It will also provide reliable stellar radii for calculating planetary radii; these will determine which targets receive mission-supported photometric and spectroscopic follow-up.
1997), known cool dwarf stars (Muirhead et al. The nominal parameters we adopt for these calculations are as follows: The flux contamination for ~3.8 million stars in the CTL is shown in Figure 15. Finally, the two elliptical regions at the northern and southern ecliptic poles (| \beta | \gt 78^\circ) are the CVZs. All rights reserved. There are a number of reasons why a given star that might otherwise be of interest for a transit search may have a low or zero priority. Identical to the case for TPFs, if a target was observed in more than one TESS sector, multiple light curve files will be created but they may be made available on the MAST in separate deliveries. Each star is then evaluated according to a metric that prioritizes the star for transit detection, which incorporate the T-mag, stellar radius, estimated flux contamination, and number of sectors of observation. 2018). Large planets on such orbits would be detectable even around fairly faint stars, but the transits would be a bit longer than calculated. Table 9 summarizes the contents of the enhanced CTL provided via the Filtergraph data visualization portal service at the URL filtergraph.vanderbilt.edu/tess_ctl. Brief descriptions are below, but see the MAST Summary page for more details.
Users are encouraged to double-check that the stellar parameters for these stars have been updated with the SPflag = "cdwrf" (Column 64). 2016). The target pixel files are the rawest form of target-specific data that will be available at MAST. We should note that such a step should only be undertaken after careful consideration, because there is also significant value specifically in detecting planets transiting subgiants, which are prime targets for asteroseismic studies (Campante et al. For stars with total proper motions less than 200 mas yr−1, we use HSOY. Find out what sectors / cameras / detectors a target was observed in. For the most part, they belong to the extreme horizontal branch and beyond (spectral types sdB, sdOB, and sdO; see Heber (2016)). Figure 2. To enable false positive determination. Stars that have ecliptic latitudes between −6 and 6 degrees have priorities set to 0, unless they are in the Bright Star list. For stars that are deemed likely to be non-giants according to our reduced-proper-motion (RPM) procedure (see Section 3.2), the {T}_{\mathrm{eff}} is calculated with the above relations but using the dereddened V − KS color (see Section 3.3.1 for the de-reddening procedure). Learn how to contribute TESS-related data products to MAST. The relation for giants was created comparing APASS DR9 Johnson V magnitudes with G − KS color, using 13,580 giants within 400 pc, and with photometric errors in V of σV < 0.1. It includes two main components: All TIC stars brighter than T=13, and estimated stellar radii smaller than 5 RSun While beyond the scope of this paper, in principle one could attempt to estimate the fraction of binaries in the TIC and CTL by using empirical estimates of binarity as functions of spectral type and other factors. © 2020 パパトラ！ All rights reserved. The large distribution of targets with {T}_{\mathrm{eff}} < 4000 K (1) comes from the specially curated Cool Dwarf list, as shown in the top part of Figure 19. This eliminates the spiked feature at 5500 K, which is from the magnitude and {T}_{\mathrm{eff}} limit placed by the selection function of the CTL. Download all full frame images for a given sector. 2013, 2017), Tycho-2 (Høg et al. The relations for dwarfs and sub-giants were created by comparing Johnson V magnitudes measured in Mermilliod (1987) with G − KS color, using 2015 dwarfs and sub-giants within 100 pc and with photometric errors in V of σV < 0.1. However, the majority of TIC stars do not have spectroscopic {T}_{\mathrm{eff}} values available. Because dwarfs are the targets of greatest interest for TESS, we adopt a single set of relations, which are strictly valid for \mathrm{log}g > 3 and [Fe/H] > −0.5. We have also neglected the planet radius in computing the transit duration. 2016). Hot Subdwarfs: This list is meant to identify nearby bright subdwarfs which may be useful for two-minute astroseismology studies. There are four particularly noticeable features of the distribution: (1) the distribution of targets with {T}_{\mathrm{eff}} < 4000; (2) the lack of targets with 5000 < {T}_{\mathrm{eff}} < 4000 K, i.e., "missing" K dwarfs; (3) a peak and sharp drop near {T}_{\mathrm{eff}} = 5500 K; and (4) a peak and smooth decline in the number of targets with {T}_{\mathrm{eff}} > 5500 K. Figure 18.
valid for J − KS > 0.70, where the scatter is 0.17 mag. 2006).
(2010). The smear will be less critical for TESS than was needed for Kepler due to the use of frame-transfer in TESS. In lieu of performing such an analysis, we suggest that the CTL is likely missing essentially all physical binary companions, so the percentage of unknown binaries in the catalog should be essentially the same as the frequency of binaries of different spectral types as given by Duchêne & Kraus (2013). For details of the calculation of σT, see J. Pepper et al. That step allowed us to conduct repeated tests, adjustments, and variations to a number of the procedures described in this paper, in a timeframe that would have been prohibitive when applied to the full TIC.
Determination of Johnson V from UCAC4 (near-V) aperture magnitudes as a function of the measured V − KS color from UCAC4 (using near-V for the color). 2010) and the SDSS extended source catalog (Alam et al. While the majority of CTL stars had their radii and masses calculated from the unified spline relations described above, there are a number of objects that had their parameters calculated from spectroscopy, from parallaxes, taken from the independent cool-dwarf list, or a combination of these methods.