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The TeV binary system \lsi has a compact object in an eccentric orbit arounda Be star about 2 kpc from Earth. \lsi exhibits modulated gamma-ray emissionaround its 26.5 days orbit, mostly detectable at TeV energies around itsapastron passage, with maximum flux during the $\phi = 0.55-0.65$ phase range.Multiple flaring episodes with nightly flux variability at TeV energies havebeen observed since its detection in 2006. At one time significant TeV emissionwas also detected in late 2010 from the source close to its periastron passageat superior conjunction. The TeV spectrum is well fitted by a power law withsmall variations of spectral index of $\sim2.6$ over the years. GeV, X-ray, andradio emission have been detected along the entire orbit, enabling detailedstudy of the modulation pattern and its super-orbital period, suchcomprehensive study of the \lsi orbit in the TeV regime has not been presentedbefore. VERITAS has observed \lsi for over a decade now, accruing 200+ hours ofdata during different parts of its orbit. In this work, we have analyzed allavailable data for \lsi since September 2007 in individual phase bins of width$\Delta \phi = 0.1$ and performed a spectral analysis for two different partsof the orbit. TeV emission is now detected in 9 out of 10 phase bins, aroundthe entire orbit for the first time in VERITAS data. Hint of spectral variationmight also be present between different parts of the orbit. The implication ofthese results is discussed in the context of determining the nature of theunknown compact object (neutron star or microquasar) and a discussion of theabsorption mechanisms in the system.

Decadal VERITAS Observation of LS I +61$^{\circ}$303 : Detection of TeV emission around the entire orbit