| Name: | Atul Mohan |
| Affiliation: | NASA Goddard Space Flight Center |
| Conference ID : | ASI2024_512 |
| Title : | Properties of CME-related type-IV radio bursts and its discovery in an active non-solar type star |
| Authors : | Atul Mohan1,2, Surajit Mondal3, Natchimuthuk Gopalswamy2, Anshu Kumari2, Sachiko Akiyama1,2, Sindhuja Gunaseelan1,2, Sven Wedemeyer4,5 |
| Authors Affiliation: | 1Atul Mohan, Sachiko Akiyama, Sindhuja Gunaseelan Affiliation (The Catholic University of America, Washington, DC-2006, USA )
2Atul Mohan, Natchimuthuk Gopalswamy, Anshu Kumari, Sachiko Akiyama, Sindhuja Gunaseelan Affiliation (NASA Goddard Space Flight Center, Greenbelt, MD-20771, USA)
3Surajit Mondal Affiliation (Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102-1982, USA)
4Sven Wedemeyer Affiliation (Rosseland Centre for Solar Physics, University of Oslo, Blindern, N-0315 Oslo, Norway)
5Sven Wedemeyer Affiliation (Institute of Theoretical Astrophysics, University of Oslo, Blindern, N-0315 Oslo, Norway) |
| Mode of Presentation: | Oral |
| Abstract Category : | Sun, Solar System, Exoplanets, and Astrobiology |
| Abstract : | A Type-IV burst is generated by flare-accelerated electrons trapped either in the post-flare loops or in the moving magnetic structures associated with the underlying coronal mass ejection (CME). Type-IVs are largely associated with fast (>900 km/s) and wide (>60 deg) CMEs, particularly Halo CMEs, and hence are important tracers of space weather events (Gopalswamy 2011; Hillaris et al. 2016; Miteva et al. 2017). These bursts are therefore, a widely sought out signature of stellar CMEs/Superflares. However, type-IV bursts are relatively rare events especially in the Decameter-Hectometric (DH; <15 MHz) band which probe the interplanetary space. Additionally, since the DH band emission can be probed only from space, Wind/WAVES (since ~1995) and STEREO/SWAVES (since ~2006) are the only source of long term data. Type IV data from two complete solar cycles (23, 24) and the rising cycle 25 are available from these instruments, enabling statistical investigations. We report on our comprehensive catalog of DH type-IVs and discuss the characteristics of the radio bursts and associated CMEs. Type-IV emission has been reported to show directivity (Gopalswamy et al. 2016), which will be explored using multi-vantage point data from STEREO A, B and Wind. In the stellar context, we discuss the GMRT discovery of a metric-type-IV radio burst in AD Leo (M3.5V), a ~250 Myr old young fast rotating (period ~ 2.3 d) active star, which belongs to a very different population in the age-activity plane. The star is close to the internal core transition boundary (Mass~ 0.4 Msun), making the discovery particularly interesting. We will discuss the emission mechanism and the possible magnetic field structure in the stellar active region constrained by radio observations, and compare with the solar case. |
