Ruling out unresolved binaries in five transitional disks - VLT/NACO deep 2.12 and 1.75 μm narrow-band imaging

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Table 2

Physical properties of the five stars and their disks found in the literature.

Star	SpT	K _s ¹	ΔK_s¹	Dist.	A _V	M _star	Age	Ṁ _acc ²
				(pc)		(M_⊙)	(Myr)	(M_⊙ yr^-1)

DoAr 21	K1^a	6.227	0.018	121.9 ± 5.8^b	6.2^a	1.8^a	<1^a	<10^11,^c
HD 135344B	F4^e	5.843	0.020	140 ± 42^g	0.5^e	1.7 ± 0.2^g	8 ± 4^g	5 × 10^-9^g
HR 4796A	A0ⁱ	5.769	0.023	72.8 ± 1.7^h	–	2.5ⁱ	8 ± 2ⁱ	–
T Cha⁶	G8^j^,^k	6.954	0.018	108 ± 9^l	1.7^k^,⁵	1.5^j	7^k^,⁵	4 × 10^-9^k
TW Hya⁷	K7^o	7.297	0.024	55 ± 9^h	0.0^q	0.6^r	10^p, 3^∗	8 × 10^-10^q–10^-9^y

Disk	R _disk,in ³	R _hole/gap,in ³	R _hole/gap,out ³	R _disk,out ³	i	PA	M _disk ⁴	Class & disk type⁵
	SED, obs.	SED, obs.	SED, obs.	SED, obs.
	(AU)	(AU)	(AU)	(AU)	(deg)	(deg)	(M_⊙)

DoAr 21	–	–	–, 100^a	–	<45^d	–	<0.001^c	PMS circumbinary/debris^c
HD 135344B	0.18^e, 0.05 ± 0.25^w	0.45^e, 1.8 ± 0.2^w	45^e, 39 ± 4^f	300^e, 160^g	21^f	55^f	(2.8 ± 1.3) × 10^-3^,^g	PMS Herbig^g
HR 4796A	–	–	40–200ⁱ, 69ⁱ	–, 87ⁱ	75.88 ± 0.16ⁱ	27.01 ± 0.16ⁱ	≥7.4 × 10^−5,ⁱ	Herbig debris diskⁱ
T Cha⁶	0.08^e 0.13ⁿ, –	0.2^e 0.17ⁿ, –	15^e 7.5ⁿ, –	300^e^,ⁿ, –	75^j, 60ⁿ	ⁿ	0.003^m, (1.76 ± 0.25) × 10^-2^,ⁿ	WTT^z
TW Hya⁷	~0.02^r, –	0.25^t, 0.06^u	4^r, 4.3 ± 0.3^s	230^x	4.3 ± 1.0^v,1, 7 ± 1^v,2	332 ± 10^v	~0.06^r	CTT^∗

Notes.

⁽¹⁾

From 2MASS;

⁽²⁾

average accretion rate derived from Hα line emission for DoAr 21 and T Cha, Brγ line emission for TW Hya (y) and HD 135344B (g), and excess Balmer continuum for TW Hya (q);

⁽³⁾

radius from the primary derived from both SED fitting models and spatially resolved observations in the optical to the sub-mm/mm. In this work we adopt the latter values when available;

⁽⁴⁾

total disk masses estimated from mm fluxes assuming a gas-to-dust ratio of 100 or 77 for TW Hya. T Cha: the first value is that of the 3 mm emission flux for a distance of 66 pc. Because M_disk ∝ d², a value of 0.008 M_⊙ is expected for the assumed distance d = 108 pc. The second value was derived from model fitting to the observed SED and H and K-band interferometric observations with the VLTI/AMBER instrument;

⁽⁵⁾

young stellar object (YSO) evolutionary class and disk type found in the literature: pre-main sequence (PMS), weak lined T Tauri (WTT) and classical T Tauri (CTT) star;

⁽⁶⁾

T Cha shows variable circumstellar extinction A_v = 1.2–4.6 and an age of 4.1–10 Myr (Schisano et al. 2009, and references therein). Here we adopt the most frequent value A_v = 1.7 and age of 7 Myr. The disk inner hole size adopted is from Brown et al. (2007);

⁽⁷⁾

a recent work by *Vacca & Sandell (2011) based on near-infrared spectroscopy revises the spectral type and age of TW Hya to M2.5 (instead of K7) and ~3 Myr (instead of 8–10 Myr). Akeson et al. (2011) combines new near-IR interferometric data with previous spatially resolved observations at 10 μm and 7 mm to constrain disk models based on a flared disk structure. They find TW Hya fits a three-component model composed by an optically thin emission from ~0.02 AU to ~0.5 AU, an optically thick ~0.1 AU wide ring that is followed by an opacity gap, and an outer optically thick disk starting at 3.8–4.5 AU. Here we adopt the values of 0.5 AU and 4.3 AU for the inner and outer hole/gap radius, respectively.

References.

^(a)

Jensen et al. (2009);

^(b)

Loinard et al. (2008);

^(c)

Cieza et al. (2010, 2008);

^(d)

Bary et al. (2002);

^(e)

Brown et al. (2007);

^(f)

Brown et al. (2009);

^(g)

Grady et al. (2009) and references therein;

^(h)

van Leeuwen (2007);

⁽ⁱ⁾

Schneider et al. (1999, 2009), Jura et al. (1995), Besla & Wu (2007) and references therein;

^(j)

Alcala et al. (1993);

^(k)

Schisano et al. (2009);

^(l)

Torres et al. (2008);

^(m)

Lommen et al. (2007);

⁽ⁿ⁾

Olofsson et al. (2011);

^(o)

Herbig (1978);

^(p)

Webb et al. (1999);

^(q)

Herczeg et al. (2009);

^(r)

Calvet et al. (2002);

^(s)

Hughes et al. (2007);

^(t)

Thi et al. (2010);

^(u)

Eisner et al. (2006);

^(v,1)

Pontoppidan et al. (2008) for the inner disk;

^(v,2)

Qi et al. (2004) for the outer disk;

^(w)

Fedele et al. (2008);

^(x)

Weinberger et al. (2002);

^(y)

Eisner et al. (2010);

^(z)

Alcala et al. (1993).

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