1 Introduction

This paper continues a series dedicated to presenting CCD UBVRI photometry for all the known and/or suspected open clusters in the Carina complex (Janes et al. 1988). According to Feinstein (1995) the region around $\eta$ Carinae contains 14 open clusters, some of which still remain very poorly studied. For most of them no CCD photometry was available when we started our survey.

In Carraro et al. (2001) we discussed NGC 3324 and Loden 165, concluding that the latter has probably no relation with the Carina Complex, being much older and closer to the Sun than the bulk of the other clusters.

In Patat & Carraro (2001) we studied Bochum 9, 10 and 11, suggesting that Bochum 9 is a doubtful object, while Bochum 10 and 11 are two young and poorly populated open clusters.

In this work we present results for NGC 3114, Collinder 228 and vdB-Hagen 99, for which to our knowledge no multicolor CCD photometry is available.

The aim is to provide accurate photometry for all these clusters, in order to derive precise age estimates. This is important to infer global properties and to study the clusters formation history in the very interesting Carina region.

The layout of the paper is as follows: Sect. 2 presents very briefly the data acquisition and reduction. In Sect. 3 we discuss the open cluster NGC 3114. Section 4 is dedicated to Collinder 228, whereas Sect. 5 deals with vdB-Hagen 99. Our conclusions are summarized in Sect. 6.

 

 

Table 1: Basic parameters of the observed objects. Coordinates are for J2000.0 equinox.

Name	$\alpha$	$\delta$	l	b
	hh:mm:ss	$^{\circ}$:$^{\prime}$: $^{\prime\prime}$	$^{\circ}$	$^{\circ}$
NGC 3114	10:02:42.7	-60:06:32.1	283.34	-3.83
Collinder 228	10:43:01.3	-60:00:44.8	287.52	-1.04
vdB-Hagen 99	10:37:54.2	-59:11:37.1	286.56	-0.63

 

 

Table 2: Journal of observations of NGC 3114 (April 13, 1996), Collinder 228 (April 14, 1996), and vdB-Hagen 99 (April 15, 1996).

	NGC 3114			Collinder 228			vdB-Hagen 99
Field	Filter	Exp. Time	Seeing	Field	Filter	Exp. Time	seeing	Field	Filter	Exp. Time	seeing	Field	Filter	Exp. Time	seeing
		(s)	( $\prime\prime$)			(s)	( $\prime\prime$)			(s)	( $\prime\prime$)			(s)	( $\prime\prime$)
$\char93 1$	U	1200	2.0	$\char93 1$				$\char93 1$				$\char93 3$
	U	120	1.8		U	60	2.0		U	180	2.3		U	300	1.7
	B	10	1.7		B	10	2.0						B	30	1.6
	B	900	1.7		B	300	1.6		B	30	2.1		B	300	1.5
	V	20	1.5		V	3	1.7						V	20	1.6
	V	300	1.6		V	120	1.8		V	15	2.0		V	120	1.6
	R	10	1.5		R	3	1.7						R	5	1.6
	R	180	1.4		R	60	1.8		R	10	1.9		R	120	1.6
	I	5	1.3		I	5	1.8						I	5	1.5
	I	300	1.3		I	120	1.6		I	20	1.7		I	120	1.6
$\char93 2$	U	60	1.5	$\char93 2$				$\char93 2$	U	300	2.4
	U	1200	1.6		U	60	1.6		U	60	2.0
	B	10	1.4		B	10	1.6		B	300	2.3
	B	900	1.4		B	300	1.8		B	30	2.3
	V	10	1.4		V	3	2.0		V	120	2.1
	V	300	1.5		V	120	2.0		V	10	2.0
	R	5	1.4		R	3	1.8		R	5	1.8
	R	180	1.2		R	60	1.9		R	120	1.8
	I	10	1.2		I	5	1.9		I	120	1.8
	I	300	1.3		I	120	2.0		I	5	1.8