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The Greater Taurus–Auriga Ecosystem. I. There is a Distributed Older Population

Kraus, Adam L. and Herczeg, Gregory J. and Rizzuto, Aaron C. and Mann, Andrew W. and Slesnick, Catherine L. and Carpenter, John M. and Hillenbrand, Lynne A. and Mamajek, Eric E. (2017) The Greater Taurus–Auriga Ecosystem. I. There is a Distributed Older Population. Astrophysical Journal, 838 (2). Art. No. 150. ISSN 1538-4357. doi:10.3847/1538-4357/aa62a0.

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The census of Taurus–Auriga has been assembled over seven decades and inherited the biases and incompleteness of the input studies. The unusual shape of its inferred initial mass function (IMF) and the existence of isolated disk-bearing stars suggest that additional (likely disk-free) members remain to be discovered. We therefore have begun a global reassessment of the census of Taurus–Auriga that exploits new data and better definitions of youth and kinematic membership. As a first step, we reconsider the membership of all disk-free candidate members from the literature with spectral type ≥F0, 3^h50^m < α < 5^h40^m, and 14° < δ < 34°. We combine data from the literature with Keck/HIRES and UH88/SNIFS spectra to test the membership of these candidates using the positions in the Hertzsprung-Russel diagram, proper motions, radial velocities, Hα, lithium, and surface gravity. We find 218 confirmed or likely Taurus members, 160 confirmed or likely interlopers, and only 18 that lack sufficient evidence to draw firm conclusions. A significant fraction of these stars (81/218 = 37%) are not included in the most recent canonical member lists. There are few additional members to the immediate vicinity of the molecular clouds, preserving the IMFs that have been deemed anomalous in past work. Many of the likely Taurus members are instead distributed broadly across the search area. When combined with the known disk hosts, our updated census reveals two regimes: a high-density population with a high disk fraction (indicative of youth) that broadly traces the molecular clouds, and a low-density population with low disk fraction (hence likely older) that most likely represents previous generations of star formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kraus, Adam L.0000-0001-9811-568X
Herczeg, Gregory J.0000-0002-7154-6065
Rizzuto, Aaron C.0000-0001-9982-1332
Mann, Andrew W.0000-0003-3654-1602
Carpenter, John M.0000-0003-2251-0602
Mamajek, Eric E.0000-0003-2008-1488
Additional Information:© 2017. The American Astronomical Society. Received 2016 July 28; revised 2017 February 14; accepted 2017 February 14; published 2017 April 4. We thank T. Dupuy, B. Bowler, S. Andrews, and D. Jaffe for helpful discussions on the nature of Taurus–Auriga and how to best present its complexity. We also thank the referee for providing a helpful critique of the work. A.W.M. was supported through Hubble Fellowship grant 51364 awarded by STScI, which is operated by AURA for NASA, under contract NAS 5-26555. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Group:Infrared Processing and Analysis Center (IPAC), Astronomy Department
Funding AgencyGrant Number
NASA Hubble Fellowship51364
NASANAS 5-26555
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:open clusters and associations: individual (Taurus–Auriga) ; stars: formation; stars: pre-main sequence; stars: protostars
Issue or Number:2
Record Number:CaltechAUTHORS:20170407-134352558
Persistent URL:
Official Citation:Adam L. Kraus et al 2017 ApJ 838 150
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75855
Deposited By: George Porter
Deposited On:07 Apr 2017 22:36
Last Modified:15 Nov 2021 16:55

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