AN optical spectroscopic survey of the serpens main cluster: Evidence for two populations? Observations reported here were obtained at the MMT observatory, a joint facility of the university of arizona and the smithsonian institution. This paper includes data gathered with the 6.5 m magellan telescopes located at las campanas observatory, Chile.

Kristen L. Erickson, Bruce A. Wilking, Michael R. Meyer, Jinyoung Serena Kim, William Sherry, Matthew Freeman

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We have completed an optical spectroscopic survey of a sample of candidate young stars in the Serpens Main star-forming region selected from deep B, V, and R band images. While infrared, X-ray, and optical surveys of the cloud have identified many young stellar objects (YSOs), these surveys have been biased toward particular stages of pre-main sequence evolution. We have obtained over 700 moderate resolution optical spectra that, when combined with published data, have led to the identification of 63 association members based on the presence of Hα in emission, lithium absorption, X-ray emission, a mid-infrared excess, and/or reflection nebulosity. Twelve YSOs are identified based on the presence of lithium absorption alone. An additional 16 objects are classified as possible association members and their pre-main sequence nature is in need of confirmation. Spectral types along with V and R band photometry were used to derive effective temperatures and bolometric luminosities for association members to compare with theoretical tracks and isochrones for pre-main sequence stars. An average age of 2 Myr is derived for this population. When compared to simulations, there is no obvious evidence for an age spread when considering the major sources of uncertainties in the derived luminosities. However when compared to the young cluster in Ophiuchus, the association members in Serpens appear to have a larger spread in luminosities and hence ages which could be intrinsic to the region or the result of a foreground population of YSOs associated with the Aquila Rift. Modeling of the spectral energy distributions from optical through mid-infrared wavelengths has revealed three new transition disk objects, making a total of six in the cluster. Echelle spectra for a subset of these sources enabled estimates of v sin i for seven association members. Analysis of gravity-sensitive lines in the echelle and moderate resolution spectra of the association members indicate surface gravities consistent with dwarf or sub-giant stars.

Original languageEnglish (US)
Article number103
JournalAstronomical Journal
Volume149
Issue number3
DOIs
StatePublished - Mar 1 2015
Externally publishedYes

Keywords

  • ISM: individual objects (Serpens cloud)
  • open clusters and associations: general
  • stars: formation
  • stars: pre-main sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'AN optical spectroscopic survey of the serpens main cluster: Evidence for two populations? Observations reported here were obtained at the MMT observatory, a joint facility of the university of arizona and the smithsonian institution. This paper includes data gathered with the 6.5 m magellan telescopes located at las campanas observatory, Chile.'. Together they form a unique fingerprint.

Cite this