**Table 5:** Polarization and infrared emission data for gas-rich comets observed at large phase angles.
Comet name	$\alpha_{\rm obs}^{1}$	Diaphragm size	$P_{\rm obs}^{2}$	$P_{\rm dust}^{3}$	Polar.	Overheat/silicate	Ref.⁴
	( $^{\circ}$ )	or box (km²)	(%)	(%)	class	features at 10 $\mu$ m
C/1975 N1 (Kobayashi-	95.4	$\pi \times 38360^2$	9.1	25.9	low	1.08/no	1, 2
Berger-Milon)
23P/Brorsen-Metcalf	86.0	$\pi \times 37660^2$	15.3	25.2	low	1.05/no	1, 3
C/1982 M1 (Austin)	94.1	$\pi \times 45000^2$	9.1	25.9	low	?/?	4, -
	98	2452 $~\times~$ 5655	22.3	25.8	high		5, -
C/1983 H1 (Iras-	92.5	$\pi \times 800^2$	32	25.8	high	1.07/very weak	6, 7
Araki-Alcock)
27P/Crommelin	73.7	$\pi \times 28760^2$	11.3	22.2	low	<1.04/no	1, 8
C/1989 X1 (Austin)	89.3	$\pi \times 5400^2$	18.0	25.6	low	1.07-1.20/weak	9, 10
C/1989 Q1 (Okazaki-	89.8	$\pi \times 3630^2$	16.0	25.6	low	1.20/no	11, 7
Levy-Ludenko)
D/1996 Q1 (Tabur)	83.3	990 $~\times~$ 990	25.4	24.7	high	$\approx$ 1.05/weak	12, 13
		7422 $~\times~$ 7422	15.9		low
2P/Encke	94.6	$582 \times 582$	$\ge$ 30	25.9	high	1.03/weak	14, 15
		$\approx$ 3000 $~\times~$ 4500	7.7		low
21P/Giacobini-Zinner	62.3	35 300 $\times$ 35 300	15.7	17.6	high	weak/weak	16, 17

¹⁾ Observed phase angle.
²⁾ Observed degree of polarization.
³⁾ Polarization of a typical dusty comet at phase angle $\alpha_{\rm obs}$ .
⁴⁾ References: (1) Chernova et al. (1993); (2) Ney (1982); (3) Lynch et al. (1992); (4) Rosenbush et al. (1997);
   (5) Myers & Nordsiek (1984); (6) Kikuchi (1983); (7) Hanner et al. (1994); (8) Hanner et al. (1985);
   (9) Kikuchi et al. (1990); (10) Hanner et al. (1993); (11) Rosenbush et al. (1994); (12) Kiselev et al. (2001);
   (13) Harker et al. (1999); (14) This work; (15) Gehrz et al. (1989); (16) Kiselev et al. (2000);
   (17) Hanner et al. (1992).

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