Low-mass stars and brown dwarfs

My science interests focus on low-mass stars and brown dwarfs. I am particularly interested in brown dwarf atmospheres, physical properties, and using brown dwarfs to understand both star and planet formation.

Infrared Spectroscopy

surface gravity examples in L dwarfs
J-band spectra of three L3 type brown dwarfs with low, intermediate, and high gravity. The potassium and iron hydride absorption features are used to trace surface gravity in brown dwarf atmospheres.

I studied surface gravities of brown dwarfs using gravity-sensitive features in the J-band spectra of brown dwarfs. I measured neutral potassium and iron hydride absorption to characterize surface gravity, in order to disentangle the effects of mass, temperature, and age on these brown dwarf spectra. Our paper was recently published in the Astrophysical Journal, and on the arxiv: Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey


(Left) Astrometric measurements of a Y dwarf, WISE 0410+1502. (Right) Parallactic ellipse, after the proper motion component has been removed.

I recently published a paper in which we measured distances to the coldest brown dwarfs in the Solar Neighborhood. We use Spitzer IRAC channel 2 images over baselines of >2 years to measure the motions of these cool objects. Having precise distances allowed us to measure the absolute magnitudes and infer information about the temperatures of these cold, nearby objects.




Refereed Publications:

C. E. Hood, J. J. Fortney, M. R. Line, E. C. Martin, C. V. Morley, J. L. Birkby, Z. Rustamkulov, R. E. Lupu, R. S. Freedman, “Prospects for Characterizing the Haziest Sub-Neptune Exoplanets with High Resolution Spectroscopy.”, 2020 AJ, in press, arxiv:

M.-G. Suh, X. Yi, Y.-H. Lai, S. Leifer, I. S. Grudinin, G. Vasisht, E. C. Martin, M. P. Fitzgerald, G. Doppmann, J. Wang, D. Mawet, S. B. Papp, S. A. Diddams, C. A. Beichman, K. Vahala, “Searching for Exoplanets Using a Microresonator Astrocomb.”, 2019, Nature Photonics, 13, 25-30. doi: 10.1038/s41566-018-0312-3

J. D. Kirkpatrick, E. C. Martin, R. L. Smart, et al., “Preliminary Trigonometric Parallaxes of 184 Late-T and Y Dwarfs and an Analysis of the Field Substellar Mass Function into the “Planetary” Mass Regime.”, 2019, ApJS, 240, 19, doi: 10.3847/1538-4365/aaf6af

E. C. Martin, J. D. Kirkpatrick, C. A. Beichman, R. L. Smart, J. K. Faherty, C. R. Gelino, M. C. Cushing, A. C. Schneider, E. L. Wright, P. J. Lowrance, J. Ingalls, C. G. Tinney, I. S. McLean, S. E. Logsdon, J. Lebreton. “Y Dwarf Trigonometric Parallaxes from the Spitzer Space Telescope.”, 2018, ApJ 867, 109, doi: 10.3847/1538-4357/aae1af

S. E. Logsdon, G. N. Mace, I. S. McLean, E. C. Martin. “Probing Late-type T dwarf J – H Color Outliers for Signs of Age.”, 2018, ApJ, 867, 96, doi: 10.3847/1538-4357/aade9b

E.C. Martin, G. N. Mace, I. S. McLean, et al., Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey, 2017, ApJ, 838, 73, doi:10.3847/1538-4357/aa6338

J.D. Kirkpatrick, K. Kellogg, A. C. Schneider, et al. (including E. C. Martin), The AllWISE Motion Survey, Part 2, 2016, ApJS, 224, 36, doi:10.3847/0067-0049/224/2/36

X. Yi, K. Vahala, J. Li, et al. (including E. C. Martin), Demonstration of a Near-IR Line-Referenced Electro-Optical Laser Frequency Comb for Precision Radial Velocity Measurements in Astronomy, 2016, Nature Communications, 7, 10436, doi:10.1038/ncomms10436

SPIE Publications:

E. C. Martin, M.P. Fitzgerald, I. S. McLean, et al., Overview of the NIRSPEC upgrade for the Keck II telescope, 2018, Proc. SPIE, arxiv:

E. C. Martin, M.P. Fitzgerald, I. S. McLean, et al., Optical design of the slit-viewing camera for the NIRSPEC upgrade, 2016, Proc. SPIE, 9908, 2R, doi:10.1117/12.2233767

E.C.Martin, M.P. Fitzgerald, I. S. McLean, et al., Performance modeling of an upgraded NIRSPEC on Keck, 2014, Proc. SPIE, 9147, 81, doi:10.1117/12.2056896

J. L. Marshall, D. L. DePoy, T. Prochaska, et al. (including E. C. Martin), VIRUS Instrument Collimator Assembly, 2014, Proc. SPIE, 9147, 3S, doi:10.1117/12.2056757

T. Prochaska, R.D. Allen, E. Boster, et al. (including E. C. Martin), VIRUS spectrograph assembly and alignment procedures, 2012, Proc. SPIE, 8446, 51, doi:10.1117/12.925487

E.C. Martin, D. L. DePoy, J.L. Marshall, Optical design of a red-sensitive spectrograph, 2012, Proc. SPIE, 8446, 2U, doi:10.1117/12.926281

J.P. Rheault, D.L. DePoy, J.L. Marshall, et al. (including E. C. Martin), Spectrophotometric calibration system for DECam, 2012, Proc. SPIE, 8446, 6M, doi:10.1117/12.924774