Stellar Variability toward the Galactic Open Cluster NGC 7209
We present the analysis of stellar variability in an open cluster NGC 7209 using optical V -band CCD photometric observations. Out of 4499 stars in our study, we detected 284 candidate variables, including one identified previously. Using the machine learning algorithm HDBSCAN technique and Gaia DR3...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc696 |
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| author | Dorothy M. Mwanzia Sneh Lata W. P. Chen Soumen Mondal Geoffrey Okeng’o John Buers Samrat Ghosh Athul Dileep Arjav Jain Alisher S. Hojaev Santosh Joshi |
| author_facet | Dorothy M. Mwanzia Sneh Lata W. P. Chen Soumen Mondal Geoffrey Okeng’o John Buers Samrat Ghosh Athul Dileep Arjav Jain Alisher S. Hojaev Santosh Joshi |
| author_sort | Dorothy M. Mwanzia |
| collection | DOAJ |
| description | We present the analysis of stellar variability in an open cluster NGC 7209 using optical V -band CCD photometric observations. Out of 4499 stars in our study, we detected 284 candidate variables, including one identified previously. Using the machine learning algorithm HDBSCAN technique and Gaia DR3 data, we identified 246 cluster members with membership probability greater than 60%, among which 17 were identified in our study as variable stars. Based on isochrone fitting, we approximated the log(age) of the cluster to be 8.8 ± 0.2. We provide the first time-series V -band photometric study of 14 newly detected variable cluster members, detecting three potential δ Scuti, three γ Doradus, and four rotationally modulated variables, along with four possible eclipsing binaries. We detected an optical flare on 2022 November 30, from the star ID 1329 (R.A.: 331.50897; decl.: 46.44859), with an estimated emitted energy of 5.37 × 10 ^30 erg, which is below the typical energy range of a superflare; an error of a few tens of percent is attributed to the calculation of energy. |
| format | Article |
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| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-569dc4b231c04094ba842e9d39cf4fc12025-08-20T01:51:23ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198512610.3847/1538-4357/adc696Stellar Variability toward the Galactic Open Cluster NGC 7209Dorothy M. Mwanzia0Sneh Lata1https://orcid.org/0000-0001-9367-1580W. P. Chen2https://orcid.org/0000-0003-0262-272XSoumen Mondal3Geoffrey Okeng’o4John Buers5Samrat Ghosh6https://orcid.org/0000-0003-3354-850XAthul Dileep7Arjav Jain8Alisher S. Hojaev9Santosh Joshi10https://orcid.org/0009-0007-1545-854XUniversity of Nairobi , Faculty of Science and Technology, Department of Physics, P.O. Box 30197-00100, Nairobi, Kenya; S. N. Bose National Center for Basic Sciences , Salt Lake, Kolkata 700106, IndiaAryabhatta Research Institute of Observational Sciences , Manora Peak, Nainital 263001, Uttarakhand, IndiaGraduate Institute of Astronomy, National Central University , 300 Zhongda Road, Zhongli 32001 Taoyuan, Taiwan; Department of Physics, National Central University , 300 Zhongda Road, Zhongli 32001 Taoyuan, TaiwanS. N. Bose National Center for Basic Sciences , Salt Lake, Kolkata 700106, IndiaUniversity of Nairobi , Faculty of Science and Technology, Department of Physics, P.O. Box 30197-00100, Nairobi, KenyaUniversity of Nairobi , Faculty of Science and Technology, Department of Physics, P.O. Box 30197-00100, Nairobi, KenyaAryabhatta Research Institute of Observational Sciences , Manora Peak, Nainital 263001, Uttarakhand, IndiaAryabhatta Research Institute of Observational Sciences , Manora Peak, Nainital 263001, Uttarakhand, IndiaAryabhatta Research Institute of Observational Sciences , Manora Peak, Nainital 263001, Uttarakhand, IndiaUlugh Beg Astronomical Institute , Uzbekistan Academy of Sciences, Tashkent, UzbekistanAryabhatta Research Institute of Observational Sciences , Manora Peak, Nainital 263001, Uttarakhand, IndiaWe present the analysis of stellar variability in an open cluster NGC 7209 using optical V -band CCD photometric observations. Out of 4499 stars in our study, we detected 284 candidate variables, including one identified previously. Using the machine learning algorithm HDBSCAN technique and Gaia DR3 data, we identified 246 cluster members with membership probability greater than 60%, among which 17 were identified in our study as variable stars. Based on isochrone fitting, we approximated the log(age) of the cluster to be 8.8 ± 0.2. We provide the first time-series V -band photometric study of 14 newly detected variable cluster members, detecting three potential δ Scuti, three γ Doradus, and four rotationally modulated variables, along with four possible eclipsing binaries. We detected an optical flare on 2022 November 30, from the star ID 1329 (R.A.: 331.50897; decl.: 46.44859), with an estimated emitted energy of 5.37 × 10 ^30 erg, which is below the typical energy range of a superflare; an error of a few tens of percent is attributed to the calculation of energy.https://doi.org/10.3847/1538-4357/adc696Open star clustersVariable starsDelta Scuti variable starsGamma Doradus variable starsFlare starsAstrometric binary stars |
| spellingShingle | Dorothy M. Mwanzia Sneh Lata W. P. Chen Soumen Mondal Geoffrey Okeng’o John Buers Samrat Ghosh Athul Dileep Arjav Jain Alisher S. Hojaev Santosh Joshi Stellar Variability toward the Galactic Open Cluster NGC 7209 The Astrophysical Journal Open star clusters Variable stars Delta Scuti variable stars Gamma Doradus variable stars Flare stars Astrometric binary stars |
| title | Stellar Variability toward the Galactic Open Cluster NGC 7209 |
| title_full | Stellar Variability toward the Galactic Open Cluster NGC 7209 |
| title_fullStr | Stellar Variability toward the Galactic Open Cluster NGC 7209 |
| title_full_unstemmed | Stellar Variability toward the Galactic Open Cluster NGC 7209 |
| title_short | Stellar Variability toward the Galactic Open Cluster NGC 7209 |
| title_sort | stellar variability toward the galactic open cluster ngc 7209 |
| topic | Open star clusters Variable stars Delta Scuti variable stars Gamma Doradus variable stars Flare stars Astrometric binary stars |
| url | https://doi.org/10.3847/1538-4357/adc696 |
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