Nova Lup 2025

[Francois Teyssier]

Bright nova in Lupus
RA 15:08:03.274 DE -40:08:29.58
discovered by ASASSN (
https://www.wis-tns.org/object/2025nlr
Identified as nova by Yusuke Tampo: https://www.astronomerstelegram.org/?read=17228

First spectra secured by Keith Shank in the database: https://aras-database.github.io/databas ... p2025.html

Comments by Steve Shore:

The spectra now are important -- at high resolution -- for understanding how the recombination wave Francois described passes through the density structures in the ejecta. The effect isn't just one of temperature as the fireball expands, it's also that the ejecta have a sort of pseudo-surface -- the comoving photosphere -- that effectively screens the outer parts of the ejecta from the hard radiation of the central source. There will also be shocked gas during this phase so there'll also be particle accelerationand gamma ray emission. It should produce a Fermi detection since it seems to be close enough (although it's still much father than V339 Del or V1369 Cen, for instance). But as dramatic as the changes seem here, the most important thing is to follow this at high resolution (as high as possile) with fluxed spectra. The nova is -- it seems -- rather "ordinary" which is precisely why it's important. If bright enough to have a high resolution sequence at the initial stages. The archives, including ARAS, are full of "first spectra" with little or no history (what more than 60 yerars ago Payne-Gaposchkin compained about in "Galactic Novae" as fragmentary data (which was a much longer list than those well followed). All of our understanding is based on these sequences and if we get this right we also understand a very broad range of transients. This is also what will come from the Rubin telescope (LSST) once it starts up (if it does in this funding atmosphere and anti-science era)..

= Long term monitoring !

[2SPOT]

Here's a spectrum of this Novae taken this morning from our 2SPOT setup in Chile and an eShel spectrograph (R=11000) 5 X 1200s.

The raw spectrum of one exposure



The full graph from 3900 to 7600 Å



Detail on H alpha line to mesure the ejecta velocity



And all Balmer line velocity comparison



The Nova is very bright and easy to take in medium resolution

[2SPOT]

Evolution of this nova in 7 days on H Alpha line



and an animation with our spectra

[Francois Teyssier]

Great monitoring.

[OI] 6300 is now obvious, classical evolution during the decline.

Spectra on: https://aras-database.github.io/databa ... p2025.html

Light curves from AAVSO observers:

NovaLup2025.png (23.99 KiB) Viewed 47 times

[Francois Teyssier]

Perhaps a rebrightning:

NovaLup20251.PNG (17.71 KiB) Viewed 30 times