A Multi-color Optical Survey of the Orion Nebula Cluster. II. the H-R diagram

Details A Multi-color Optical Survey of the Orion Nebula Cluster. II. the H-R diagram A Multi-color Optical Survey of the Orion Nebula Cluster. II. the H-R diagram

2010-08-06

arxiv.org/abs/1008.1265v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

24 pages, 23 Figures, accepted for publication in the Astrophysical Journal Supplement Series

Scientific paper

We present a new analysis of the stellar population of the Orion Nebula Cluster (ONC) based on multi-band optical photometry and spectroscopy. We study the color-color diagrams in BVI, plus a narrow-band filter centered at 6200A, finding evidences that intrinsic color scales valid for main-sequence dwarfs are incompatible with the ONC, while a better agreement is found employing synthetic intrinsic colors obtained constraining the typical lower surface gravity of young stars. We refine these model colors even further, empirically, by comparison with a sample of ONC stars with no accretion and no extinction. We consider the stars with known spectral types from the literature, and add 65 newly classified stars from slit spectroscopy and 182 M-type from narrow-band photometry; in this way we isolate a sample of about 1000 stars with known spectral type. We introduce a new method to self-consistently derive reddening and accretion excess from the location of each star in the BVI color-color diagram. This enables us to accurately determine the extinction of the ONC members. We adopt a lower distance for the ONC than previously assumed, based on recent parallax measurements. With a careful choice also of the spectral type-temperature transformation, we produce the new H-R diagram of the ONC population, more populated than previous works. With respect to previous works, we find higher luminosity for late-type stars and a lower luminosity for early types. We determine the age distribution of the population, peaking at 2-3 Myr, a higher age than previously estimated. We study the distribution of the members in the mass-age plane, and find that taking into account selection effects due to incompleteness removes an apparent correlation between mass and age. We derive the IMF for low- and intermediate-mass members of the ONC, which turns out to be model-dependent, and shows a turn-over at ~<0.2Msun.

Affiliated with

Also associated with

No associations

Rating

A Multi-color Optical Survey of the Orion Nebula Cluster. II. the H-R diagram does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A Multi-color Optical Survey of the Orion Nebula Cluster. II. the H-R diagram, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Multi-color Optical Survey of the Orion Nebula Cluster. II. the H-R diagram will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-592636