HYBRID NOVA ASASSN-17HX (SCT 2017)
Heading:
| 1Alisheva, KI, 1Mikailov, Kh.M 1Department of Astrophysics, Baku State University, Baku, Azerbaijan |
| Space Sci. & Technol. 2026, 32 ;(4):64-82 |
| https://doi.org/10.15407/knit2026.04.064 |
| Publication Language: English |
Abstract: ASASSN-17hx is a remarkable hybrid nova that exhibited repeated rebrightenings accompanied by substantial spectral changes
during its post-outburst evolution. In this study, we investigate its spectroscopic evolution using optical spectra obtained at the Shamakhy Astrophysical Observatory (ShAO) with the Shamakhy Fiber Echelle Spectrograph at a spectral resolution of (R = 28,000), together with spectra from the Astronomical Ring for Access to Spectroscopy (ARAS, R = 9,000...1,000) and the European Southern Observatory (ESO, R = 110,000). Th e observations analysed in this study cover the pre-maximum stage, the principal maximum, and two subsequent rebrightening episodes. Th e temporal behaviour of the Balmer, Fe II, He I, Na I D, Ca II H and K, and diff use interstellar band features was examined through measurements of line profi les, equivalent widths, and radial velocities. A detailed identifi cation of more than 250 spectral lines was carried out using the ShAO and high-resolution ESO spectra. Th e Balmer and Fe II lines exhibit pronounced multicomponent absorption structures whose radial velocities evolve throughout the rebrightening phase, indicating the presence of several expanding shells with diff erent kinematic properties. Th e He I 5876 and Na I D absorption features also show systematic variations that closely follow the photometric evolution of the nova. Th e high-resolution ESO spectra reveal seven distinct interstellar absorption components in the Na I D and Ca II H and K lines, providing constraints on the interstellar matter along the line of sight. Th e diff use interstellar band profi les measured in the ShAO and ESO spectra are in good agreement despite the substantial diff erence in spectral resolution. Th e absolute visual magnitude of the nova was estimated as MV = –7.56m, and its distance as approximately 4.5 kpc. Th e observed spectral evolution confi rms the hybrid nature of ASASSN-17hx and indicates that repeated mass-ejection episodes played an important role in shaping the complex velocity structure of the ejecta during the rebrightening stage. Th ese results provide new observational constraints on the physical conditions and kinematics of hybrid novae. |
| Keywords: cataclysmic variables – stars: individual: ASASSN-17hx – line: profi les – techniques: spectroscopic – ISM: lines and bands, novae |
References:
Alisheva K. I., Mikailov Kh. M., Rustamov B. N., Alili A. H. (2024). Investigation of Nova Per 2020 (V1112 Per). Space Science
and Technology, 30(6), 59—66. https://doi.org/10.15407/knit2024.06.059
Berardi P., Tomasella L., Siviero A., Munari U., Ochner P., Valisa P., Castellani F., Dallaporta S., Moretti S., Cetrulo G., Nascimbeni
V. (2017). Continuing spectroscopic monitoring of Nova Sct 2017 = ASASSN-17hx. Th e Astronomer’s Telegram, No. 10558.
Chochol D., Shugarov S., Hambálek Ľ., Guarro J., Krushevska V. (2019). Optical photometry and spectroscopy of V612 Sct:
slow classical nova with rebrightenings. Contrib. Astron. Observatory Skalnaté Pleso, 49(2), 159—170.
Chomiuk L., Linford J. D., Yang J., O’Brien T. J., Paragi Z., Mioduszewski A. J., Ribeiro V. A. R. M., Beswick R., Nelson T.,
Sokoloski J. L., Rupen M. P., Mukai K., Weston J., Roy N., Eyres S. P. S., Bode M. F., Baan W. A. (2014). Binary orbits as
the driver of γ-ray emission and mass ejection in classical novae. Nature, 514(7522), 339—342. https://doi.org/10.1038/
nature13773
Friedman S. D., York D. G., McCall B. J., Dahlstrom J., Welty D. E., Danks A. C., Hobbs L. M., Sonnentrucker P., Snow T. P.
(2011). Studies of the Diff use Interstellar Bands. V. Pairwise Correlations of Eight Strong DIBs and Neutral Hydrogen.
Astrophys. J., 727, 33. https://doi.org/10.1088/0004-637X/727/1/33
Krełowski J., Galazutdinov G., Godunova V., Bondar A. (2019). On the Relation between Interstellar Spectral Features and
Reddening. Acta Astronomica, 69(2), 159—175. https://doi.org/10.32023/0001-5237/69.2.4
Kurtenkov A. T., Tomov T., Pessev P. (2017). Spectroscopic classifi cation of Nova ASASSN-17hx (Nova Scuti 2017). Th e
Astronomer’s Telegram, No. 10527.
Mason E., Shore S. N., Kuin N. P. M., Page K. L., De Gennaro Aquino I., Starrfi eld S., Aydi E., Izzo L., Munari U. (2020).
Th e ambiguous transient ASASSN-17hx: a possible nova impostor. Astron. and Astrophys., 635, A115. https://doi.
org/10.1051/0004-6361/201937025
Mikailov Kh. M., Musaev F. A., Alekberov I. A., Rustamov B. N., Khalilov O. V. (2020). Shamakhy Fiber Echelle Spectrograph.
Kinematics and Physics of Celestial Bodies, 36(1), 22—36. https://doi.org/10.3103/S0884591320010043
Molaro P., Izzo L., Bonifacio P., Hernanz M., Selvelli P., Della Valle M. (2020). Search for 7Be in the outbursts of four recent
novae. Mon. Notic. Roy. Astron. Soc., 492(4), 4975—4985. https://doi.org/10.1093/mnras/stz3587
Munari U. (2014). On Some Aspects of Optical Observations of Novae. Astron. Soc. Pacif. Conf. Ser., 490, 183—192.
Munari U., Hambsch F.-J., Frigo A., Castellani F., La Mura G., Traven G., Ozbey Arabaci M., Saguner T. (2017). Photometry
and spectroscopy of Fe II nova ASASSN-17hx, fi nally passing through maximum. Th e Astronomer’s Telegram, No. 10572.
Munari U., Zwitter T. (1997). Equivalent width of Na I and K I lines and the reddening of novae. Astron. and Astrophys., 318,
269—274.
Özdönmez A., Ege E., Güver T., Ak T. (2018). A new catalogue of Galactic novae: Investigation of the MMRD relation and
spatial distribution. Mon. Notic. Roy. Astron. Soc., 476(3), 4162—4186. https://doi.org/10.1093/mnras/sty432
Pavana M., Anupama G. C., Selvakumar G., Kiran B. S. (2017). Optical spectroscopy of Nova ASASSN-17hx (Nova Scuti
2017). Th e Astronomer’s Telegram, No. 10613.
Stanek K. Z., Kochanek C. S., Chomiuk L., Strader J., Brown J. S., Holoien T. W.-S., Shields J. V., Th ompson T. A., Shappee B. J.,
Prieto J. L., Dong S. (2017). ASAS-SN Discovery of a Possible Galactic Nova ASASSN-17hx on the Rise. Th e Astronomer’s
Telegram, No. 10523.
Strope R. J., Schaefer B. E., Henden A. A. (2010). Catalog of 93 Nova Light Curves: Classifi cation and Properties. Astron. J.,
140(1), 34—62. https://doi.org/10.1088/0004-6256/140/1/34
Williams R. E. (1992). Th e Formation of Novae Spectra. Astron. J., 104(2), 725—733. https://doi.org/10.1086/116268
Williams R. E. (2012). Origin of the “He/N” and “Fe II” Spectral Classes of Novae. Astron. J., 144(4), 98. https://doi.
org/10.1088/0004-6256/144/4/98
Williams R. E., Phillips M. M., Hamuy M. (1994). Th e Tololo Nova Survey: Spectra of Recent Novae. Astrophys. J. Suppl. Ser.,
90, 297—316. https://doi.org/10.1086/191864
Williams S. C., Darnley M. J. (2017). Liverpool Telescope Spectroscopy of ASASSN-17hx. Th e Astronomer’s Telegram, No. 10542.
and Technology, 30(6), 59—66. https://doi.org/10.15407/knit2024.06.059
Berardi P., Tomasella L., Siviero A., Munari U., Ochner P., Valisa P., Castellani F., Dallaporta S., Moretti S., Cetrulo G., Nascimbeni
V. (2017). Continuing spectroscopic monitoring of Nova Sct 2017 = ASASSN-17hx. Th e Astronomer’s Telegram, No. 10558.
Chochol D., Shugarov S., Hambálek Ľ., Guarro J., Krushevska V. (2019). Optical photometry and spectroscopy of V612 Sct:
slow classical nova with rebrightenings. Contrib. Astron. Observatory Skalnaté Pleso, 49(2), 159—170.
Chomiuk L., Linford J. D., Yang J., O’Brien T. J., Paragi Z., Mioduszewski A. J., Ribeiro V. A. R. M., Beswick R., Nelson T.,
Sokoloski J. L., Rupen M. P., Mukai K., Weston J., Roy N., Eyres S. P. S., Bode M. F., Baan W. A. (2014). Binary orbits as
the driver of γ-ray emission and mass ejection in classical novae. Nature, 514(7522), 339—342. https://doi.org/10.1038/
nature13773
Friedman S. D., York D. G., McCall B. J., Dahlstrom J., Welty D. E., Danks A. C., Hobbs L. M., Sonnentrucker P., Snow T. P.
(2011). Studies of the Diff use Interstellar Bands. V. Pairwise Correlations of Eight Strong DIBs and Neutral Hydrogen.
Astrophys. J., 727, 33. https://doi.org/10.1088/0004-637X/727/1/33
Krełowski J., Galazutdinov G., Godunova V., Bondar A. (2019). On the Relation between Interstellar Spectral Features and
Reddening. Acta Astronomica, 69(2), 159—175. https://doi.org/10.32023/0001-5237/69.2.4
Kurtenkov A. T., Tomov T., Pessev P. (2017). Spectroscopic classifi cation of Nova ASASSN-17hx (Nova Scuti 2017). Th e
Astronomer’s Telegram, No. 10527.
Mason E., Shore S. N., Kuin N. P. M., Page K. L., De Gennaro Aquino I., Starrfi eld S., Aydi E., Izzo L., Munari U. (2020).
Th e ambiguous transient ASASSN-17hx: a possible nova impostor. Astron. and Astrophys., 635, A115. https://doi.
org/10.1051/0004-6361/201937025
Mikailov Kh. M., Musaev F. A., Alekberov I. A., Rustamov B. N., Khalilov O. V. (2020). Shamakhy Fiber Echelle Spectrograph.
Kinematics and Physics of Celestial Bodies, 36(1), 22—36. https://doi.org/10.3103/S0884591320010043
Molaro P., Izzo L., Bonifacio P., Hernanz M., Selvelli P., Della Valle M. (2020). Search for 7Be in the outbursts of four recent
novae. Mon. Notic. Roy. Astron. Soc., 492(4), 4975—4985. https://doi.org/10.1093/mnras/stz3587
Munari U. (2014). On Some Aspects of Optical Observations of Novae. Astron. Soc. Pacif. Conf. Ser., 490, 183—192.
Munari U., Hambsch F.-J., Frigo A., Castellani F., La Mura G., Traven G., Ozbey Arabaci M., Saguner T. (2017). Photometry
and spectroscopy of Fe II nova ASASSN-17hx, fi nally passing through maximum. Th e Astronomer’s Telegram, No. 10572.
Munari U., Zwitter T. (1997). Equivalent width of Na I and K I lines and the reddening of novae. Astron. and Astrophys., 318,
269—274.
Özdönmez A., Ege E., Güver T., Ak T. (2018). A new catalogue of Galactic novae: Investigation of the MMRD relation and
spatial distribution. Mon. Notic. Roy. Astron. Soc., 476(3), 4162—4186. https://doi.org/10.1093/mnras/sty432
Pavana M., Anupama G. C., Selvakumar G., Kiran B. S. (2017). Optical spectroscopy of Nova ASASSN-17hx (Nova Scuti
2017). Th e Astronomer’s Telegram, No. 10613.
Stanek K. Z., Kochanek C. S., Chomiuk L., Strader J., Brown J. S., Holoien T. W.-S., Shields J. V., Th ompson T. A., Shappee B. J.,
Prieto J. L., Dong S. (2017). ASAS-SN Discovery of a Possible Galactic Nova ASASSN-17hx on the Rise. Th e Astronomer’s
Telegram, No. 10523.
Strope R. J., Schaefer B. E., Henden A. A. (2010). Catalog of 93 Nova Light Curves: Classifi cation and Properties. Astron. J.,
140(1), 34—62. https://doi.org/10.1088/0004-6256/140/1/34
Williams R. E. (1992). Th e Formation of Novae Spectra. Astron. J., 104(2), 725—733. https://doi.org/10.1086/116268
Williams R. E. (2012). Origin of the “He/N” and “Fe II” Spectral Classes of Novae. Astron. J., 144(4), 98. https://doi.
org/10.1088/0004-6256/144/4/98
Williams R. E., Phillips M. M., Hamuy M. (1994). Th e Tololo Nova Survey: Spectra of Recent Novae. Astrophys. J. Suppl. Ser.,
90, 297—316. https://doi.org/10.1086/191864
Williams S. C., Darnley M. J. (2017). Liverpool Telescope Spectroscopy of ASASSN-17hx. Th e Astronomer’s Telegram, No. 10542.