The White Dwarf Population In NGC 1039 (M34) And The White Dwarf Initial-Final Mass Relation

dc.contributor.utaustinauthorWilliams, Kurtis A.en_US
dc.creatorRubin, Kate H. R.en_US
dc.creatorWilliams, Kurtis A.en_US
dc.creatorBolte, M.en_US
dc.creatorKoester, Detleven_US
dc.description.abstractWe present the first detailed photometric and spectroscopic study of the white dwarfs (WDs) in the field of the similar to 225 Myr old (log tau(cl) = 8.35) open cluster NGC 1039 (M34) as part of the ongoing Lick-Arizona White Dwarf Survey. Using wide-field UBV imaging, we photometrically select 44 WD candidates in this field. We spectroscopically identify 19 of these objects as WDs; 17 are hydrogen-atmosphere DA WDs, one is a helium-atmosphere DB WD, and one is a cool DC WD that exhibits no detectable absorption lines. We find an effective temperature (T(eff)) and surface gravity (log g) for each DA WD by fitting Balmer-line profiles from model atmospheres to the observed spectra. WD evolutionary models are then invoked to derive masses and cooling times for each DA WD. Of the 17 DAs, five are at the approximate distance modulus of the cluster. Another WD with a distance modulus 0.45 mag brighter than that of the cluster could be a double-degenerate binary cluster member, but is more likely to be a field WD. We place the five single cluster member WDs in the empirical initial-final mass relation and find that three of them lie very close to the previously derived linear relation; two have WD masses significantly below the relation. These outliers may have experienced some sort of enhanced mass loss or binary evolution; however, it is quite possible that these WDs are simply interlopers from the field WD population. Eight of the 17 DA WDs show significant Ca II K absorption; comparison of the absorption strength with the WD distances suggests that the absorption is interstellar, though this cannot be confirmed with the current data.en_US
dc.identifier.citationRubin, Kate HR, Kurtis A. Williams, M. Bolte, and Detlev Koester. >The White Dwarf Population in NGC 1039 (M34) and the White Dwarf Initial-Final Mass Relation.> The Astronomical Journal, Vol. 135, No. 6 (Jun., 2008): 2163.en_US
dc.relation.ispartofserialAstronomical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectopen clusters and associations : individual (ngc 1039)en_US
dc.subjectwhite dwarfsen_US
dc.subjectwiyn open clusteren_US
dc.subjectluminosity functionen_US
dc.subjectspectroscopic identificationen_US
dc.subjecttheoretical isochronesen_US
dc.subjecty-2 isochronesen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleThe White Dwarf Population In NGC 1039 (M34) And The White Dwarf Initial-Final Mass Relationen_US

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