J/MNRAS/499/L111 Stars in the Earth transit zone (Kaltenegger+, 2020)
Which stars can see Earth as a transiting exoplanet?
Kaltenegger L., Pepper J.
<Mon. Not. R. Astron. Soc., 499, L111-115 (2020)>
=2020MNRAS.499L.111K 2020MNRAS.499L.111K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Stars, diameters ;
Stars, masses ; Milky Way ; Effective temperatures ;
Stars, distances ; Parallaxes, trigonometric ; Optical
Keywords: astrobiology - catalogues -
planets and satellites: terrestrial planets -
planets and satellites: detection - methods: observational -
extraterrestrial intelligence
Abstract:
Transit observations have found the majority of exoplanets to date.
Also spectroscopic observations of transits and eclipses are the most
commonly used tool to characterize exoplanet atmospheres and will be
used in the search for life. However, an exoplanet's orbit must be
aligned with our line of sight to observe a transit. Here, we ask,
from which stellar vantage points would a distant observer be able to
search for life on Earth in the same way? We use the TESS Input
Catalog and data from Gaia DR2 to identify the closest stars that
could see Earth as a transiting exoplanet: We identify 1004
main-sequence stars within 100 parsecs, of which 508 guarantee a
minimum 10-h long observation of Earth's transit. Our star list
consists of about 77 percent M-type, 12 percent K-type, 6 percent
G-type, 4 percent F-type stars, and 1 percent A-type stars close to
the ecliptic. SETI searches like the Breakthrough Listen Initiative
are already focusing on this part of the sky. Our catalogue now
provides a target list for this search. As part of the extended
mission, NASA's TESS will also search for transiting planets in the
ecliptic to find planets that could already have found life on our
transiting Earth.
Description:
To identify the stars in the Earth transit zone we use TIC-8 and the
accompanying Candidate Target List (CTL-8.01; Stassun et al.
2019AJ....158..138S 2019AJ....158..138S, Cat. IV/38). TIC-8 contains roughly 1.7 billion
stars, in a magnitude-limited sample primarily constrained by the
magnitude limits of Gaia DR2 and 2MASS. The CTL contains a selection
of 9.5 million mostly bright, cool, dwarf stars from the TIC, along
with physical parameters calculated based on the empirical properties
of the constituent catalogues. The CTL also includes a separate set of
cool dwarfs, mostly late K- and M-type dwarfs, assembled from the Cool
Dwarf Catalog (Muirhead et al. 2018AJ....155..180M 2018AJ....155..180M, Cat.
J/AJ/155/180).
There are about 10.3 million TIC objects in the Earth transit zone
(ETZ). In order to select nearby main-sequence stars with reliably
measured stellar parameters, we limit our search to the CTL. We select
from all stars in the ETZ, spanning the ecliptic latitudes of
-0.264° to +0.264°, from the CTL with distances out to 100pc,
and identify 1004 main-sequence stars.
While no Earth-like planets have been detected around the identified
stars in the ETZ yet, we provide the orbital distance in au (Earth
analogue orbital separation, aEA) as well as orbital period in days
(Earth analogue orbital period, PerEA) for a nominal planet which
receives similar irradiation as Earth for future searches (see Table 1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 288 1004 Closest stars in the Earth transit zone
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See also:
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 I10 --- TIC TESS Input Catalog identifier (1)
12- 19 F8.5 mag Tmag TESS magnitude (1)
21- 29 F9.5 mag Vmag ?=-99 V-band magnitude (1)
31- 38 F8.4 mag e_Vmag ?=-99 Error on Vmag (1)
40- 46 F7.2 K Teff Effective temperature (1)
48- 55 F8.5 pc Dist Distance derived from Gaia DR2 parallax (1)
57- 63 F7.5 pc e_Dist Error on Dist (1)
65- 72 F8.6 Rsun R Stellar radius (1)
74- 85 F12.8 Rsun e_R ?=-99 Error on radius (1)
87- 95 F9.7 Msun Mass Stellar mass (1)
97- 107 F11.7 Msun e_Mass ?=-99 Error on Mass (1)
109- 120 F12.9 Lsun L Luminosity (1)
122- 134 F13.9 Lsun e_L ?=-99 Error on L (1)
136- 148 F13.9 deg RAdeg Right ascension (J2000) (1)
150- 162 F13.9 deg DEdeg Declination (J2000) (1)
164- 176 F13.9 deg ELON Ecliptic longitude (1)
178- 189 F12.9 deg ELAT Ecliptic latitude (1)
191- 203 F13.9 deg GLON Galactic longitude (1)
205- 217 F13.9 deg GLAT Galactic latitude (1)
219- 227 F9.5 mas plx Gaia DR2 parallax
229- 237 F9.7 mas e_plx Error on parallax
239- 254 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
256- 260 F5.3 AU aEA Earth analogue orbital separation
262- 268 F7.2 d PerEA Earth analogue orbital period
270- 288 I19 --- GaiaDR2 Gaia DR2 source identifier
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Note (1): Values taken from TESS (Stassun et al. 2019AJ....158..138S 2019AJ....158..138S,
Cat. IV/38)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 14-Sep-2023