Two white dwarfs in ultrashort binaries with detached, eclipsing, likely sub-stellar companions detected by K2
Using data from the extended Kepler mission in K2 Campaign 10, we identify two eclipsing
binaries containing white dwarfs with cool companions that have extremely short orbital
periods of only 71.2 min (SDSS J1205− 0242, aka EPIC 201283111) and 72.5 min (SDSS
J1231+ 0041, aka EPIC 248368963). Despite their short periods, both systems are detached
with small, low-mass companions, in one case a brown dwarf and in the other case either a
brown dwarf or a low-mass star. We present follow-up photometry and spectroscopy of both�…
binaries containing white dwarfs with cool companions that have extremely short orbital
periods of only 71.2 min (SDSS J1205− 0242, aka EPIC 201283111) and 72.5 min (SDSS
J1231+ 0041, aka EPIC 248368963). Despite their short periods, both systems are detached
with small, low-mass companions, in one case a brown dwarf and in the other case either a
brown dwarf or a low-mass star. We present follow-up photometry and spectroscopy of both�…
Emission lines in the atmosphere of the irradiated brown dwarf WD0137− 349B
ES Longstaff, SL Casewell, GA Wynn…�- Monthly Notices of�…, 2017 - academic.oup.com
We present new optical and near-infrared spectra of WD0137− 349; a close white dwarf–
brown dwarf non-interacting binary system with a period of≈ 114 min. We have confirmed
the presence of H α emission and discovered He, Na, Mg, Si, K, Ca, Ti and Fe emission lines
originating from the brown-dwarf atmosphere. This is the first brown-dwarf atmosphere to
have been observed to exhibit metal emission lines as a direct result of intense irradiation.
The equivalent widths of many of these lines show a significant difference between the day�…
brown dwarf non-interacting binary system with a period of≈ 114 min. We have confirmed
the presence of H α emission and discovered He, Na, Mg, Si, K, Ca, Ti and Fe emission lines
originating from the brown-dwarf atmosphere. This is the first brown-dwarf atmosphere to
have been observed to exhibit metal emission lines as a direct result of intense irradiation.
The equivalent widths of many of these lines show a significant difference between the day�…
The VLT LBG redshift survey – VI. Mapping H i in the proximity of z�∼�3 LBGs with X-Shooter
RM Bielby, T Shanks, NHM Crighton…�- Monthly Notices of�…, 2017 - academic.oup.com
We present an analysis of the spatial distribution and dynamics of neutral hydrogen gas
around galaxies using new X-Shooter observations of z∼ 2.5–4 quasars. Adding the X-
Shooter data to our existing data set of high-resolution quasar spectroscopy, we use a total
sample of 29 quasars alongside∼ 1700 Lyman Break Galaxies (LBGs) in the redshift range
2≲ z≲ 3.5. We measure the Lyα forest auto-correlation function, finding a clustering length of
s 0= 0.081�0.006 h− 1 Mpc, and the cross-correlation function with LBGs, finding a cross�…
around galaxies using new X-Shooter observations of z∼ 2.5–4 quasars. Adding the X-
Shooter data to our existing data set of high-resolution quasar spectroscopy, we use a total
sample of 29 quasars alongside∼ 1700 Lyman Break Galaxies (LBGs) in the redshift range
2≲ z≲ 3.5. We measure the Lyα forest auto-correlation function, finding a clustering length of
s 0= 0.081�0.006 h− 1 Mpc, and the cross-correlation function with LBGs, finding a cross�…