HR 4049: A Spectroscopic Analysis of a Post-AGB Object
A new spectroscopic study of HR 4049, a post-AGB star in a binary system, based on échelle spectra taken between 2019 and 2025 with the 0.81 m telescope of the Three College Observatory (North Carolina, USA) at a resolution of R ≈ 12,000 is reported. A cross-correlation analysis of 73 spectra of a s...
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2025-03-01
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| author | Shakhida T. Nurmakhametova Nadezhda L. Vaidman Anatoly S. Miroshnichenko Azamat A. Khokhlov Aldiyar T. Agishev Berik S. Yermekbayev Stephen Danford Alicia N. Aarnio |
| author_facet | Shakhida T. Nurmakhametova Nadezhda L. Vaidman Anatoly S. Miroshnichenko Azamat A. Khokhlov Aldiyar T. Agishev Berik S. Yermekbayev Stephen Danford Alicia N. Aarnio |
| author_sort | Shakhida T. Nurmakhametova |
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| description | A new spectroscopic study of HR 4049, a post-AGB star in a binary system, based on échelle spectra taken between 2019 and 2025 with the 0.81 m telescope of the Three College Observatory (North Carolina, USA) at a resolution of R ≈ 12,000 is reported. A cross-correlation analysis of 73 spectra of a single C <span style="font-variant: small-caps;">i</span> multiplet in the 4760–4780 Å range yielded the following orbital parameters: the orbital period <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mo>=</mo><mn>428.474</mn><mo>±</mo><mn>0.002</mn></mrow></semantics></math></inline-formula> days, eccentricity <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>e</mi><mo>=</mo><mn>0.29</mn><mo>±</mo><mn>0.01</mn></mrow></semantics></math></inline-formula>, argument of periastron <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ω</mi><mo>=</mo><msup><mn>242.3</mn><mo>∘</mo></msup><mo>±</mo><msup><mn>0.3</mn><mo>∘</mo></msup></mrow></semantics></math></inline-formula>, epoch of periastron <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>T</mi><mn>0</mn></msub><mo>=</mo><mrow><mn>2,458,383.2</mn></mrow><mo>±</mo><mn>0.6</mn></mrow></semantics></math></inline-formula>, heliocentric systemic radial velocity <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>γ</mi><mo>=</mo><mo>−</mo><mn>30.12</mn><mo>±</mo><mn>0.09</mn></mrow></semantics></math></inline-formula> km s<sup>−1</sup>, and semi-amplitude of the radial velocity curve <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>K</mi><mn>1</mn></msub><mo>=</mo><mn>15.52</mn><mo>±</mo><mn>0.13</mn></mrow></semantics></math></inline-formula> km s<sup>−1</sup>. Phase-dependent variations of the H<i>α</i> line profile indicate dynamic processes in the circumstellar environment. The luminosity of HR 4049 was refined using the Gaia EDR3 parallax (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.71</mn><mo>±</mo><mn>0.10</mn></mrow></semantics></math></inline-formula> mas), corresponding to a distance of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1397</mn><mo>±</mo><mn>170</mn></mrow></semantics></math></inline-formula> pc, and the average visual magnitude in the brightest state (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>m</mi><mi>V</mi></msub><mo>=</mo><mn>5.35</mn></mrow></semantics></math></inline-formula> mag). The derived luminosity, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo form="prefix">log</mo><mo>(</mo><mi>L</mi><mo>/</mo><msub><mi>L</mi><mo>⊙</mo></msub><mo>)</mo><mo>=</mo><mn>4.22</mn><mo>±</mo><mn>0.12</mn></mrow></semantics></math></inline-formula>, suggests an initial mass of 3.0–4.0 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>M</mi><mo>⊙</mo></msub></semantics></math></inline-formula>. Analysis of the mass function and most probable orbital inclinations (60°–75°) leads to current masses of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∼</mo><mn>0.75</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> for the primary and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.70</mn></mrow></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.82</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> for the secondary component. The results confirm the system’s long-term orbital stability and provide further insights for future research into the nature of post-AGB binaries. |
| format | Article |
| id | doaj-art-ad2fdbe3eb3f4f488951381e3c74b067 |
| institution | OA Journals |
| issn | 2075-4434 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Galaxies |
| spelling | doaj-art-ad2fdbe3eb3f4f488951381e3c74b0672025-08-20T02:18:05ZengMDPI AGGalaxies2075-44342025-03-011322610.3390/galaxies13020026HR 4049: A Spectroscopic Analysis of a Post-AGB ObjectShakhida T. Nurmakhametova0Nadezhda L. Vaidman1Anatoly S. Miroshnichenko2Azamat A. Khokhlov3Aldiyar T. Agishev4Berik S. Yermekbayev5Stephen Danford6Alicia N. Aarnio7Faculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty 050040, KazakhstanFaculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty 050040, KazakhstanFesenkov Astrophysical Institute, Observatory, 23, Almaty 050020, KazakhstanFaculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty 050040, KazakhstanFaculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty 050040, KazakhstanFaculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty 050040, KazakhstanDepartment of Physics and Astronomy, University of North Carolina—Greensboro, Greensboro, NC 27402, USADepartment of Physics and Astronomy, University of North Carolina—Greensboro, Greensboro, NC 27402, USAA new spectroscopic study of HR 4049, a post-AGB star in a binary system, based on échelle spectra taken between 2019 and 2025 with the 0.81 m telescope of the Three College Observatory (North Carolina, USA) at a resolution of R ≈ 12,000 is reported. A cross-correlation analysis of 73 spectra of a single C <span style="font-variant: small-caps;">i</span> multiplet in the 4760–4780 Å range yielded the following orbital parameters: the orbital period <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mo>=</mo><mn>428.474</mn><mo>±</mo><mn>0.002</mn></mrow></semantics></math></inline-formula> days, eccentricity <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>e</mi><mo>=</mo><mn>0.29</mn><mo>±</mo><mn>0.01</mn></mrow></semantics></math></inline-formula>, argument of periastron <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ω</mi><mo>=</mo><msup><mn>242.3</mn><mo>∘</mo></msup><mo>±</mo><msup><mn>0.3</mn><mo>∘</mo></msup></mrow></semantics></math></inline-formula>, epoch of periastron <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>T</mi><mn>0</mn></msub><mo>=</mo><mrow><mn>2,458,383.2</mn></mrow><mo>±</mo><mn>0.6</mn></mrow></semantics></math></inline-formula>, heliocentric systemic radial velocity <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>γ</mi><mo>=</mo><mo>−</mo><mn>30.12</mn><mo>±</mo><mn>0.09</mn></mrow></semantics></math></inline-formula> km s<sup>−1</sup>, and semi-amplitude of the radial velocity curve <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>K</mi><mn>1</mn></msub><mo>=</mo><mn>15.52</mn><mo>±</mo><mn>0.13</mn></mrow></semantics></math></inline-formula> km s<sup>−1</sup>. Phase-dependent variations of the H<i>α</i> line profile indicate dynamic processes in the circumstellar environment. The luminosity of HR 4049 was refined using the Gaia EDR3 parallax (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.71</mn><mo>±</mo><mn>0.10</mn></mrow></semantics></math></inline-formula> mas), corresponding to a distance of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1397</mn><mo>±</mo><mn>170</mn></mrow></semantics></math></inline-formula> pc, and the average visual magnitude in the brightest state (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>m</mi><mi>V</mi></msub><mo>=</mo><mn>5.35</mn></mrow></semantics></math></inline-formula> mag). The derived luminosity, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo form="prefix">log</mo><mo>(</mo><mi>L</mi><mo>/</mo><msub><mi>L</mi><mo>⊙</mo></msub><mo>)</mo><mo>=</mo><mn>4.22</mn><mo>±</mo><mn>0.12</mn></mrow></semantics></math></inline-formula>, suggests an initial mass of 3.0–4.0 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>M</mi><mo>⊙</mo></msub></semantics></math></inline-formula>. Analysis of the mass function and most probable orbital inclinations (60°–75°) leads to current masses of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∼</mo><mn>0.75</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> for the primary and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.70</mn></mrow></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.82</mn><mspace width="3.33333pt"></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> for the secondary component. The results confirm the system’s long-term orbital stability and provide further insights for future research into the nature of post-AGB binaries.https://www.mdpi.com/2075-4434/13/2/26spectroscopybinary starsemission-line starspost-AGB starscircumstellar matter |
| spellingShingle | Shakhida T. Nurmakhametova Nadezhda L. Vaidman Anatoly S. Miroshnichenko Azamat A. Khokhlov Aldiyar T. Agishev Berik S. Yermekbayev Stephen Danford Alicia N. Aarnio HR 4049: A Spectroscopic Analysis of a Post-AGB Object Galaxies spectroscopy binary stars emission-line stars post-AGB stars circumstellar matter |
| title | HR 4049: A Spectroscopic Analysis of a Post-AGB Object |
| title_full | HR 4049: A Spectroscopic Analysis of a Post-AGB Object |
| title_fullStr | HR 4049: A Spectroscopic Analysis of a Post-AGB Object |
| title_full_unstemmed | HR 4049: A Spectroscopic Analysis of a Post-AGB Object |
| title_short | HR 4049: A Spectroscopic Analysis of a Post-AGB Object |
| title_sort | hr 4049 a spectroscopic analysis of a post agb object |
| topic | spectroscopy binary stars emission-line stars post-AGB stars circumstellar matter |
| url | https://www.mdpi.com/2075-4434/13/2/26 |
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