Hubble Cycle 18 Proposal Selection

Science Program

The TAC and the panels recommended a broad range of science categories, from nearby, solar-system objects to galaxies at redshifts of z ~ 8, and utilizing the power of all Hubble instruments.

One TAC-approved program aims to collect STIS ultraviolet echelle spectra for a diverse sample of cool stars, to build an advanced spectral library for astrophysical exploration. This library will allow the detection of rare species in sharp-lined F stars, properties and kinematics of local interstellar clouds, and the dynamics of chromospheres, coronae, and winds of cool stars.  Rapid public release of the data will enable many other investigations by a much wider community, no doubt continuing for decades to come.

An approved Hubble exoplanet program is scientifically complementary to Spitzer, Kepler, and COROT (Convection, ROtation and planetary Transits) results. The PI and CoIs will obtain transmission spectroscopy of the 1.4-micron water band in a sample of 13 planets, using the G141 grism of WFC3.  Among the abundant molecules, only water absorbs at this wavelength, and a measurement of water abundance will remove ambiguities in the Spitzer results.

IGM science is represented by new COS G130M and G160M observations of quasi-stellar objects, which will probe the gaseous halos of dwarf galaxies well inside their virial radii. Using sensitive absorption-line measurements, the program will map the halos of low-luminosity galaxies over impact parameter to distances of 15−150 kpc. These observations will directly constrain the content and kinematics of accreting and outflowing material and will be highly relevant to the study of galaxies at high z, where shallow halo are the norm.

Submitted/Approved Orbits by Science Category


A 250-orbit program will provide rest-frame optical spectra for a complete sample of 9,000 galaxies at redshifts 1 < z < 3.5. It was during this period that most star formation took place, the number density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in galaxies today must have emerged. The survey area will cover a subset of the fields included in the CANDELS Multi-Cycle Treasury program, amplifying the scientific returns from that program.