Page History

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65      Teff       The effective temperatures come from one of four sources, in the following order of preference: (1) the Cool Dwarf list or the Hot Subdwarf list; (2) spectroscopic catalogs (see Column 64); (3) dereddended V-Ks color; and (4) non-dereddened V-Ks color.  We no longer allow stars with effective temperature not corrected for reddening to enter the CTL, except for stars in the bright star list.

66 66      e_Teff    The SPOCS and GALAH catalogs do not provide uncertainties for for effective temperatures; 25K and 41K were assigned, respectively, based on the reported statistical error from those catalogs.

67      Logg      Surface gravity is calculated using the nominal formula: log10(G*M * Msun/(R * Rsun)^2). Where Msun is the mass of the Sun, G is the gravitational constant, Rsun is the Radius of the Sun, M is the mass of the star (column 73) and R is the radius of the star (column 71). Some stars may have unphysical log(g) values, such as log(g) > 4.8. If

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the star’s stellar characteristics were calculated from de-reddened effective temperature or from a spectroscopic temperature, their priorities have been set to 0 to not prioritize stars with low quality stellar characteristics but the log(g) value remains to keep the TIC internally consistent.

68 68     e_Logg    For stars which do not have spectroscopic log(g) measured, we define define the error in the surface gravity as sqrt((M_e/M)^2+(2*R_e/R)^2), where M is the mass of the star (column 73), M_e is the mass error (column 74), R is the radius of the star (column 71) and R_e is the radius error of the star (column 72). For stars with spectroscopic log(g) from a

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single observation, the error was copied. For stars with multiple observations in the same catalog, the error listed in the TIC is a combination of each single observation’s error added in quadrature. The SPOCS and GALAH catalogs do not provide uncertainties for surface gravities; 0.028 and 0.17 dex were assigned, respectively, based on the reported statistical error from those catalogs.

70      e_M/H     For stars with spectroscopic metallicity from a single observation, thethe error was copied from the relevant catalog. For stars with multiple multiple observations in the same catalog, the error listed in the TIC is a combination of each single observation’s error added in quadrature. The SPOCS and GALAH catalogs do not provide uncertainties for metallicities; 0.10 and 0.05 dex were assigned, respectively, based on the reported statistical error from these catalogs.

71     Radius     The stellar radii were estimated using a variety of techniques, in thethe following order of preference: (1) radii provided by the specially curated Cool Dwarf list or the Hot Subdwarf list; (2) using the Gaia parallax and bolometric corrections; (3) spectroscopic relations from Torres et al. 2010, A&ARv, 18, 67; and (4) a unified relation based on measured radii for eclipsing binaries as well as simulations using Galactic structure models.

73     Mass        If an object’s mass is provided in the specially curated cool dwarf list or or hot subdwarf listit is included in the TIC. Otherwise, the stellar masses were estimated using an unified relation based on measured masses for eclipsing binaries as well as simulations using Galactic structure models (see section 3.2.2 in the full documentation for details).

75 Rho 75     Rho         The density in solar units is calculated using the formula M/R^3, where M M is the mass of the star (column 73) and R is the radius of the

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star (column 71).

76 76    Rho_e e     The error in the density is calculated using the following formula: 3.0*Rho*(R_e/R), where Rho is the density (column 75), R_e is the error in the radius (column 72) and R is the radius of the star (column 71).

77 77    LumClass This is a boolean dwarf flag. If this is set, LumClass = DWARF, oror otherwise GIANT.  SUBGIANT is not used at present. However, the DWARF flag for TIC-6 effectively means that the star is either a dwarf or a subgiant, based on reduced proper motion cuts.

78 Lum 78    Lum          The luminosity is calculated using the following formula and defined in in solar units: R^2/(Teff/5772)^4, where R is the radius of the star (column 73) and Teff is the effective temperature (column 65).

79 79    Lum_e e      The error in the luminosity is calculated using the following formula: 2.0* L * (R_e / R). Where L is the luminosity (column 78), R_e is the radius error (column 74) and R is the radius (column 73). If the luminosity error was found to be larger than the luminosity, it was set to be equal to the luminosity.

82    E(B-V)      Stars for which E(B-V) > 1.5 have their E(B-V) values set to a maximum maximum of 1.5.

85   contratio   The contamination ratio is defined as the nominal flux from the the contaminants divided by the flux from the source. Flux contamination is calculated for all stars in the CTL. Contaminants are searched for within 10 TESS pixels of the target and the contaminating flux is calculated within a radius that depends on the target’s TESS magnitude (Tmag, column 61). The PSF is modeled using a 2D-Gaussian based on preliminary PSF measurements from the SPOC. See section 3.2.3 of the full documentation for details.

88 priority 88    priority      Priority of target for observation. This is a floating-point value ranging ranging from 0 to 1, where 1 is highest priority. The priority is based on the relative ability of TESS to detect small planetary transits, and is calculated using the radius of the star, the contamination ratio, and the total expected photometric precision. Stars are given a boost factor to their priority which scales with a probabilistic model of the expected number of sectors any given star could fall in. Typically, the closer the star is to the Ecliptic North or South pole, the larger the boost factor. Stars close to the Galactic Plane (|b|<15) have been de-boosted by a factor of 0.1 since we generally have a poor understanding of their true reddening, unless they are in the specially curated Cool Dwarf list (see Muirhead et al. 2017).

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 The formula is defined as:

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 Ns(R1.5(+1)) where Ns is the expected number of  TESS sectors to observe the star; R is the radius of the star (column 71), ε is the contamination ratio (column 87) and 𝛔 is the expected photometric precision of the star based on the TESS magnitude (column 61). The priority is normalized by the priority for a star with R = 0.1 solar, Ns = 12.654 sectors, ε = 0 contamination and 𝛔 = 61.75 ppm.

Some stars will have distinct priorities:

a. Stars with log(g) values that are greater than 4.8 and temperature sources from ‘dered’ or ‘spec’ have their priority values set to 0 to avoid biases from Giant stars masquerading as dwarfs.

b. Stars in the bright star list always have their priority set to 1.

c. Stars with absolute ecliptic latitudes (column 28) less than ~6 are not expected to be observed as part of the main mission due to a gap in camera coverage between the Southern and Northern observations. Therefore, their Ns values are 0 and thus the priority is 0.

Known Issues and Quirks:

There are a number of minor issues which have been identified by the TSWG. We expect to address these issues in a future version of the TIC. The issues include:

1. All coordinates are for the epoch of observation (often 2MASS or SDSS for extended objects). Epochs are not currently supplied.

2. Because some stars have poor quality 2MASS photometry flags (such as ‘D’, ‘U’), offsets where applied to G, V, J, H, or Ks magnitudes to provide a more realistic TESS magnitude but may be different from the true value by a magnitude or more.  

3. ‘allen’ is a deprecated flag that should be replaced by the spline flag.

4. Some stars will show an error in the stellar density which is larger than the density itself. In these cases, the error should be interpreted as equal to the density.

5. The error in the luminosity currently only reflects the effect of the radius error but should also include the effects of temperature.

6. The following 13 stars do not have a TESS magnitude and should be ignored in TIC-6.

1. TIC-IDS: 75834098, 144190256, 158983365, 101677906, 122564545, 147784016, 180764901, 6059840, 459225192, 229259238, 247903820, 590866, 54776047

7. Due to the preference of proper motion catalogs which are based on PPMXL, there is structure in the distribution of high priority candidates mainly above declinations larger than -30 deg.

8. Stars which have ecliptic latitudes between -6 and 6 degree have priorities set to 0, unless they are in the bright star list. This “gap” in priority is meant to mimic the expected gap in camera coverage for the 2 year primary TESS mission.

9. Some bright stars may have nearby impostor stars with similar magnitudes that lie along diffraction spikes from 2MASS photometry. Users can identify these impostors by checking 2MASS quality flags for very poor photometry (such as ‘D’, ‘E’, ‘F’, ‘U’). These objects should be removed in future versions of the TIC.

Column Number, Column Name, Column Data Type and Brief Description: