A Spitzer Space Telescope Study of Disks in the Young σ Orionis Cluster

By Jesús Hernández, J. Hernández, L. Hartmann, T. Megeath, R. Gutermuth, J. Muzerolle, N. Calvet, A. K. Vivas, C. Briceño, L. Allen and 3 more. 2007

400 citations recorded by the source corpus.

We report new Spitzer Space Telescope observations, using the IRAC and MIPS instruments, of the young (~3 Myr) σ Orionis cluster. We identify 336 stars as members of the cluster, using optical and near-infrared color-magnitude diagrams. Using the spectral energy distribution slopes in the IRAC spectral range, we place objects into several classes: non-excess stars, stars with optically thick disks (such as classical T Tauri stars), class I (protostellar) candidates, and stars with "evolved disks"; the last exhibit smaller IRAC excesses than optically thick disk systems. In general, this classification agrees with the location expected in IRAC-MIPS color-color diagrams for these objects. We find that the evolved disk systems are mostly a combination of objects with optically thick but nonflared disks, suggesting grain growth and/or settling, and transition disks, systems in which the inner disk is partially or fully cleared of small dust. In all, we identify seven transition disk candidates and three possible debris disk systems. As in other young stellar populations, the fraction of disks depends on the stellar mass, ranging from ~10% for stars in the Herbig Ae/Be mass range (>2 M☉) to ~35% for those in the T Tauri mass range (1-0.1 M☉). The IRAC infrared excesses found in stellar clusters and associations with and without central high-mass stars are similar, suggesting that external photoevaporation is not very important in many clusters. Finally, we find no correlation between the X-ray luminosity and the disk infrared excess, suggesting that the X-rays are not strongly affected by disk accretion.

Subfields: Astronomy and Astrophysics, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/5079d894f18ccd442f7580174ed8d158c00206a7

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In Astronomy and Astrophysics

1. K. Luhman
2. L. Hillenbrand
3. Eric Mamajek
4. S. Andrews
5. L. Hartmann
6. P. Myers
7. N. Calvet
8. A. Kraus

In Spectroscopy

1. K. Luhman
2. P. Myers
3. L. Hartmann
4. L. Hillenbrand
5. L. Allen
6. R. Gutermuth
7. J. Muzerolle
8. N. Calvet

Citations in the corpus

• A Spitzer View of Protoplanetary Disks in the γ Velorum Cluster (2008, methodology): “Figure 11 shows the disk frequencies of late type stars (stars K middle or later) with near-infrared disk emission in different stellar groups, as a function of age (Hernández et al. 2005, 2007a; Haisch et al. 2001).”
• LARGE-SCALE ASYMMETRIES IN THE TRANSITIONAL DISKS OF SAO 206462 AND SR 21 (2014, neutral): “In a few million years an optically thick massive protoplanetary disk will transform into an optically thin debris disk with little material (e.g. Hernández et al. 2007).”
• On the diversity and statistical properties of protostellar discs (2018, background): “…the youngest star-forming regions (a few Myr), observational determinations of disc fractions typically range from ≈ 50 − 85% (Haisch et al. 2000; Lada et al. 2000; Haisch et al. 2001; Lada et al. 2006; Balog et al. 2007; Guarcello et al. 2007; Hernández et al. 2007,?, 2008; Harvey et al. 2008).”
• The Birth Environment of the Solar System (2010, background): “Since the timescale for giant planet formation (Lissauer & Stevenson 2007) and the expected lifetimes of circumstellar disks (Hernández et al. 2007) are both about 10 Myr, this constraint applies over the first ∼ 10 Myr of Solar System history.”
• Accretion disks in luminous young stellar objects (2015, background): “They are found around young stars associated with molecular clouds at a high incidence rate (Hernández et al., 2007).”
• TWO WIDE PLANETARY-MASS COMPANIONS TO SOLAR-TYPE STARS IN UPPER SCORPIUS (2010, background): “Their orbital radii are so large that the core accretion timescale (>100 Myr at 100 AU; Pollack et al. 1996) should be much longer than the typical protoplanetary disk dissipation timescale (∼3-5 Myr; Haisch et al. 2001; Hernández et al. 2007; Currie et al. 2009).”
• STRUCTURE AND EVOLUTION OF PRE-MAIN-SEQUENCE CIRCUMSTELLAR DISKS (2009, background): “Spatially unresolved observations of the infrared and mm-wave emission from nearby premain sequence stars surrounded by disks suggest that most of the circumstellar dust dissipates on timescales between 1 and 10 Myr (see, e.g., Hernández et al. 2007).”
• ALMA OBSERVATIONS OF CIRCUMSTELLAR DISKS IN THE UPPER SCORPIUS OB ASSOCIATION (2016, background): “…Carpenter et al. 2006; Lada et al. 2006; Sicilia-Aguilar et al. 2006; Balog et al. 2007; Barrado y Navascués et al. 2007; Cieza & Baliber 2007; Dahm & Hillenbrand 2007; Hernández et al. 2007a,b; Flaherty & Muzerolle 2008; Gutermuth et al. 2008; Hernández et al. 2008; Luhman & Mamajek 2012).”
• Ring shaped dust accumulation in transition disks (2012, background): “Decrease of mass accretion rate (Sicilia-Aguilar et al. 2010; Fedele et al. 2010), and near-infrared excess with time (Hernández et al. 2007; Andrews et al. 2011b) indicate that disks have a range of lifetimes from 1 to 10 Myr.”
• Dust Evolution and the Formation of Planetesimals (2016, background): “…in disks around different types of young stars from intermediate mass stars to brown dwarfs (Apai et al. 2005; Furlan et al. 2006; Sicilia-Aguilar et al. 2006; Balog et al. 2007; Hernández et al. 2007; Guarcello et al. 2009; Sicilia-Aguilar et al. 2011; Kraus et al. 2012; Fang et al. 2012, 2013).”
• ALMA SURVEY OF LUPUS PROTOPLANETARY DISKS. I. DUST AND GAS MASSES (2016, background): “Surveys of the optically thick infrared (IR) emission across young stellar clusters have constrained the disk dispersal timescale to ∼10 Myr, providing important checks on planet formation theories (Haisch et al. 2001; Hernández et al. 2007; Evans et al. 2009).”
• An ALMA Survey of Protoplanetary Disks in the σ Orionis Cluster (2017, methodology): “Only one-third of cluster members (92 sources) exhibit strong infrared (IR) excess indicative of a protoplanetary disk (Hernández et al. 2007).”
• The Evaporation Valley in the Kepler Planets (2017, methodology): “The Integration Starting from an initial envelope mass fraction at time zero, which we set to be 1 Myr (roughly the disk dispersal timescale, e.g. Hernández et al. 2007), we evolve the envelope mass fraction according to: dX dt = −X tẊ .”
• Protoplanetary disk lifetimes vs stellar mass and possible implications for giant planet populations (2015, result): “These results are in agreement with previous studies (e.g. Lada et al. 2000; Hernández et al. 2007b, 2008; Murphy et al. 2013) and supersede our results in R14.”
• NEW DEBRIS DISKS AROUND YOUNG, LOW-MASS STARS DISCOVERED WITH THE SPITZER SPACE TELESCOPE (2009, neutral): “…2009; Cieza et al. 2008; Currie et al. 2008b; Hernandez et al. 2008; Cieza & Baliber 2007; – 3 – Currie et al. 2007; Dahm & Hillenbrand 2007; Gorlova et al. 2007; Hernandez et al. 2007a,b; Carpenter et al. 2006; Chen et al. 2005b; Low et al. 2005; Stauffer et al. 2005; Gorlova et al. 2004).”
• Timescale of mass accretion in pre-main-sequence stars (2009, background): “…of an excess source is based on the slope (α) of the infrared spectral energy distribution determined from the IRAC [3.6] – [8.0] bands (Lada et al. 2006): αIRAC = d(log(λFλ)) d(log(λ)) ; 3.6µm< λ < 8.0µm (2) Stars with −1.8 < α < 0 are classified as class II (e.g. Hernández et al. 2007).”
• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster (2007, background): “It has been demonstrated previously that the fraction of cluster members with disks roughly traces the mean age of the pre-main sequence cluster members (e.g. Haisch et al. 2001; Hernandez et al. 2007).”