The physical conditions in Gomez's Hamburger (IRAS 18059-3211), a pre-MS rotating disk

Table 1:

Structure and physical conditions in the molecular disk of Gomez's Hamburger, derived from our model fitting of several CO rotational lines. Dependence on the assumed distance is given in the relevant cases. Other parameters of the modeling are also given.
Parameter	Law	Values	Comments
Outer radius		$R_{\rm out} = 3.1 \times 10^{16}$ ( $\frac{D({\rm pc})}{300}$ ) cm
Intermediate radius		$R_{\rm m} = 1.7 \times 10^{16}$ ( $\frac{D({\rm pc})}{300}$ ) cm
Inner radius		$R_{\rm in} = 3 \times 10^{15}$ ( $\frac{D({\rm pc})}{300}$ ) cm
Disk thickness	linear	H(10¹⁶ cm) = $9.5\times 10^{15}$ cm
Tangential	$V_{\rm t} \propto 1/\sqrt{r}$	$V_{\rm t}$ (10¹⁶ $\frac{D({\rm pc})}{300}$ cm) = 2.1 km s^-1
velocity	(Keplerian)	central mass: 3 ( $\frac{D({\rm pc})}{300}$ ) $M_{{\odot}}$
Temperature	$T_{\rm eq} \propto$ $1/r^{\alpha_T}$	$T_{\rm eq}$ (10¹⁶ $\frac{D({\rm pc})}{300}$ cm) = 16 K
(equator)		$\alpha_T$ = 0.3	+ increase in the edges, by a factor 3
			+ increase beyond $R_{\rm m}$ , T( $R_{\rm out}$ ) = 17 K
see text and Fig. 7			+ increase within 2 $\times$ $R_{\rm in}$ , by a factor of 2
Gas density	$n_{\rm eq} \propto 1/r^{\alpha_n}$	$n_{\rm eq}$ (10¹⁶ $\frac{D({\rm pc})}{300}$ cm) = $1.5\times 10^6$ ( $\frac{300}{D({\rm pc})}$ ) cm^-3
(equator)		$\alpha_n$ = 1	+ decrease with z, following hydrost. eq.
			+ decrease beyond $R_{\rm m}$ , $n_{\rm eq}$ ( $R_{\rm out}$ ) = 10³ cm^-3
see text and Fig. 7			+ increase within 2 $\times$ $R_{\rm in}$ , by a factor of 2
Relative abundances	constant	X(¹²CO):X(¹³CO):X(C¹⁷O) = 10^-4: $1.5\times 10^{-6}$ : $2 \times 10^{-7}$	assumed value for X(¹²CO)

Other parameters	Values	Comments
Axis inclination from the plane of the sky	6 $^\circ$	from optical and CO data
Axis inclination in the plane of the sky (PA)	85 $^\circ$	from optical and CO data
Distance	300 pc	from luminosity and mass values (Sect. 1)
LSR systemic velocity	2.5 km s^-1	from CO data