**Table 1:** Basic parameters of the sample stars. In Cols. 1 and 2 we give the index number by which a star can be identified in tables and figures throughout this work, and the name of the star, respectively. The classification of the sources according to ME01 is listed in the third column. In Col. 5 the distances, derived from direct (Hipparcos) parallax measurements or by association to a star forming region (SFR, Col. 4), are given. For the stars where the distance is determined by association with a SFR we assume an error of 30% in the distance. The spectral type according to the MK classification, the effective temperature and the stellar luminosity are given in Cols. 6-8, respectively. Mass and age estimates for most stars, as derived by comparing their positions in the HR diagram to theoretical pre-main-sequence tracks, are given in Cols. 9 and 10. For HD 101412 we have no reliable distance estimate, and can therefore not determine its luminosity, mass and age.
(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
#	Star	Group	SFR	d	Sp. type	log ${T_{\rm eff}}$	log L	Mass	log(age)
				[pc]		[K]	[ $\ensuremath{{L}_{\odot}}$ ]	[ $\ensuremath {{M}_{\odot }}$ ]	[yr]
1	AB Aur	Ia	L519	$144_{\rm - 17}^{ + 22}$	A0Ve+sh	3.979	1.67	2.4 $\pm$ 0.2	6.3 $\pm$ 0.2
2	UX Ori	IIa	Orion OB1a	$340\pm 102$	A4IVe	3.925	1.68	2.5 $\pm$ 0.3	6.3 $\pm$ 0.4
3	HD 36112	Ia		$204_{\rm - 39}^{ + 63}$	A5IVe	3.911	1.35	2.0 $\pm$ 0.3	6.5 $\pm$ 0.3
4	HK ORI	IIa	Orion OB1a	$340\pm 102$	A4pevar	3.927	0.87	1.7 $\pm$ 0.3	>6.8
5	HD 245185	Ia	Orion OB1a	$340\pm 102$	A0Ve	3.979	1.26	2.2 $\pm$ 0.3	>6.8
6	V380 Ori	IIa	Orion OB1c	$510\pm 153$	A1:e	3.965	1.88	2.8 $\pm$ 0.5	6.2 $\pm$ 0.4
7	HD 37357	IIa		$240\pm 72^1$	A2Ve	4.021	1.47	2.4 $\pm$ 0.4	>7.0
8	HD 37806	IIa	Orion OB1b	$470\pm 141$	A2Vpe	3.953	2.13	3.6 $\pm$ 0.8	5.9 $\pm$ 0.4
9	HD 95881	IIa	Sco OB2-4?	$118\pm 35$	A2III/IVe	3.954	0.88	1.7 $\pm$ 0.2	>6.5
10	HD 97048	Ib	Ced 111	$175_{\rm - 20}^{ + 26}$	B9.5Ve+sh	4.000	1.64	2.5 $\pm$ 0.2	>6.3
11	HD 100453	Ib		$111_{\rm - 8}^{ + 10}$	A9Ve	3.869	0.90	1.7 $\pm$ 0.2	7.0 $\pm$ 0.1
12	HD 100546	Ia	Sco OB2-4?	$103_{\rm - 6}^{ + 6}$	B9Vne	4.021	1.51	2.4 $\pm$ 0.1	>7.0
13	HD 101412	IIa			B9.5V
14	HD 104237	IIa	Cha III	$116_{\rm - 6}^{ + 7}$	A4IVe+sh	3.925	1.54	2.3 $\pm$ 0.1	6.3 $\pm$ 0.1
15	HD 135344	Ib	Sco OB2-3	$140\pm 42$	F4Ve	3.819	0.91	1.6 $\pm$ 0.2	6.9 $\pm$ 0.3
16	HD 139614	Ia	Sco OB2-3	$140\pm 42$	A7Ve	3.895	0.91	1.7 $\pm$ 0.3	>7.0
17	HD 142666	IIa	Sco OB2-2	$145\pm 43$	A8Ve	3.880	1.13	1.8 $\pm$ 0.3	6.8 $\pm$ 0.4
18	HD 142527	Ia		$198_{\rm - 37}^{ + 60}$	F7IIIe	3.796	1.46	2.5 $\pm$ 0.3	6.0 $\pm$ 0.4
19	HD 144432	IIa	Sco OB2-2	$145\pm 43$	A9IVev	3.866	1.01	1.8 $\pm$ 0.2	7.0 $\pm$ 0.3
20	HD 144668	IIa	Lupus 3	$207_{\rm - 31}^{ + 45}$	A5-7III/IVe	3.899	1.94	3.2 $\pm$ 0.5	5.7 $\pm$ 0.3
21	HD 150193	IIa	Sco OB2-2	$150_{\rm - 30}^{ + 50}$	A2IVe	3.953	1.38	2.3 $\pm$ 0.2	>6.3
22	HD 163296	IIa		$122_{\rm - 13}^{ + 16}$	A3Ve	3.941	1.38	2.0 $\pm$ 0.2	6.7 $\pm$ 0.4
23	HD 169142	Ib	Sco OB2-1	$145\pm 43$	A5Ve	3.914	1.16	2.0 $\pm$ 0.3	6.9 $\pm$ 0.3
24	HD 179218	Ia	(L693)	$243_{\rm - 43}^{ + 68}$	B9e	4.021	2.00	2.9 $\pm$ 0.5	6.1 $\pm$ 0.4