Search for 7Be in the outbursts of four recent novae
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Search for 7Be in the outbursts of four recent novae. / Molaro, P.; Izzo, L.; Bonifacio, P.; Hernanz, M.; Selvelli, P.; della Valle, M.
In: Monthly Notices of the Royal Astronomical Society, Vol. 492, No. 4, 03.2020, p. 4975-4985.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Search for 7Be in the outbursts of four recent novae
AU - Molaro, P.
AU - Izzo, L.
AU - Bonifacio, P.
AU - Hernanz, M.
AU - Selvelli, P.
AU - della Valle, M.
PY - 2020/3
Y1 - 2020/3
N2 - Following the recent detection of Be-7 II in the outburst spectra of classical novae, we report the search for this isotope in the outbursts of four recent bright novae by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations. The Be-7 II lambda lambda 313.0583,313.1228 nm doublet resonance lines are detected in the high-velocity components of Nova Mus 2018 and ASASSN-18fv during outbursts. However, 7Be?II is not detected in ASASSN-17hx and possibly not in Nova Cir 2018, which shows that 7Be is not always ejected in the thermonuclear runaway. Taking into account the Be-7 decay, we find X(Be-7)/X(H) approximate to 1.5 x 10(-5) and 2.2 x 10(-5) in Nova Mus 2018 and ASASSN-18fv, respectively. A value of 7Be/H approximate to 2 x 10(-5) is found in five out of the seven extant measurements, and it can be considered as a typical 7Be yield for novae. However, this value is almost one order of magnitude larger than predicted by current theoretical models. We argue that the variety of high Be-7/H abundances could be the result of a higher than solar content of 3He in the donor star. The cases with Be-7 not detected might be related to the small mass of the white dwarf (WD) or to relatively little mixing with the core material of the WD. The Be-7/H, or Li-7/H, abundance is approximate to 4 dex above meteoritic abundance, thus confirming the novae as the main sources of Li-7 in the Milky Way.
AB - Following the recent detection of Be-7 II in the outburst spectra of classical novae, we report the search for this isotope in the outbursts of four recent bright novae by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations. The Be-7 II lambda lambda 313.0583,313.1228 nm doublet resonance lines are detected in the high-velocity components of Nova Mus 2018 and ASASSN-18fv during outbursts. However, 7Be?II is not detected in ASASSN-17hx and possibly not in Nova Cir 2018, which shows that 7Be is not always ejected in the thermonuclear runaway. Taking into account the Be-7 decay, we find X(Be-7)/X(H) approximate to 1.5 x 10(-5) and 2.2 x 10(-5) in Nova Mus 2018 and ASASSN-18fv, respectively. A value of 7Be/H approximate to 2 x 10(-5) is found in five out of the seven extant measurements, and it can be considered as a typical 7Be yield for novae. However, this value is almost one order of magnitude larger than predicted by current theoretical models. We argue that the variety of high Be-7/H abundances could be the result of a higher than solar content of 3He in the donor star. The cases with Be-7 not detected might be related to the small mass of the white dwarf (WD) or to relatively little mixing with the core material of the WD. The Be-7/H, or Li-7/H, abundance is approximate to 4 dex above meteoritic abundance, thus confirming the novae as the main sources of Li-7 in the Milky Way.
KW - nuclear reactions, nucleosynthesis, abundances
KW - stars: individual: ASASSN-17hx
KW - stars: individual: Nova Mus 2018
KW - stars: individual: Nova Cir 2018
KW - stars: individual: ASASSN-18fv
KW - novae
KW - Galaxy: evolution
KW - EXPLOSIVE THERMONUCLEAR FORMATION
KW - GALACTIC EVOLUTION
KW - STELLAR EVOLUTION
KW - CLASSICAL NOVAE
KW - LI-7
KW - HE-3
KW - EMISSION
KW - NUCLEOSYNTHESIS
KW - CATALOG
KW - LITHIUM
U2 - 10.1093/mnras/stz3587
DO - 10.1093/mnras/stz3587
M3 - Journal article
VL - 492
SP - 4975
EP - 4985
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 4
ER -
ID: 247938648