Optical and soft X-ray light-curve analysis during the 2022 eruption of U Scorpii: Structural changes in the accretion disk-Reference-Cited by-同舟云学术

Optical and soft X-ray light-curve analysis during the 2022 eruption of U Scorpii: Structural changes in the accretion disk

Published:2024-03-07 Issue:2 Volume:76 Page:293-305
ISSN:0004-6264
Container-title:Publications of the Astronomical Society of Japan
language:en
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Author:

Muraoka Katsuki¹,Kojiguchi Naoto¹,Ito Junpei¹,Nogami Daisaku¹,Kato Taichi¹,Tampo Yusuke¹^ORCID,Taguchi Kenta¹^ORCID,Isogai Keisuke¹²³,Arranz Teofilo⁴,Blackwell John⁵,Blane David⁶⁷,Brincat Stephen M⁸,Coates Graeme⁹,Cooney Walter¹⁰,Dvorak Shawn¹¹,Galdies Charles¹²,Glomski Daniel¹³,Hambsch Franz-Josef¹⁴¹⁵¹⁶,Harris Barbara¹⁷,Hodge John¹⁸,Hernández-Verdejo Jose L¹⁹,Iozzi Marco²⁰,Itoh Hiroshi²¹,Kiyota Seiichiro²²,Lee Darrell²³,Larsson Magnus²⁴,Lahtinen Tapio²⁵,Myers Gordon²⁶,Monard Berto²⁷²⁸,Morales Aimar Mario²⁹,Moriyama Masayuki³⁰,Mizutani Masanori³¹,Nagai Kazuo³²,AlQaissieh Thabet³³,Gabuya Aldrin B³³,Odeh Mohammad³⁴,Perello Carlos³⁵,Pearce Andrew³⁶,Miguel Perales Juan³⁵³⁷,Quiles David³⁸,Romanov Filipp D³⁹⁴⁰⁴¹⁴²⁴³,Lane David J⁴⁰⁴¹⁴²,Richmond Michael⁴⁴,Ruocco Nello⁴⁵,Sano Yasuo⁴⁶⁴⁷⁴⁸,Spearman Mark⁴⁹⁵⁰,Schmidt Richard⁵¹,Vanmunster Tonny¹⁶⁵²⁵³,Dubovsky Pavol A⁵⁴,Wagner Richard⁵⁵⁵⁶,Wollenhaupt Guido⁵⁷⁵⁸,Lorenz Joachim⁵⁸,Lehmann Gerhard⁵⁸,Salewski Andrea⁵⁸,Williamson Guy⁵⁹

Affiliation:

1. Department of Astronomy, Graduate School of Science, Kyoto University , Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8502 , Japan

2. Okayama Observatory, Kyoto University , 3037-5 Honjo, Kamogata-cho, Asakuchi-shi, Okayama 719-0232 , Japan

3. Department of Multi-Disciplinary Sciences, Graduate School of Arts and Sciences, The University of Tokyo , 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 , Japan

4. Observatorio Astronómico “Las Pegueras” , Navas De Oro, Segovia 40470 , Spain

5. Phillips Exeter Academy , 20 Main Street, Exeter, NH 03833 , USA

6. American Association of Variable Star Observers (AAVSO) , 55 Dale Gardens, 18 Balder Road, Douglasdale, Sandton 2191 , South Africa

7. Astronomical Society of Southern Africa , Variable Star Section (ASSA)

8. Flarestar Observatory , San Gwann SGN 3160, Malta

9. British Astronomical Association, Variable Star Section , Standlake, Oxfordshire OX29 , UK

10. Madrona Peak Observatory , 4635 Shadow Grass Dr., Katy, TX 77493 , USA

11. American Association of Variable Star Observers (AAVSO) , Rolling Hills Observatory, Clermont, FL 34711 , USA

12. Institute of Earth Systems, University of Malta , Msida, MSD 2080 , Malta

13. American Association of Variable Star Observers (AAVSO) , Midland, MI , USA

14. Groupe Européen d’Observations Stellaires (GEOS) , 23 Parc de Levesville, 28300 Bailleau l’Evêque , France

15. Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne (BAV) , Munsterdamm 90, 12169 Berlin , Germany

16. Vereniging voor Sterrenkunde (VVS) , Oostmeers 122 C, 8000 Brugge , Belgium

17. American Association of Variable Star Observers (AAVSO) , New Smyrna Beach, FL , USA

18. Bethune Observers Group , Post Office Box 25553 Columbia, SC 29224 , USA

19. Universidad Complutense de Madrid, Avda. de Séneca, 2, Ciudad Universitaria , Madrid 28040 , Spain

20. American Association of Variable Star Observers (AAVSO) , Capraia e Limite, Firenze 50050 , Italy

21. Variable Star Observers League in Japan (VSOLJ) , 1001-105 Nishiterakata, Hachioji-shi, Tokyo 192-0153 , Japan

22. Variable Star Observers League in Japan (VSOLJ) , 7-1 Kitahatsutomi, Kamagaya-shi, Chiba 273-0126 , Japan

23. American Association of Variable Star Observers (AAVSO) , 2405 Steele Ranch Ct., Friendswood, TX 77546 , USA

24. Svensk Amator Astronomisk Forening, variabelsektionen (SAAF) , Sweden

25. URSA Astronomical Association, Variable Star Section (URSA) , Finland

26. American Association of Variable Star Observers (AAVSO) , Hillsborough, CA 94010 , USA

27. Bronberg Observatory, Center for Backyard Astrophysics Pretoria , PO Box 11426, Tiegerpoort 0056 , South Africa

28. Kleinkaroo Observatory, Center for Backyard Astrophysics Kleinkaroo , Sint Helena 1B, PO Box 281, Calitzdorp 6660 , South Africa

29. Observatorio de Sencelles, 07140 Sencelles, Balearic Islands , Spain

30. Variable Star Observers League in Japan (VSOLJ) , 290-383, Ogata-cho, Sasebo-shi, Nagasaki 858-0926 , Japan

31. Variable Star Observers League in Japan (VSOLJ) , Okayama , Japan

32. Variable Star Observers League in Japan (VSOLJ) , 5-9-3 B-305 Honson, Chigasaki-shi, Kanagawa 253-0042 , Japan

33. Al Sadeem Astronomy , Al Wathba South, Abu Dhabi , UAE

34. Al Khatim Observatory, International Astronomical Center , Abu Dhabi , UAE

35. Agrupació Astronòmica de Sabadell , Carrer Prat de la Riba, 116, Sabadell, Barcelona 08206 , Spain

36. Perth Observatory , 337 Walnut Rd, Bickley, WA 6076 , Australia

37. AstroMallorca, Asociación Astronómica de Mallorca , Spain

38. American Association of Variable Star Observers (AAVSO) , Calle San Vicente 18, 02660 Caudete , Spain

39. Pobedy Street , House 7, Flat 60, Yuzhno-Morskoy, Nakhodka, Primorsky Krai 692954 , Russia

40. American Association of Variable Star Observers (AAVSO) , 185 Alewife Brook Parkway, Suite 410, Cambridge, MA 02138 , USA

41. Burke-Gaffney Observatory, Saint Mary’s University , 923 Robie Street, Halifax, NS B3H3C3 , Canada

42. Abbey Ridge Observatory , 45 Abbey Rd, Stillwater Lake, NS B3Z1R1 , Canada

43. iTelescope.Net Observatory New Mexico Skies at Mayhill , NM 88339 , USA

44. School of Physics and Astronomy, Rochester Institute of Technology , Rochester, NY 14623 , USA

45. Observatorio Astronómico ”Nastro Verde” , Sorrento, Naples 80067 , Italy

46. Variable Star Observers League in Japan (VSOLJ) , Nishi juni-jou minami 3-1-5, Nayoro-shi, Hokkaido 080-0020 , Japan

47. Observation and Data Center for Cosmosciences, Faculty of Science, Hokkaido University , Kita-ku, Sapporo-shi, Hokkaido 060-0810 , Japan

48. Nayoro Observatory , 157-1 Nisshin, Nayoro-shi, Hokkaido 096-0066 , Japan

49. American Association of Variable Star Observers (AAVSO) , PO Box 274, Wheelock, TX 77882 , USA

50. Factory Physics, Inc. , Houston, TX 77019 , USA

51. Burleith Observatory , 1810 35th St NW, Washington, DC 20007 , USA

52. Center for Backyard Astrophysics Belgium , Walhostraat 1A, B-3401 Landen , Belgium

53. Center for Backyard Astrophyics Extremadura , e-EyE Astronomical Complex, 06340 Fregenal de la Sierra , Spain

54. Vihorlat Observatory , Mierova 4, 06601 Humenne , Slovakia

55. American Association of Variable Star Observers (AAVSO) , 126 Powell Bay Road, Elgin, ON K0G 1E0 , Canada

56. Royal Astronomical Society of Canada (RASC) , 203-489 College St., Toronto, ON M6G 1A5 , Canada

57. Bundesdeutsche Arbeitsgemeinschaft fur Veranderliche Sterne e.V. (BAV) , Oberwiesenthal , Germany

58. Drebach-South Observatory , Tivoli Southern Sky Guest Farm, Windhoek, Khomas 11854 , Namibia

59. American Association of Variable Star Observers (AAVSO) , Glasgow , UK

Abstract

Abstract We present our optical photometric observations of the 2022 eruption of the recurrent nova U Scorpii (U Sco) using 49152 data points over 70 d following the optical peak. We have also analyzed its soft X-ray (0.3–1 keV) light curve by the Neil Gehrels Swift Observatory. During the 2022 eruption, the optical plateau stage started 13.8–15.0 d and ended 23.8–25.0 d after the optical peak. The soft X-ray stage started 14.6–15.3 d and ended 38.7–39.5 d after the optical peak. Both stages started later and had shorter durations, and the soft X-ray light curve peaked earlier and was less luminous compared to those during the U Sco 2010 eruption. These points suggest that there were differences in the envelope mass between the different cycles of the nova eruption. Furthermore, we have analyzed the optical eclipses during the 2022 eruption. The primary eclipse was first observed 10.4–11.6 d after the optical peak, earlier than the beginning of the optical plateau stage. This sequence of events can be explained by the receding ejecta photosphere associated with the expanding nova ejecta. We have determined the ingress and egress phases of the primary eclipses and estimated the outer radius of the optical light source centered at the white dwarf (WD). During the optical plateau stage, the source radius remained ∼1.2 times larger than the Roche volume radius of the primary WD, being close to the L1 point. When the optical plateau stage ended, the source radius drastically shrank to the tidal truncation radius within a few orbital periods. This previously unresolved phenomenon can be interpreted as a structural change in U Sco where the temporarily expanded accretion disk due to the nova wind returned to a steady state.

Funder

Japan Society for the Promotion of Science

Slovak Research and Development Agency

National Science Foundation

Deutsches Elektronen-Synchrotron

Gordon and Betty Moore Foundation

Ohio State University

Mt. Cuba Astronomical Foundation

Center for Cosmology and Astroparticle Physics, Ohio State University

Chinese Academy of Sciences South America Center for Astronomy

Villum Foundation

NASA