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gaia data release 3 documentation

10.8 Long period variables

10.8.1 Introduction

The Gaia DR3 provides the second Gaia all-sky catalogue of Long Period Variable (LPV) candidates. Compared to the first catalogue issued in Gaia DR2, this catalogue covers a longer duration of 34 months (22 months in Gaia DR2), with an increased mean number of observations per source of 43 (26 in Gaia DR2), includes sources with G variability amplitudes larger than 0.1 mag (0.2 mag in Gaia DR2), and contains about 1.7 million sources (151 761 sources in Gaia DR2), with one period determined for about 392 000 of them. A new feature compared to Gaia DR2 is the spectral class identification based on the RP spectra whenever possible (no spectral classification was performed in Gaia DR2). More precisely, a distinction is provided between cool giants of spectral types M (oxygen-rich) and C (carbon-rich). The list of LPV published attributes is contained in table vari_long_period_variable.

Some parameters provided in Gaia DR2 are no longer provided in the Gaia DR3 catalogue as they depend on interstellar extinction that was not yet available within the Gaia consortium at the time of LPV processing (we remind the reader that the corresponding values published in the Gaia DR2 catalogue of LPV candidates were not reliable for a similar reason). They can, however, easily be computed with the Gaia DR3 data products (including interstellar extinction), and the procedure is described in Mowlavi et al. (2018). These parameters are the bolometric correction (and its uncertainty), the absolute bolometric magnitude (and its uncertainty), and a flag indicating whether the source is a red supergiant.

The LPV selection criteria are described in Section 10.8.2. The processing steps leading to the LPV data products are summarized in Sections 10.8.3 and 10.8.4. The quality assessment and validation procedures are then presented in Section 10.8.5.