High resolution spectroscopic observations of PNV J19430751+2100204 (Nova Vul 2024)
ATel #16746; Paolo Valisa (ANS Collaboration), Ulisse Munari (INAF Padova)
on 31 Jul 2024; 10:18 UT
Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it)
PNV J19430751+2100204 was discovered by the New Milky Way survey (K.
Sokolovsky et al.) on July 29.832 UT at unfiltered 11.2 mag. The object was
not detected at a limiting mag 14.5 the night before on July 28.839 UT,
indicating a fast rise in brightness, even more so considering the
non-detection at a limiting magnitude 14.0 by T. Kojima on 29.513 UT. The
object has been classified as a reddened nova by K. Taguchi (ATel #16743)
from spectra collected on July 30.47 UT, showing broad Balmer Halpha, Hbeta,
Hgamma and OI 7774 emission lines, with P-Cyg absorption blue-shifted by
1900 km/s. Filtered photometry for
Jul 30.521 UT reported to CBAT-TOCP by K. Yoshimoto reads B =11.51, V
=9.79, Ic =7.79.
We have obtained an Echelle high resolution spectrum (range 4250-8290 Ang,
res.power 14,500) of PNV J19430751+2100204 with the Varese 0.84m telescope
on Jul 30.869 UT. Compared to Taguchi's observation of 9 hours earlier, the
emission lines have all reduced in equivalent width, with Hgamma no more visible
and Hbeta barely so, as in a nova approaching maximum brightness.
The Gaussian-like emission component of Halpha is centered at an
heliocentric velocity of -440 km/s, and on its blue wing it is present a
P-Cyg absorption component of 6.9 Ang equivalent width (E.W.). This
absorption clearly splits into two distinct components of similar E.W. at
heliocentric radial velocities of -1675 and -1270; the same
applies to the P-Cyg absorption of OI 7774, that presents two absorption
components at heliocentric velocities -1685 and -1235, for an overall E.W.
of 9.2 Ang.
The high reddening affecting the nova manifest in a rich presence of
Diffuse Interstellar Bands and very strong interstellar NaI and KI lines.
Interstellar NaI appears at an heliocentric velocity of +14(+/-1) km/s and
it is strongly saturated. KI 7699 is far from saturation and its
E.W.=0.396 Ang corresponds to E(B-V)=1.75 following Munari and Zwitter
(1997, A&A 318, 269). A similar E(B-V)=1.70 is derived from the E.W.=0.386
of DIB 6614 following the calibration of Munari (2014, ASPC 490, 18).
