TY - JOUR

T1 - Be-7 in the outburst of the ONe nova V6595 Sgr

AU - Molaro, P.

AU - Izzo, L.

AU - D'Odorico, Valentina

AU - Aydi, E.

AU - Bonifacio, P.

AU - Cescutti, G.

AU - Harvey, E. J.

AU - Hernanz, M.

AU - Selvelli, P.

AU - della Valle, M.

PY - 2021/11/26

Y1 - 2021/11/26

N2 - We report on the search for the Be-7 ii isotope in the outbursts of the classical nova V6595 Sgr by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations taken at the European Southern Observatory's Very Large Telescope in 2021 April, about two weeks after its discovery and under difficult circumstances due to the pandemic. Narrow absorption components with velocities at similar to -2620 and -2820 km s(-1), superposed on broader and shallow absorption, are observed in the outburst spectra for the Be-7 ii lambda lambda 313.0583, 313.1228 nm doublet resonance lines, as well as in several other elements such as Ca ii, Fe i, Mg i, Na i, H i and Li i. Using the Ca ii K line as a reference element, we infer N(Be-7)/N(H) approximate to 7.4 x 10(-6), or approximate to 9.8 x 10(-6) when the Be-7 decay is taken into account. The Be-7 abundance is about half of the value most frequently measured in novae. The possible presence of overionization in the layers where Be-7 ii is detected is also discussed. Observations taken at the Telescopio Nazionale Galileo in La Palma 91 days after discovery showed prominent emission lines of oxygen and neon, which allow us to classify the nova as ONe type. Therefore, although Be-7 is expected to be higher in CO novae, it is found at comparable levels in both nova types.

AB - We report on the search for the Be-7 ii isotope in the outbursts of the classical nova V6595 Sgr by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations taken at the European Southern Observatory's Very Large Telescope in 2021 April, about two weeks after its discovery and under difficult circumstances due to the pandemic. Narrow absorption components with velocities at similar to -2620 and -2820 km s(-1), superposed on broader and shallow absorption, are observed in the outburst spectra for the Be-7 ii lambda lambda 313.0583, 313.1228 nm doublet resonance lines, as well as in several other elements such as Ca ii, Fe i, Mg i, Na i, H i and Li i. Using the Ca ii K line as a reference element, we infer N(Be-7)/N(H) approximate to 7.4 x 10(-6), or approximate to 9.8 x 10(-6) when the Be-7 decay is taken into account. The Be-7 abundance is about half of the value most frequently measured in novae. The possible presence of overionization in the layers where Be-7 ii is detected is also discussed. Observations taken at the Telescopio Nazionale Galileo in La Palma 91 days after discovery showed prominent emission lines of oxygen and neon, which allow us to classify the nova as ONe type. Therefore, although Be-7 is expected to be higher in CO novae, it is found at comparable levels in both nova types.

KW - nuclear reactions

KW - nucleosynthesis

KW - abundances

KW - stars: abundances

KW - stars: individual: V6595 Sgr

KW - novae

KW - cataclysmic variables

KW - Galaxy: evolution

KW - GAMMA-RAY LINES

KW - V5668 SGR

KW - LITHIUM

KW - LI-7

KW - EVOLUTION

KW - EMISSION

KW - GIANT

KW - ABSORPTION

KW - ELEMENTS

KW - ORIGIN

U2 - 10.1093/mnras/stab3106

DO - 10.1093/mnras/stab3106

M3 - Journal article

VL - 509

SP - 3258

EP - 3267

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 3

ER -