J/AJ/169/45 Small planets transiting A-type stars with TESS (Giacalone+, 2025)
Small and close-in planets are uncommon around A-type stars.
Giacalone S., Dressing C.D.
<Astron. J., 169, 45 (2025)>
=2025AJ....169...45G 2025AJ....169...45G
ADC_Keywords: Stars, A-type; Photometry, infrared; Optical; Exoplanets
Keywords: Exoplanets ; Transits ; Extrasolar rocky planets ;
Extrasolar gaseous planets ; Exoplanet formation ;
Exoplanet evolution ; Exoplanet detection methods ;
Transit photometry ; Exoplanet astronomy
Abstract:
The Kepler and K2 missions enabled robust calculations of planet
occurrence rates around FGKM-type stars. However, these missions
observed too few stars with earlier spectral types to tightly constrain
the occurrence rates of planets orbiting hotter stars. Using TESS, we
calculate the occurrence rate of small(1R⊕<Rp<8R⊕),
close-in (Porb<10d) planets orbiting A-type stars for the first
time. We search a sample of 20,257 bright (6<T<10) A-type stars for
transiting planets using a custom pipeline and vet the detected
signals, finding no reliable small planets. We characterize the
pipeline completeness using injection-recovery tests and determine the
3σ upper limits of the occurrence rates of close-in
sub-Saturns (4R⊕<Rp<8R⊕),
sub-Neptunes (2R⊕<Rp<4R⊕), and
super-Earths (1R⊕<Rp<2R⊕). We find upper limits of
2.2±0.4 sub-Saturns and 9.1±1.8 sub-Neptunes per 1000 A-type
stars, which may be more than 3x and 6x lower than Kepler-era
estimates for Sun-like stars. We calculate an upper limit of 186±34
super-Earths per 1000 A-type stars, which may be more than 1.5x lower
than that for M dwarfs. Our results hint that small, close-in planets
become rarer around early-type stars and that their occurrence rates
decrease faster than that of hot Jupiters with increasing host star
temperature. We discuss plausible explanations for these trends,
including star-disk interactions and enhanced photoevaporation of
planet atmospheres.
Description:
We begin by defining a sample of main-sequence A-type stars around
which to search for planets. We build this sample by querying version
8.2 of the TESS Input Catalog (TIC; Stassun+2018, J/AJ/156/102, &
Stassun+2019, IV/38), selecting stars that have all of the following
properties: (1) an effective temperature (Teff) between 7500 and
10,000K, (2) a radius (R*) ≤2.5R☉, (3) a TESS magnitude
(Tmag) between 6 and 10, and (4) a nonzero mass (M*) estimate. In
addition, we require all stars to have data products from the MIT
Quick Look Pipeline (QLP; Huang+, 2020RNAAS...4..204H 2020RNAAS...4..204H, &
Huang+, 2020RNAAS...4..206H 2020RNAAS...4..206H) available on the Mikulski Archive for
Space Telescopes (MAST; http://archive.stsci.edu/).
The final sample consists of 20,257 stars observed in TESS full frame
images between Sectors 1 and 69 (i.e., the first 5yr of the TESS
mission, from 2019 to 2023). Downloaded light curves have cadences of
30min (Sectors 1-26), 10min (Sectors 27-55), and 200s (Sectors 56-69),
and where taken in TESS's red-optical bandpass (600-1000nm).
After flattening and cleaning the raw QLP light curve, we employ an
automated pipeline to detect threshold-crossing events (TCEs) and
eliminate those that display nontransit-like morphologies.
After running the full sample of stars through this automated
pipeline, we recover 299 TCEs. Fourteen of these TCEs correspond to
previously reported TESS Objects of Interest (TOIs;
Guerrero+2021, J/ApJS/254/39), which appear on the Exoplanet Follow-up
Observing Program (ExoFOP) website (http://exofop.ipac.caltech.edu/tess/).
In order to identify reliable planet candidates, we vet these 299 TCEs
manually.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 93 299 Threshold-crossing events detected by the automated
pipeline
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See also:
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
J/A+A/475/677 : X-ray emission from A-type stars (Schroeder+, 2007)
J/PASP/124/1279 : Q3 Kepler's combined photometry (Christiansen+, 2012)
J/MNRAS/422/2024 : X-ray-age relation & exoplanet evaporation (Jackson+, 2012)
J/A+A/537/A120 : Rotational velocities of A-type stars. IV. (Zorec+, 2012)
J/ApJ/767/95 : Improved stellar param. of smallest KIC stars (Dressing+, 2013)
J/A+A/561/A138 : Transiting planets search Matlab/Octave src code (Ofir+, 2014)
J/ApJ/807/45 : Potentially habitable planets orbit. M dwarfs (Dressing+, 2015)
J/ApJ/814/130 : Planet occurrence rates calculated for KOIs (Mulders+, 2015)
J/ApJ/828/46 : ALMA survey of Lupus protoplanetary disks. I. (Ansdell+, 2016)
J/MNRAS/455/3413 : New white dwarf & subdwarf stars: SDSS DR12 (Kepler+, 2016)
J/ApJ/822/86 : False positive proba. for Q1-Q17 DR24 KOIs (Morton+, 2016)
J/ApJ/839/23 : Subdwarf A stars vs ELM WDs radial velocities (Brown+, 2017)
J/A+A/600/A30 : Limb-darkening for TESS satellite (Claret, 2017)
J/AJ/154/109 : California-Kepler Surv. (CKS). III. Planet radii (Fulton+, 2017)
J/AJ/153/71 : Kepler follow-up observation program. I. Imaging (Furlan+, 2017)
J/AJ/153/117 : KOIs companions from high-resolution imaging (Hirsch+, 2017)
J/ApJS/229/30 : Revised stellar propert.: Q1-17 Kepler targets (Mathur+, 2017)
J/A+A/615/A175 : Solar system analogs with HARPS (Barbato+, 2018)
J/ApJS/239/2 : Simulated exoplanets from TESS list of targets (Barclay+, 2018)
J/MNRAS/475/2480 : Extremely-low mass white dwarf star (Pelisoli+, 2018)
J/AJ/155/89 : California-Kepler Survey (CKS). IV. Planets (Petigura+, 2018)
J/AJ/156/102 : The TESS Input Catalog & Candidate Target List (Stassun+, 2018)
J/AJ/156/292 : Effect of close companions on exoplanetary radii (Teske+, 2018)
J/ApJS/235/38 : Kepler planetary cand. VIII. DR25 reliability (Thompson+, 2018)
J/AJ/158/88 : Oscillations in KOI-976's Kepler photometry (Ahlers+, 2019)
J/AJ/157/52 : Radial velocity obs. in super-Earth systems (Bryan+, 2019)
J/AJ/158/75 : Mid-type M dwarfs planet occurr. rates (Hardegree-Ullman+, 2019)
J/AJ/158/109 : Occurrence rates of planets orbiting FGK stars (Hsu+, 2019)
J/MNRAS/486/2169 : White dwarf and subdwarf stars in SDSS DR14 (Kepler+, 2019)
J/AJ/158/13 : The first 300 stars observed by the GPIES (Nielsen+, 2019)
J/AJ/158/141 : Differential phot. & RVs of HAT-P-69 & HAT-P-70 (Zhou+, 2019)
J/AJ/161/36 : 117 exoplanets in habitable zone with Kepler DR25 (Bryson+, 2021)
J/AJ/161/24 : TRICERATOPS predictions for 384 TOIs (Giacalone+, 2021)
J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)
J/AJ/161/134 : Survey of stellar & planetary comp. within 25pc (Hirsch+, 2021)
J/AJ/162/28 : Studying of protoplanetary disks in SFRs with ALMA (Van+, 2021)
J/AJ/164/26 : 102 hot Jup. isochrone analyse & stellar modeling (Hamer+, 2022)
J/A+A/658/A75 : MASCARA-1 b occultation & transit light curves (Hooton+, 2022)
J/ApJS/259/33 : Faint-star TOIs from TESS Primary Mission (Kunimoto+, 2022)
J/AJ/163/67 : 5-55000Å spectrum of TOI 560 (Zhang+, 2022)
J/AJ/163/68 : Fiducial stellar spectrum of HD 63433 (Zhang+, 2022)
J/AJ/166/175 : Pre- and main sequence stars properties (Fernandes+, 2023)
J/AJ/165/265 : Properties of 363 M-dwarfs from TESS (Ment+, 2023)
J/AJ/165/262 : Scaling K2. VI. HIRES/isoclassify stellar param. (Zink+, 2023)
J/AJ/167/55 : Multiple-planet system resonances (Hamer+, 2024)
J/AJ/167/210 : <200Myr planet's hosts TESS parameters (Vach+, 2024)
http://archive.stsci.edu/ : Mikulski Archive for Space Telescopes (MAST)
http://exofop.ipac.caltech.edu/tess/ : Exoplanet Follow-up Observing
Program (ExoFOP) website
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 I11 --- TIC [1503583/470933866] TESS Input Catalog
identifier (J/AJ/156/102, IV/38, IV/39)
13- 16 I4 --- TOI [742/6260]? TESS Object of Interest identifier
(J/ApJS/254/39)
18- 22 F5.2 mag Tmag [5.49/10] TESS band (600-1000nm) apparent
magnitude (1)
24- 28 I5 K Teff [7506/10000] Stellar effective temperature (1)
30- 33 F4.2 solRad R* [1.7/2.6] Stellar radius (1)
35- 38 F4.2 solMass M* [1.4/2.5] Stellar mass (1)
40- 48 F9.4 d T0 [1326/2798] TESS Barycentric Julian Date of
transit midpoint (2)
50- 55 F6.4 d Per [0.52/10] Orbital period (2)
57- 60 I4 ppm Depth [43/2166] Transit depth (2)
62- 93 A32 --- Vet Vetting Outcome (3)
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Note (1): Properties according to the TESS Input Catalog (TIC;
Stassun+2018, J/AJ/156/102, & Stassun+2019, IV/38).
Note (2): TESS Barycentric Julian Date (TBJD) = BJD - 2457000.0;
Estimated by the box least-squares algorithm (BLS;
Kovacs+, 2002A&A...391..369K 2002A&A...391..369K) periodogram.
Note (3): Describes the reason why the Threshold-Crossing Event (TCE) was
classified as a false alarm or false positive, as follows:
Failed SPOC comparison = 211 occurrences
Failed TRICERATOPS analysis = 4 occurrences
False Positive on ExoFOP = 5 occurrences
Nearby eclipsing binary detected = 34 occurrences
Secondary eclipse detected = 44 occurrences
True period twice as long = 1 occurrence
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 13-Nov-2025