Warm Debris Disk Candidates around Nearby FGK Stars from LAMOST DR12

Abstract

Warm debris disks around main-sequence stars trace late-stage terrestrial planet formation. Motivated by the need for systematic searches of such systems, we identify debris disk candidates around FGK stars within 150 pc by combining a spectroscopically selected sample from LAMOST DR12 with Gaia astrometry and multi-band infrared photometry. Infrared excesses are identified through SED fitting and validated using conservative, source-by-source checks. This approach yields a final sample of 12 debris disk candidates including ten new detections. Stellar age research indicate that most of the host stars are several billion years old. NEOWISE monitoring reveals no significant W1/W2 variability, consistent with a circumstellar origin of the infrared excess. while a search for co-moving companions using Gaia DR3 reveals possible companions for only two candidates at very large projected separations ($\gtrsim 10^4$~au). Three candidates exhibit excess emission in both the W3 and W4 bands, allowing estimates of characteristic dust properties. This work establishes a small yet reliable sample of debris disk candidates anchored in homogeneous LAMOST spectroscopy, providing a foundation for future studies of debris disk evolution and stellar activity.

Figures (12)

• Figure 1: Distribution of the $\sim$23 000 sources after a sequential selection process, with colors indicating excluded objects and the dashed line denoting the white dwarf removal criterion.
• Figure 2: The relationship between the Gaia FoM and the signal-to-noise ratio (S/N) in the AllWISE W1 band for the 12 debris-disk candidates, with the color scale showing the positional offset between the Gaia and AllWISE positions.
• Figure 3: Sample Selection and Screening Process
• Figure 4: For the fitting, all targets use photometric data from Gaia DR3, 2MASS, and AllWISE, except for J011938.78+191543.8, for which additional optical data from SDSS were included.
• Figure 5: The left panel shows the variability indices and thresholds for J022959.14+362405.6. The green dashed line represents the variability threshold, and the arrow indicates the position of the target source. The right panel shows the seasonal averages of W1 and W2 fluxes for the sample, with blue circles and red triangles representing W1 and W2, respectively. Error bars indicate the uncertainties of the seasonal averages. Purple squares show the W1/W2 flux ratio and its associated uncertainties.