THE DISK POPULATION OF THE TAURUS STAR-FORMING REGION

By K. Luhman, P. R. Allen, Catherine C. Espaillat, L. Hartmann, N. Calvet. 2009

343 citations recorded by the source corpus.

We have analyzed nearly all images of the Taurus star-forming region at 3.6, 4.5, 5.8, 8.0, and 24 μm that were obtained during the cryogenic mission of the Spitzer Space Telescope (46 deg2) and have measured photometry for all known members of the region that are within these data, corresponding to 348 sources, or 99% of the known stellar population. By combining these measurements with previous observations with the Spitzer Infrared Spectrograph and other facilities, we have classified the members of Taurus according to whether they show evidence of circumstellar disks and envelopes (classes I, II, and III). Through these classifications, we find that the disk fraction in Taurus, N(II)/N(II+III), is ∼75% for solar-mass stars and declines to ∼45% for low-mass stars and brown dwarfs (0.01–0.3 M☉). This dependence on stellar mass is similar to that measured for Chamaeleon I, although the disk fraction in Taurus is slightly higher overall, probably because of its younger age (1 Myr versus 2–3 Myr). In comparison, the disk fraction for solar-mass stars is much lower (∼20%) in IC 348 and σ Ori, which are denser than Taurus and Chamaeleon I and are roughly coeval with the latter. These data indicate that disk lifetimes for solar-mass stars are longer in star-forming regions that have lower stellar densities. Through an analysis of multiple epochs of Spitzer photometry that are available for ∼200 Taurus members, we find that stars with disks exhibit significantly greater mid-infrared (mid-IR) variability than diskless stars, which agrees with the results of similar variability measurements for a smaller sample of stars in Chamaeleon I. The variability fraction for stars with disks is higher in Taurus than in Chamaeleon I, indicating that the IR variability of disks decreases with age. Finally, we have used our data in Taurus to refine the observational criteria for primordial, evolved, and transitional disks. The ratio of the number of evolved and transitional disks to the number of primordial disks in Taurus is 15/98 for spectral types of K5–M5, indicating a timescale of 0.15 × τprimordial ∼ 0.45 Myr for the clearing of the inner regions of optically thick disks. After applying the same criteria to older clusters and associations (2–10 Myr) that have been observed with Spitzer, we find that the proportions of evolved and transitional disks in those populations are consistent with the measurements in Taurus when their star formation histories are properly taken into account.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/366bffa3940db20c6db5872fcbcf5e2765a10310

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In Astronomy and Astrophysics

1. K. Luhman
2. S. Andrews
3. D. Wilner
4. L. Hillenbrand
5. G. Herczeg
6. A. Kraus
7. Eric Mamajek
8. T. Birnstiel

Citations in the corpus

• INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS (2013, background): “The Luhman et al. (2010b) tabulation is empirically derived and thus does not depend on synthetic colors.”
• A NEAR-INFRARED SPECTROSCOPIC STUDY OF YOUNG FIELD ULTRACOOL DWARFS (2013, methodology): “We have estimated the reddening to each of these sources by comparing their 2MASS J − K colors to the photospheric colors for young objects of their spectral types (Luhman et al. 2010).”
• AN OPTICAL SPECTROSCOPIC STUDY OF T TAURI STARS. I. PHOTOSPHERIC PROPERTIES (2014, background): “Table 9 lists the most significant changes in Taurus spectral types, relative to the compilation of spectral types by Luhman et al. (2010).”
• The Formation and Early Evolution of Low-Mass Stars and Brown Dwarfs (2012, background): “…stars and brown dwarfs in Taurus and Chamaeleon are particularly valuable because of their proximity, relatively low extinction, large sizes, lack of crowding and bright nebular emission, and the uniformity of their spectral classifications (Luhman 2008, Luhman et al. 2010, references therein).”
• X-Shooter study of accretion in Chamaeleon I (2015, background): “This object is a Class III YSO (Luhman et al. 2010) with SpT K0 (HH14), which was observed during the program Pr.Id.094.”
• UNVEILING THE STRUCTURE OF PRE-TRANSITIONAL DISKS (2010, methodology): “Karr et al. (2010) report a tentative detection of dust around LkCa 14 based on H-band scattered light images, however, LkCa 14’s emission is photospheric out to ∼24 µm (Luhman et al. 2010), making it suitable for the purposes of this work.”
• Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaporation (2010, background): “…have indicated discs evolve in a way that suggest ‘standard’ viscous evolution (Hartmann et al. 1998) for the first few Myrs (e.g. Haisch et al. 2001b), but then rapidly evolve from a disc-bearing (primor- c© 2002 RAS dial) to disc-less status (e.g. Luhman et al. 2010; Muzerolle et al. 2010).”
• THE DISK POPULATION OF THE UPPER SCORPIUS ASSOCIATION (2012, methodology): “Because their definition of transitional disks was broader and their classification criteria encompassed redder disks, Currie & Sicilia-Aguilar (2011) found a higher abundance of transitional disks in regions like Taurus than some studies (e.g., Luhman et al. 2010).”
• THE MASS DEPENDENCE BETWEEN PROTOPLANETARY DISKS AND THEIR STELLAR HOSTS (2013, methodology): “In most cases, the spectral types in Table 2 were culled from the Luhman et al. (2010) catalog (alternative references are in the table notes).”
• WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF THE EVOLUTION OF MASSIVE STAR-FORMING REGIONS (2012, background): “Their appearance has been noted in young regions of the Taurus starforming cloud by Luhman et al. (2010).”
• The M-dwarfs in Multiples (MinMs) survey – I. Stellar multiplicity among low-mass stars within 15 pc (2015, background): “† E-mail: kwardduo@asu.edu after contraction onto the main sequence (Luhman et al. 2010).”
• Dust Evolution and the Formation of Planetesimals (2016, background): “…with ages from 1Myr to tens of Myrs have been surveyed by various projects with Spitzer (e.g. Allen et al. 2004; Megeath et al. 2004; Luhman 2007; Evans et al. 2009; Gutermuth et al. 2009; Fang et al. 2009; Luhman et al. 2010; Megeath et al. 2012; Fang et al. 2013; Sicilia-Aguilar et al. 2015).”
• On the theory of disc photoevaporation (2011, background): “The frequency of these ‘transition/pretransition’ discs compared to those of primordial discs suggests that approximately 10–20 per cent of discs are in this stage (Strom et al. 1989; Skrutskie et al. 1990; Luhman et al. 2010; Ercolano et al. 2011a; Furlan et al. 2011).”
• LkCa 15: A YOUNG EXOPLANET CAUGHT AT FORMATION? (2011, background): “In Figure 4, we show the brightness and color of the individual components and the full structure as compared to free-floating stars and brown dwarfs within the Taurus star-forming region (Luhman et al. 2010).”