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DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. II. EXTRAGALACTIC DISKS OR EXAMPLES OF THE PLEIADES PHENOMENON? (2013)
Journal Article
Adams, J. J., Simon, J. D., Bolatto, A. D., Sloan, G. C., Sandstrom, K. M., Schmiedeke, A., …Keller, L. D. (2013). DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. II. EXTRAGALACTIC DISKS OR EXAMPLES OF THE PLEIADES PHENOMENON?. Astrophysical Journal, 771(2), Article ARTN 112. https://doi.org/10.1088/0004-637x/771/2/112

We use mid-infrared Spitzer spectroscopy and far-infrared Herschel photometry for a sample of 20 main sequence O9–B2 stars in the Small Magellanic Cloud (SMC) with strong 24 μm excesses to investigate the origin of the mid-IR emission. Either debris... Read More about DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. II. EXTRAGALACTIC DISKS OR EXAMPLES OF THE PLEIADES PHENOMENON?.

DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. I. OPTICAL SPECTROSCOPY REVEALS PREDOMINANTLY MAIN-SEQUENCE OB STARS (2013)
Journal Article
Sheets, H. A., Bolatto, A. D., van Loon, J. T., Sandstrom, K., Simon, J. D., Oliveira, J. M., & Barbá, R. H. (in press). DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. I. OPTICAL SPECTROSCOPY REVEALS PREDOMINANTLY MAIN-SEQUENCE OB STARS. Astrophysical Journal, 771(2), Article 111. https://doi.org/10.1088/0004-637x/771/2/111

We present the results of optical spectroscopic follow-up of 125 candidate main sequence OB stars in the Small Magellanic Cloud (SMC) that were originally identified in the S3MC infrared imaging survey as showing an excess of emission at 24 μm indica... Read More about DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. I. OPTICAL SPECTROSCOPY REVEALS PREDOMINANTLY MAIN-SEQUENCE OB STARS.

AN X-RAY SURVEY OF THE YOUNG STELLAR POPULATION OF THE LYNDS 1641 AND IOTA ORIONIS REGIONS (2013)
Journal Article
Pillitteri, I., Wolk, S. J., Megeath, S. T., Allen, L., Bally, J., Gagné, M., …Stauffer, J. (in press). AN X-RAY SURVEY OF THE YOUNG STELLAR POPULATION OF THE LYNDS 1641 AND IOTA ORIONIS REGIONS. Astrophysical Journal, 768(2), 99. https://doi.org/10.1088/0004-637x/768/2/99

We present an XMM-Newton survey of the part of the Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux,... Read More about AN X-RAY SURVEY OF THE YOUNG STELLAR POPULATION OF THE LYNDS 1641 AND IOTA ORIONIS REGIONS.

Early-stage young stellar objects in the Small Magellanic Cloud (2012)
Journal Article
Oliveira, J., Th. van Loon, J., Sloan, G., Sewiło, M., Kraemer, K., Wood, P., …Simon, J. (2013). Early-stage young stellar objects in the Small Magellanic Cloud. Monthly Notices of the Royal Astronomical Society, 428(4), 3001-3033. https://doi.org/10.1093/mnras/sts250

We present new observations of 34 YSO candidates in the SMC. The anchor of the analysis is a set of Spitzer-IRS spectra, supplemented by groundbased 3-5 micron spectra, Spitzer and NIR photometry, optical spectroscopy and radio data. The sources' SED... Read More about Early-stage young stellar objects in the Small Magellanic Cloud.

Ice chemistry in massive Young Stellar Objects: the role of metallicity (2011)
Journal Article
Oliveira, J., van Loon, J., Sloan, G., Indebetouw, R., Kemper, F., Tielens, A. G. M., …Meixner, M. (2011). Ice chemistry in massive Young Stellar Objects: the role of metallicity. Monthly Notices of the Royal Astronomical Society: Letters, 411(1), L36–L40. https://doi.org/10.1111/j.1745-3933.2010.00990.x

We present the comparison of the three most important ice constituents (water, CO and CO2) in the envelopes of massive Young Stellar Objects (YSOs), in environments of different metallicities: the Galaxy, the Large Magellanic Cloud (LMC) and, for the... Read More about Ice chemistry in massive Young Stellar Objects: the role of metallicity.

Ice chemistry in embedded young stellar objects in the Large Magellanic Cloud (2009)
Journal Article
Oliveira, J. M., van Loon, J. T., Chen, C. R., Tielens, A. G. G. M., Sloan, G. C., Woods, P. M., …Marengo, M. (2009). Ice chemistry in embedded young stellar objects in the Large Magellanic Cloud. Astrophysical Journal, 707(1269), https://doi.org/10.1088/0004-637X/707/2/1269

We present spectroscopic observations of a sample of 15 embedded young stellar objects (YSOs) in the Large Magellanic Cloud (LMC). These observations were obtained with the Spitzer Infrared Spectrograph (IRS) as part of the SAGE-Spec Legacy program.... Read More about Ice chemistry in embedded young stellar objects in the Large Magellanic Cloud.

The star formation process in the Magellanic Clouds (2008)
Journal Article
M. Oliveira, J. (2008). The star formation process in the Magellanic Clouds. Proceedings of the International Astronomical Union, https://doi.org/10.1017/S1743921308028457

The Magellanic Clouds offer unique opportunities to study star formation both on the global scales of an interacting system of gas-rich galaxies, as well as on the scales of individual star-forming clouds. The interstellar media of the Small and Larg... Read More about The star formation process in the Magellanic Clouds.

The Keele–Exeter young cluster survey – I. Low-mass pre-main-sequence stars in NGC 2169 (2007)
Journal Article
Jeffries, R., Oliveira, J., Naylor, T., Mayne, N., & Littlefair, S. (2007). The Keele–Exeter young cluster survey – I. Low-mass pre-main-sequence stars in NGC 2169. Monthly Notices of the Royal Astronomical Society, 376(2), 580 -598. https://doi.org/10.1111/j.1365-2966.2007.11327.x

We have used R_C I_C CCD photometry from the Isaac Newton telescope and intermediate resolution spectroscopy from the Gemini North telescope to identify and characterise low-mass (0.15

Kinematic structure in the young σ Orionis association (2006)
Journal Article
Jeffries, R., Maxted, P., Oliveira, J., & Naylor, T. (2006). Kinematic structure in the young σ Orionis association. Monthly Notices of the Royal Astronomical Society, 371(1), L6 - L10. https://doi.org/10.1111/j.1745-3933.2006.00196.x

We have used precise radial velocity measurements for a large number of candidate low-mass stars and brown dwarfs, to show that the young Sigma Ori ``cluster'' consists of two spatially superimposed components which are kinematically separated by 7 k... Read More about Kinematic structure in the young σ Orionis association.

Star Formation in the Eagle Nebula and NGC 6611 (2006)
Journal Article
Oliveira, J. M., Jeffries, R. D., & van Loon, J. T. (2006). Star Formation in the Eagle Nebula and NGC 6611. Proceedings of the International Astronomical Union, 2(S237), https://doi.org/10.1017/S1743921307002487

We present IZJHKL' photometry of the core of the cluster NGC 6611 in the Eagle Nebula. This photometry is used to constrain the Initial Mass Function (IMF) and the circumstellar disk frequency of the young stellar objects. Optical spectroscopy of 258... Read More about Star Formation in the Eagle Nebula and NGC 6611.

Circumstellar discs in the young σ Orionis cluster (2006)
Journal Article
Oliveira, J., Jeffries, R., Van Loon, J., & Rushton, M. (2006). Circumstellar discs in the young σ Orionis cluster. Monthly Notices of the Royal Astronomical Society, 369(1), 272 -280. https://doi.org/10.1111/j.1365-2966.2006.10299.x

We present new K- and L'-band imaging observations for members of the young (3-5 Myr) sigma Orionis cluster, obtained with UIST at UKIRT. We determine (K-L') colour excesses with respect to the photospheres, finding evidence for warm circumstellar du... Read More about Circumstellar discs in the young σ Orionis cluster.

The lithium depletion boundary in NGC 2547 as a test of pre-main-sequence evolutionary models (2005)
Journal Article
Jeffries, R. D., & Oliveira, J. M. (2005). The lithium depletion boundary in NGC 2547 as a test of pre-main-sequence evolutionary models. Monthly Notices of the Royal Astronomical Society, 358(1), 13 -29. https://doi.org/10.1111/j.1365-2966.2005.08820.x

Intermediate resolution spectroscopy from the ESO Very Large Telescope is analysed for 63 photometrically selected low-mass (0.08-0.30 Msun) candidates of the open cluster NGC 2547. We have confirmed membership for most of these stars using radial ve... Read More about The lithium depletion boundary in NGC 2547 as a test of pre-main-sequence evolutionary models.

Circumstellar discs around solar-mass stars in NGC 6611 (2005)
Journal Article
Oliveira, J., Jeffries, R., Th. van Loon, J., Littlefair, S., & Naylor, T. (2005). Circumstellar discs around solar-mass stars in NGC 6611. Monthly Notices of the Royal Astronomical Society: Letters, 358(1), L21-L24. https://doi.org/10.1111/j.1745-3933.2005.00020.x

We have performed IZJHKL' observations in NGC 6611, the young cluster that ionises the Eagle Nebula. We have discovered a rich pre-main sequence concentrated around the O-stars in the cluster. As measured by their L'-band excesses, at least 58% +/- 5... Read More about Circumstellar discs around solar-mass stars in NGC 6611.

Membership, binarity and accretion among very low-mass stars and brown dwarfs of the s Orionis cluster (2005)
Journal Article
Kenyon, M., Jeffries, R., Naylor, T., Oliveira, J., & Maxted, P. (2005). Membership, binarity and accretion among very low-mass stars and brown dwarfs of the s Orionis cluster. Monthly Notices of the Royal Astronomical Society, 356(1), 89 -106. https://doi.org/10.1111/j.1365-2966.2004.08455.x

Intermediate resolution (R=7000) spectroscopy is presented for 76 photometrically selected very low mass (0.04

Young stars and their circumstellar disks in the Sigma Orionis cluster (2004)
Conference Proceeding
M. Oliveira, J., D. Jeffries, R., Th. van Loon, J., & J. Kenyon, M. (2004). Young stars and their circumstellar disks in the Sigma Orionis cluster. In Open Issues in Local Star Formation (55–62). https://doi.org/10.1007/1-4020-2600-5_6

The sigma Orionis cluster is a young association evolving under the disruptive influence of its massive O-star namesake. We are analysing this cluster as part of a program to characterise the influence of O-stars on the early stages of stellar evolut... Read More about Young stars and their circumstellar disks in the Sigma Orionis cluster.

Mid-infrared observations of young stellar objects in the vicinity of sigma Orionis (2004)
Journal Article
Oliveira, J. M., & van Loon, J. T. (2004). Mid-infrared observations of young stellar objects in the vicinity of sigma Orionis. Astronomy & Astrophysics, 418(2), https://doi.org/10.1051/0004-6361%3A20034518

We present new mid-infrared observations of objects in the vicinity of the O-star sigma Orionis, obtained with TIMMI-2 at ESO. By constraining their near- and mid-infrared spectral energy distributions, we established the nature of previously known I... Read More about Mid-infrared observations of young stellar objects in the vicinity of sigma Orionis.

An L'-band survey for circumstellar discs around low-mass stars in the young σ Orionis cluster (2004)
Journal Article
Jeffries, R., Oliveira, J., & Van Loon, J. (2004). An L'-band survey for circumstellar discs around low-mass stars in the young σ Orionis cluster. Monthly Notices of the Royal Astronomical Society, 347(4), 1327 -1336. https://doi.org/10.1111/j.1365-2966.2004.07315.x

We present new K- and L'-band imaging of a representative sample of members of the young 3-5 Myr old sigma Orionis cluster. We identified objects with (K-L') excess by analysing colour-colour diagrams and comparing the observations with empirical mai... Read More about An L'-band survey for circumstellar discs around low-mass stars in the young σ Orionis cluster.

Cool stars in NGC 2547 and pre-main-sequence lithium depletion (2003)
Journal Article
Jeffries, R., Oliveira, J., Barrado y Navascués, D., & Stauffer, J. (2003). Cool stars in NGC 2547 and pre-main-sequence lithium depletion. Monthly Notices of the Royal Astronomical Society, 343(4), 1271-1284. https://doi.org/10.1046/j.1365-8711.2003.06768.x

We present the results of a spectroscopic survey of X-ray selected, low-mass candidate members of the young open cluster NGC 2547. Using a combination of photometry, spectroscopic indices and radial velocities we refine our candidate list and then us... Read More about Cool stars in NGC 2547 and pre-main-sequence lithium depletion.

The lithium depletion boundary and the age of NGC 2547 (2003)
Journal Article
Oliveira, J., Barrado y Navascues, D., Jeffries, R., Devey, C., Navascues, D., Naylor, T., …Totten, E. (2003). The lithium depletion boundary and the age of NGC 2547. Monthly Notices of the Royal Astronomical Society, 342(2), 651 -663. https://doi.org/10.1046/j.1365-8711.2003.06592.x

We present the results of a photometric and spectroscopic survey of cool M dwarf candidates in the young open cluster NGC 2547. Using the 2dF fiber spectrograph, we have searched for the luminosity at which lithium remains unburned in an attempt to c... Read More about The lithium depletion boundary and the age of NGC 2547.