AAVSO: American Association of Variable Star Observers

Proposal #120

Proposer (31841) Frederick Walter (frederick.walter@stonybrook.edu) obscode: WFM
Assigned To(3663) Dirk Terrell
Date SubmittedOct. 23, 2019

I propose to monitor four still-bright recent galactic novae in BVRI.
A small fraction of the novae do more than just fade away - it is these that provide clues to the physics of the novae and their shells.

Our long-term monitoring program began in 2003, and continued until the retirement of the Andicam dual-channel photometer on the SMARTS/CTIO 1.3m in
July 2019. Since then we have relied on AAVSO alerts for the more critical targets, and have proposed to LCO for time to continue to follow the fainter
(V>15) targets. By off-loading this more-or-less routine monitoring to AAVSOnet, we can free up the southern observers to tackle more timely targets. These observations
will support our on-going high dispersion spectroscopic studies.

These targets are located in the vicinity of the Galactic center, and become observable again between October 2019 and February 2020.

Our targets are:
- V1280 Sco. This bright nova is stalled at V~11, some 6-7 mag brighter than its pre-outburst brightness. It is varying apparently randomly with 11.5<V<10.3;
there are no color variations. We continue to obtain high dispersion spectra; the line spectrum is unlike any other nova I have observed. When
bright (V<10.5) the spectrum is dominated by low excitation lines of Fe II; when faint (V>11) a hot spectrum (He II, N III, C IV) with forbidden lines
([O III], [Fe VII]) appears. We seek to quantify the repeatability of the two excitation states and develop a model. At some point the system must fade
some 6-7 mag back to its pre-outburst state.
The target flickers by a few tenths of a mag each night.
We propose to monitoring this target in BVRI on a 5 day cadence from early February through mid-October 2020, with nightly monitoring in March and April

- V5856 Sgr (ASASSN-16ma) is a slow, broad-lined nova. It was discoved as a Fermi gamma-ray source. The nova was picked up optically at an age of about
6 months at V~11.5. The OGLE pre-outburst I magnitude was >22, so it has brightened by over 11 mag. the nova faded to V~12.5 during the 2018 observing
season, but during 2019 varied between V=12.0 and 12.5. It has not been well-observed by the AAVSO.
We propose to monitor this slow nova about every fifth night through the 2020 observing season. Either it will start to fade, or it will continue its
peculiar oscillatory behavior.

- V906 Car and FM Cir and slow novae discovered before peak in 2018. The current V magnitudes were 10.5 and 11.2 at the end of the 2019 observing
season, and should be at 10.5 and 11.7, respectively, in 2020. We do not expect any fireworks, but the changing colors complement the spectra by
inform us about the strength of the forbidden line emission ([O III], [N II]). These stars are being observed infrequently by AAVSO observers.
We propose bi-weekly monitoring of these two targets.

Magnitudes will be reported to the AAVSO and added to the Stony Brook/SMARTS Nova Atlas (http://www.astro.sunysb.edu/fwalter/SMARTS/NovaAtlas/atlas.html).
Our current photometry can be accessed through the atlas.
We have our own calibrations for these fields, so standard star fields are unnecessary.

Observing details:
Each target should be observed in 4 filters: BVRI at each visit.

Target Cadences
V1280 Sco 5 nights, except nightly March-April
V5856 Sgr 5 nights
V906 Car 14 nights
FM Cir 14 nights

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
V1280 Sco 16.961449 -32.34340 11.5–10.3 BSM_S July 23, 2020 No
V5856 Sgr 18.347801 -28.37040 12.5–12.0 BSM_S July 23, 2020 No
V906 Car 10.604266 -59.59800 11.0–10.5 BSM_S July 23, 2020 No
FM Cir 13.891000 -67.41700 12.5–11.2 BSM_S July 23, 2020 No


(4848) George Silvis — Dec. 4, 2019, 9:22 p.m.

Released to bsm_s and bsm_berry

(4726) Kenneth Menzies — Jan. 25, 2020, 8:14 p.m.

FM Cir exposures increased to 30 sec on BVRI.

(4848) George Silvis — Jan. 27, 2020, 2:49 p.m.

csv plan mistakenly labeled 119. Changed by me.

Comments on this proposal are closed.