Post on 28-Dec-2015
V1309 ScoNova Scorpii 2008
Elena Mason, Robert Williams, Marcus Diaz
ESO-ChileSTCI
IAG University of Sao Paulo
The FEROS nova survey
Jun 2003-Feb 2006 (ESO periods 71-76): 14 CNe; 2-12 epochs per object;
La Silla 2.2+FEROS: λ-range ~400-900nm; R~48000
[Williams et al. 2008, ApJ, 685, 451]
The THEA (Transient Heavy Elements Absorption) system
The THEA (Transient Heavy Elements Absorption) system
• s-elements (Fe, Ti, Sc, V, Cr, Y, Sr, Zr)• low velocities (~500 km/s)• low dispersion velocities (35-300 km/s)• disappear ~1 month after the nova outburst• are external to the CN expanding ejecta
[Williams et al. 2008, ApJ, 685, 451]
Discovery of V1309 Sco
• narrow H emission lines (FWHM~670 & 300 km/s)
• absorption lines• no P-Cyg absorption
SOAR spectrum at Cerro Pochon:• red continuum and colors: B=9.2 V=7.8
R=7.3 mag• pre-outburst mag ~14.8
ESO DDT at UT2+UVESdic1 436+580 & dic2 437+860 3000 – 10400 A
slit 0.7” & 1.0” R~70000 – 500005 epochs (Sep 13 to Oct 20)
__V1309 Sco __ Nova LMC 2005
• singly ionized s-elements + FeI, CrI, …• low velocity (~-50 km/s with respect to systemic)• low dispersion velocities (FWHM~30 km/s)
V1309 Sco: __ epoch 1 __ epoch 5
__ epoch 1, __ epoch 5__ FeII (49) 5477.7 & FeI (15)5497.5
FeII (41) 5384.1 (46) 5991.4 (40) 6432.7 & (74) 6456.4
Balmer emission lines evolution
The Balmer lines:
• double peaked profile …absorption + emission• narrow: emission ~140 km/s absorption ~ 70 km/s• small relative velocity with respect to systemic (~50 km/s) • “burst” at late epochs
Spectroscopic characteristics - summary:
Absorption phase spectra (epochs 1-3):
• Enormous amount of abs. lines from FeI, FeII, TiII, VII, ScII, SrII, YII, CrI, CrII, CaI, MnI and MgI
• strong & narrow H Balmer in emission with complex profiles
• continuum possibly consistent with a K type star
Emission line phase spectra (epochs 4 & 5):
• FeII, FeI, TiII etc. absorption lines now in emission
• He I, OI, NI, [OI]• stronger H Balmer lines (by
a factor up to a few 100s)• fainter but redder
continuum
• + [CaII] emission at 7291 & 7323 A
What is it?
• not a “classical” CN (spc. evolution & line velocities)• not an AGB or post-AGB (outburst amplitude)• not a symbiotic (giant at 13kpc toward the GC?)• not a born again AGB (spc evolution …)
• cooler continuum• s-element absorption red nova (V838 Mon, V4332 Sgr …type)• narrow H emission
• ?• planet/stellar merging (Retter & Marom ‘03, Tylenda &
Soker ‘06)• 50000 K Wolf Rayet “outburst” (Munari et al. ‘05)
• CN on a low mass WD (Iben & Tutukov ‘92)
but …?
V1309 Sco:
• H + low & high ionization element emission lines
• A~7 mag• how is it evolving?
red novae:
• Just Balmer emission lines emission which soon “turned off”
• A ≥ 9-10 mag
failed nova
HeI profiles (multiplets 48, 4, 11, 46 & 10):
[OI](1) & [CaII](1):
CaI & NaI evolution