# Abstract/Details

## An optical study of the faint end of the stellar luminosity function

1992 1992

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### Abstract (summary)

We implement a new method by which to study the faint end of the field star luminosity function. The method relies on deep, multicolor photometry of fields projected against highly obscured, nearby molecular clouds. The clouds act as nearly opaque screens and delimit a well-defined survey sample volume free of the problem of distinguishing nearby, intrinsically faint dwarf stars from more distant red giants. We demonstrate that with this technique it is possible to probe the faint end of the field star luminosity function down to the hydrogen-burning main sequence out to distances much further than have been previously attempted.

This study is based upon deep photographic and CCD photometry at optical (V, R, I) bandpasses towards the most obscured portions of the Taurus and Ophiuchus molecular clouds. The fields comprise a total area of $\sim$0.63 square degrees, and the total volume delimited by the cloud distances is $\sim$198 pc$\sp3.$ Within this volume, the survey is complete for all stars brighter than M$\sb{\rm v}$ = 16-17 mag; at R and I, the survey is complete down to the lowest mass stars capable of sustaining core hydrogen burning.

Color-color criteria are used to distinguish between background, highly reddened stars and stars located in front of the clouds. The method of photometric parallax is used to deduce the absolute magnitude and spectral type of those stars found to lie in front of the luminosity function rises beyond M$\sb{\rm v}\sim16;$ there appears to be little double that the luminosity function at least remains flat for the lowest mass stars.

Our provisional finding that the luminosity function rises again beyond its well-known peak at M$\sb{\rm v}\sim12{-}13,$ also implies that the IMF probably rises beyond the turnover point associated with this peak. The IMF must at least remain flat down to the edge of the hydrogen-burning main sequence.

### Indexing (details)

Subject
Astronomy;
Astrophysics
Classification
0606: Astronomy
0606: Astrophysics
Identifier / keyword
Pure sciences; luminosity
Title
An optical study of the faint end of the stellar luminosity function
Author
Jarrett, Thomas Harold
Number of pages
347
Publication year
1992
Degree date
1992
School code
0118
Source
DAI-B 53/02, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
Dickman, Robert L.
University/institution
University of Massachusetts Amherst
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
9219451
ProQuest document ID
304014061