The Solar Neighborhood targets a volume-limited sample of stars with the goals of cataloging low-luminosity stellar populations. These will be the brightest of each type, and we will be able to determine accurate stellar parameters from the combination of spectroscopy, photometry, and parallaxes. In addition, we will be able to get very good constraints on binarity from the combination of radial velocity (RV) spectroscopy and Gaia astrometry. The most complete census will be within 100 pc. However, few stars within 100 pc have spectral types earlier than K; therefore, a sample of G-type stars and earlier within 250 pc will also be targeted to enable a reliable match to higher luminosity populations.
The Gaia DR2 parallaxes are noticeably less accurate in highly crowded regions. Therefore, stars close to the Galactic plane and the Magellanic Clouds have an additional quality cut on astrometric noise imposed.
Cartons
mwm_snc_100pc
This carton is the 100 pc sample observed during the plate era from targeting plan 0.1.0. In DR19, all cartons in this program also belong to the alternate name mwm_snc.
The selection criteria utilized astrometric information from Gaia DR2 and photometry from both Gaia DR2 or 2MASS. Dense regions were defined with the Galactic longitude b and Galactic latitude l in degrees as follows:
- Galactic Plane:
- l<=180 and b<-0.139*l + 25 and b>0.139*l-25 OR
- l>180 and b>-0.139*l + 25 and b <0.139*l – 25
- SMC: sqrt( (l-303.2)2 + 2*(b+44.4)2 ) < 5
- LMC: sqrt( (l-280.3)2 + 2*(b+33.0)2 ) < 8
Selection Criteria
- parallax-parallax_error > 10 mas
- if in dense region, astrometric_excess_noise < 2
mwm_snc_100pc_apogee
This carton is the FPS era 100 pc sample observed with the APOGEE instrument under targeting plan 0.5.0. In addition to the selection criteria of mwm_snc_100pc, this carton required H < 11.
mwm_snc_100pc_boss
This carton is the FPS era 100 pc sample observed with the BOSS instrument under targeting plan 0.5.0. In addition to the selection criteria of mwm_snc_100pc, this carton also required G-band detection in Gaia.
mwm_snc_250pc
This carton is the 250 pc sample observed during the plate era from targeting plan 0.1.0. To observe stars of type G and earlier, we limit the absolute magnitude MG< 6.
Selection Criteria
- parallax – parallax_error > 4
- if in dense region, astrometric_excess_noise < 2
- G+5 * log10(parallax / 1000) + 5 < 6
mwm_snc_250pc_apogee
This carton is the FPS era 250 pc sample observed with the APOGEE instrument under targeting plan 0.5.0. In addition to the selection criteria of mwm_snc_250pc, this carton required H < 11.
mwm_snc_250pc_boss
This carton is the FPS era 250 pc sample observed with the BOSS instrument under targeting plan 0.5.0 and uses the same selection criteria as mwm_snc_250pc.
Cadences
During plate observations, targets could be observed with either the BOSS or APOGEE instrument. APOGEE observations were allowed on plates with any cadence, while BOSS observations were allowed on all plates except those with the RM cadence.
During FPS operations, all targets in the *_apogee cartons utilized the bright_1x1 cadence, while targets in the *_boss cartons utilized either the bright_2x1 (for G < 16) or dark_2x1 (for G > 16) cadences.