journal Circumstellar envelopes Mira variable stars Infrared spectroscopy Speckle interferometry |
| title | Disk in the Circumstellar Envelope of Carbon Mira V Cygni |
| title_full | Disk in the Circumstellar Envelope of Carbon Mira V Cygni |
| title_fullStr | Disk in the Circumstellar Envelope of Carbon Mira V Cygni |
| title_full_unstemmed | Disk in the Circumstellar Envelope of Carbon Mira V Cygni |
| title_short | Disk in the Circumstellar Envelope of Carbon Mira V Cygni |
| title_sort | disk in the circumstellar envelope of carbon mira v cygni |
| topic | Circumstellar envelopes Mira variable stars Infrared spectroscopy Speckle interferometry |
| url | https://doi.org/10.3847/1538-3881/adaaf3 |
| work_keys_str_mv | AT borisssafonov diskinthecircumstellarenvelopeofcarbonmiravcygni AT sergeygzheltoukhov diskinthecircumstellarenvelopeofcarbonmiravcygni AT andreymtatarnikov diskinthecircumstellarenvelopeofcarbonmiravcygni AT ivanastrakhov diskinthecircumstellarenvelopeofcarbonmiravcygni AT victorishenavrin diskinthecircumstellarenvelopeofcarbonmiravcygni |