Time series photometry of the nova V462 Lup simultaneously with NuSTAR X-ray observations
Abstract:
Dr. Kirill Sokolovsky (Sternberg Astronomical Institute) writes: Filtered or clear-band time series photometry of Nova V462 Lup is requested during and around the time of NuSTAR X-ray observations of this nova scheduled to start on 2025-06-30 00:55 and end on 2025-07-01 00:25 UTC.
Justification:
Detection of correlated brightness variations in optical and X-ray bands may provide crucial insights into shock formation and energy transport within nova ejecta. Shocks in novae manifest themselves in multiple ways: they heat plasma, making it emit X-rays and high-ionization coronal lines seen in optical spectra, and they accelerate particles to high energies, producing non-thermal gamma-ray and radio emission. Some of the energy transported by shocks may contribute to optical emission of novae, as suggested by a series of simultaneous gamma-ray and optical flares observed in nova V906 Car (2018). However, the relation between shocks responsible for gamma-ray, X-ray, and synchrotron radio emission is unclear. The relative brightness of shock-powered emission in these bands indicates that it is either one shock with properties that lack satisfactory theoretical explanation or a system of multiple independent shocks. It is unclear why multiple shocks form and where they are located within nova ejecta. Observation of a flare simultaneously in X-ray and optical bands would be a clear indication that the X-ray-emitting shock also contributes to nova optical light. So far, simultaneous NuSTAR and optical observations were obtained for two novae, V1674 Her (2021) and V1716 Sco (2023); in both cases the X-ray and optical variations appeared to be completely independent of each other. We propose to attempt this search for the third time with the new bright nova V462 Lup. Spectroscopy during the NuSTAR observation would also be useful to estimate the nova shell expansion velocity at this specific epoch.
Requested Data Types:
Photometry
Targets
| Name | Magnitude | Variability Type | Photometry Notes | Spectroscopy Notes |
|---|---|---|---|---|
| N Lup 2025 | 6.80 | N |
Cadence: Custom Precision: 100 |
Not Requested |
Spectroscopy Lines:
H-beta (4861.0 Å), H-alpha (6563.0 Å)
Photometry Filters:
V (Johnson)
Comparison Stars:
Finder charts with comparison stars may be created using the AAVSO Variable Star Plotter (VSP, https://apps.aavso.org/vsp/). An 'AB' scale chart shows comp stars as bright as 5th mag, with one 2nd mag star.
Co-Authorship
Observers are eligible for co-authorship.
Additional Observer Input:
Hours-long time series in V band is most desirable. The use of V filter minimizes observer-to-observer offsets and differential extinction effects when observing down to a low elevation. Novae typically have strong H_alpha emission which is mostly avoided by V filter simplifying calibration. If V filter is not available, time series observations in other filters as well as unfiltered observations would be useful too.
Additional Submission Location:
Not provided
Notes:
Brightness variations in classical novae that happen on hours to days timescales are generally not well documented and their origin is not well understood. Periodic variations may be hiding among irregular changes and individual (possibly shock-produced) flares. Coordinated multi-site observations are needed to reliably trace these variations.