to be a brown dwarf of spectral class L2 that is only 8% as massive as the Sun. Normally a faint object dimmer than magnitude 15, it flared up in 1913, 1946 and 1978 to be visible in binoculars. The black widow pulsar (B1957+20) is the second millisecond pulsar ever discovered. It is a massive neutron star that is ablating its brown dwarf-sized companion which causes the pulsar's radio signals to attenuate as they pass through the outflowing material. Stars with exoplanets HD 231701 is a yellow-white main sequence star hotter and larger than our Sun, with a Jupiter-like planet that was discovered in 2007 by the radial velocity technique. The planet orbits at a distance of from the star with a period of 141.6 days. It has a mass of at least 1.13 Jupiter masses. HAT-P-34 is a star times as massive as the Sun with times its radius and times its luminosity. With an apparent magnitude of 10.4, it is distant. A planet times as massive as Jupiter was discovered transiting it in 2012. With a period of 5.45 days and a distance of from its star, it has an estimated surface temperature of . 15 Sagittae is a solar analog—a star similar to the Sun, with times its mass, times its radius and times its luminosity. It has an apparent magnitude of 5.80. It has an L4 brown dwarf substellar companion that is around the same size as Jupiter but 69 times as massive with a surface temperature of between 1,510 and , taking around 73.3 years to complete an orbit around the star. The system is estimated to be billion years old. Deep-sky objects The band of the Milky Way and the Great Rift within it pass though Sagitta, with Alpha, Beta and Epsilon Sagittae marking the Rift's border. Located between Beta and Gamma Sagittae is Messier 71, a very loose globular cluster mistaken for some time for a dense open cluster. At a distance of about from Earth, it was first discovered by the French astronomer Philippe Loys de Chéseaux in the year 1745 or 1746. The loose globular cluster has a mass of around and a luminosity of approximately 19,000 . There are two notable planetary nebulae in Sagitta: NGC 6886 is composed of a hot central post-AGB star that has 55% of the Sun's mass yet times its luminosity, with a surface temperature