We report the discovery of an eclipsing binary -- PTF1 J072456$+$125301-- composed of a subdwarf B (sdB) star ($g=17.2^m$) with a faint companion. Subdwarf B stars are core helium-burning stars, which can be found on the extreme horizontal branch. Ab
out half of them reside in close binary systems, but few are known to be eclipsing, for which fundamental stellar parameters can be derived. ewline We conducted an analysis of photometric data and spectra from the Palomar 60 and the 200 Hale telescope respectively. A quantitative spectral analysis found an effective temperature of $T_{text{eff}}=33900pm350$,K, log g = $5.74pm0.08$ and log($n_{text{He}}/n_{text{H}}) = -2.02 pm0.07$, typical for an sdB star. The companion does not contribute to the optical light of the system, except through a distinct reflection effect. From the light curve an orbital period of 0.09980(25),d and a system inclination of $83.56pm0.30,^{circ}$ were derived. The radial velocity curve yielded an orbital semi-amplitude of $K_1=95.8pm 8.1,text{km s$^{-1}$}$. The mass for the M-type dwarf companion is $0.155pm0.020,M_{odot}$. PTF1,J072456$+$125301 has similar atmospheric parameters to those of pulsating sdB stars (V346 Hya stars). Therefore it could be a high-priority object for asteroseismology, if pulsations were detected such as in the enigmatic case of NY Vir.
We report the discovery of two new halo velocity groups (Cancer groups A and B) traced by 8 distant RR Lyrae stars and observed by the Palomar Transient Factory (PTF) survey at R.A.~129 deg, Dec~20 deg (l~205 deg, b~32 deg). Located at 92 kpc from th
e Galactic center (86 kpc from the Sun), these are some of the most distant substructures in the Galactic halo known to date. Follow-up spectroscopic observations with the Palomar Observatory 5.1-m Hale telescope and W. M. Keck Observatory 10-m Keck I telescope indicate that the two groups are moving away from the Galaxy at v_{gsr} = 78.0+-5.6 km/s (Cancer group A) and v_{gsr} = 16.3+-7.1 km/s (Cancer group B). The groups have velocity dispersions of sigma_{v_{gsr}}=12.4+-5.0 km/s and sigma_{v_{gsr}}=14.9+-6.2 km/s, and are spatially extended (about several kpc) making it very unlikely that they are bound systems, and are more likely to be debris of tidally disrupted dwarf galaxies or globular clusters. Both groups are metal-poor (median metallicities of [Fe/H] = -1.6 dex and [Fe/H] =-2.1 dex), and have a somewhat uncertain (due to small sample size) metallicity dispersion of ~0.4 dex, suggesting dwarf galaxies as progenitors. Two additional RR Lyrae stars with velocities consistent with those of the Cancer groups have been observed ~25 deg east, suggesting possible extension of the groups in that direction.
