Infrared L-Band Observations of the Trapezium Cluster: A Census of Circumstellar Disks and Candidate Protostars

By C. Lada, August Muench, K. Haisch, E. Lada, Joao F. Alves, E. Tollestrup, S. Willner. 2000

176 citations recorded by the source corpus.

We report the results of a sensitive near-infrared JHKL imaging survey of the Trapezium cluster in Orion. We use the JHKL colors to obtain a census of infrared excess stars in the cluster. Of (391) stars brighter than 12th magnitude in the K and L bands, 80% ± 7% are found to exhibit detectable infrared excess on the J-H, K-L color-color diagram. Examination of a subsample of 285 of these stars with published spectral types yields a slightly higher infrared excess fraction of 85%. We find that 97% of the optical proplyds in the cluster exhibit excess in the JHKL color-color diagram indicating that the most likely origin of the observed infrared excesses is from circumstellar disks. We interpret these results to indicate that the fraction of stars in the cluster with circumstellar disks is between 80%–85%, confirming earlier published suggestions of a high disk fraction for this young cluster. Moreover, we find that the probability of finding an infrared excess around a star is independent of stellar mass over essentially the entire range of the stellar mass function down to the hydrogen burning limit. Consequently, the vast majority of stars in the Trapezium cluster appear to have been born with circumstellar disks and the potential to subsequently form planetary systems, despite formation within the environment of a rich and dense stellar cluster. We identify 78 stars in our sample characterized by K-L colors suggestive of deeply embedded objects. The spatial distribution of these objects differs from that of the rest of the cluster members and is similar to that of the dense molecular cloud ridge behind the cluster. About half of these objects are detected in the short wavelength (J and H) bands, and these are found to be characterized by extreme infrared excess. This suggests that many of these sources could be protostellar in nature. If even a modest fraction (i.e., ∼50%) of these objects are protostars, then star formation could be continuing in the molecular ridge at a rate comparable to that which produced the foreground Trapezium cluster.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/3d3bea7d521b6064bb1f7a349819db4ea86dc58a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

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

In Atmospheric Science

1. K. Luhman
2. F. Allard
3. Peter Hauschildt
4. L. Hillenbrand
5. C. Lada
6. P. Lucas
7. P. Roche
8. Eric Mamajek

In Spectroscopy

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

Citations in the corpus

• The Spectroscopically Determined Substellar Mass Function of the Orion Nebula Cluster (2004, background): “It has been shown (see Hillenbrand et al. 1998, Lada et al. 2000, and Muench et al. 2001) that ∼50% of sources in the ONC show signs of (J − H),(H − K) infrared excess consistent with emission from a circumstellar disk.”
• The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics Observations (2007, background): “Based on the JHKL observations of the Trapezium cluster, Lada et al. (2000) report that they find a considerably lower disk fraction for the high-mass O, B, and A stars than that for F-M type stars, and this could be due to either a lower probability for disk formation or more rapid disk dispersal…”
• Protoplanetary disk lifetimes vs stellar mass and possible implications for giant planet populations (2015, background): “For these reasons, we tentatively estimate uncertainties on the disk fractions by performing bootstrapping (1000 iterations) A52, page 5 of 13 randomly varying the Teff , photometric fluxes, the young/old boundary, the high mass/low mass boundary, and the object distances within normal distributions”
• Herschel-Planck dust optical-depth and column-density maps - I. Method description and results for Orion (2014, unknown): “It contains the nearest massive star-forming cluster to Earth, the Trapezium cluster (e.g. Hillenbrand 1997; Lada et al. 2000; Muench et al. 2002; Da Rio et al. 2012), at a distance of 414 pc Menten et al. 2007).”
• A Spitzer Census of the IC 348 Nebula (2007, methodology): “The fact that protostellar populations are often observed to be aligned in filamentary structures, including, for examples, the Spokes cluster in NGC 2264 and the embedded subclusters behind the Trapezium in Orion, lends support to this hypothesis.”
• A 3-5 mu m VLT spectroscopic survey of embedded young low mass stars I - Structure of the CO ice (2003, background): “Orion TPSC 1 and TPSC 78 are two extremely red sources located in the trapezium cluster within 2′of the BN/KL region, with K−L > 6.1 and 4.85, respectively Lada et al. (2000).”
• Disk Evolution in Cep OB2: Results from the Spitzer Space Telescope (2006, background): “…a strong decline in the frequency of these disk signatures between 1 and 10 Myr (Strom et al. 1989; Skrutskie et al. 1990; Hillenbrand et al. 1998; Lada et al. 2000;Muzerolle et al. 2000; Haisch et al. 2001; Briceño et al. 2001; Sicilia-Aguilar et al. 2005b, hereafter Paper II; Calvet et al.…”
• On the diversity and statistical properties of protostellar discs (2018, background): “For 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.…”
• X-Ray-emitting Young Stars in the Orion Nebula (2002, background): “…images (Bally et al. 1998; Bally, O’Dell, & McCaughrean 2000; Bally & Reipurth 2001); L, L-band (3.5 lm) excess interpreted as protostellar candidate (Lada et al. 2000); N, N-band (10 lm) excess interpreted as truncated disk (Stassun et al. 2001); pd, proplyd and/or disk imaged by theHST in…”
• THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. I. A CENSUS OF DUSTY YOUNG STELLAR OBJECTS AND A STUDY OF THEIR MID-INFRARED VARIABILITY (2012, background): “…initial mass function (Hillenbrand 1997; Luhman et al. 2000; Muench et al. 2002), the evolution of disks around young stars (Hillenbrand et al. 1998; Lada et al. 2000, 2004), and the structure and kinematics of young clusters (Hillenbrand & Hartmann 1998; Fűrész et al. 2008; Tobin et al. 2009).”
• The Luminosity and Mass Function of the Trapezium Cluster: From B Stars to the Deuterium-burning Limit (2002, methodology): “Subsets of this catalog have been previously used in the Lada et al. (2000) andMuench et al. (2001) studies of the frequency of circumstellar disks around stars and brown dwarfs in the Trapezium cluster.”
• The formation of a star cluster: predicting the properties of stars and brown dwarfs (2002, background): “We know from infrared excesses that most of the stars and brown dwarfs in the Trapezium Cluster have discs (Hillenbrand et al. 1998; Lada et al. 2000).”
• Photoevaporation of Circumstellar Disks around Young Stars (2004, background): “Observational evidence for circumstellar disks takes many forms, from direct imaging (e.g., Jayawardhana et al. 2002) and imaging of disk silhouettes (e.g., Bally, O’Dell, & McCaughrean 2000) through indirect measurements such as infrared excess (e.g., Lada et al. 2000).”
• Infrared Array Camera (IRAC) Colors of Young Stellar Objects (2004, background): “They, along with others (Lada et al. 2000) also showed that the K-L color index is a more effective measure of near-IR excess than H-K and is better for distinguishing Class I from Class II sources.”
• Observational Constraints on the Formation and Evolution of Binary Stars (2001, background): “Deep NIR surveys, ideally including L-band measurements, offer the best hope of identifying these peculiar young stars (e.g., Haisch et al. 2000; Lada et al. 2000).”
• Evidence for Mass-dependent Circumstellar Disk Evolution in the 5 Myr Old Upper Scorpius OB Association (2006, background): “However, Hernández et al. (2006) found that 7 of 11 F-stars in Orion OBIb contain 24µm excesses consistent with a debris disk, suggesting that the excess fraction for F and G-stars in Upper Sco may increase once our longer wavelength observations are obtained.”
• The Disk Population of the Chamaeleon I Star-forming Region (2008, background): “…find that they are highly clustered and are concentrated near dense molecular gas, which are typical properties of class I objects in embedded clusters (Hartmann 2002; Lada et al. 2000, 2004; Teixeira et al. 2006; Muench et al. 2007; Allen et al. 2007; Gutermuth et al. 2007; Winston et al. 2007).”