J/AJ/171/20 TI-DYE. IV. TOI-6448 comoving star candidates (Barber+, 2026)
TESS Investigation-Demographics of Young Exoplanets (TI-DYE).
IV. A Jovian-radius planet orbiting a 34Myr Sun-like star in the Vela
Association.
Barber M.G., Mann A.W., Vanderburg A., Barkaoui K., Collins K.A.,
Carrazco-Gaxiola S., Evans P., Fields M.J., Gillon M., Henry T.J.,
Hesse K.M., Jao W.-C., Jehin E., Jenkins S., Johns T., Rodriguez D.R.,
Schwarz R.P., Storch W.C., Watkins C.N., Wilkin F.P.
<Astron. J., 171, 20 (2026)>
=2026AJ....171...20B 2026AJ....171...20B
ADC_Keywords: Exoplanets; Photometry; Optical; Spectra, infrared; YSOs;
Clusters, open; Radial velocities
Keywords: Exoplanets ; Young star clusters ; Transit photometry ; Transits ;
Young stellar objects
Abstract:
The discovery of infant (<50Myr), close-in (<30-day-period) planets is
vital in understanding the formation mechanisms that lead to the
distribution of mature transiting planets as discovered by Kepler.
Despite several discoveries in this age bin, the sample is still too
small for a robust statistical comparison to older planets. Here we
report the validation of TOI-6448b, an 8.8±0.8R⊕ planet on a
14.8-day orbit. TOI-6448 was previously identified to be a likely
member of Vela Population IV. We confirm the star's membership and
rederive the age of the cluster using isochrones, variability, and
gyrochronology. We find the star, and thus planet, to be 34±3Myr.
Like other young planets, TOI-6448 b lands in a region of parameter
space with few older planets. While just one data point, this fits
with prior findings of an excess of 5-11R⊕ planets around
young stars far beyond what can be explained by reduced sensitivity at
young ages. Our ongoing searches of Vela, Taurus-Auriga, Sco-Cen, and
Orion are expected to reveal dozens more <50Myr transiting planets.
Description:
TOI-6448 was first observed by TESS in Sector 33 from 2020 December 18
to 2021 January 13 and reobserved in sectors 34 (2021 January 14-2021
February 8), 61 (2023 January 18-2023 February 12), and 87 (2024
December 18-2025 January 14). For Sector 87, the target was observed
in short-cadence (20s and 2min light curves), and in the remaining
sectors, the target was only observed in TESS full frame images. The
TESS data used in this analysis can be found in MAST
(doi=10.17909/t9-st5g-3177, doi=10.17909/3y7c-wa45). We also acquired
ground-based time-series follow-up photometry of the field around
TOI-6448 as part of the TESS Follow-up Observing Program, as well as
ground-based spectroscopy.
We observed an ingress window and a full transit window of TOI-6448.01
on UTC 2024 November 25 and UTC 2024 December 9, respectively, in
Sloan g' band from Las Cumbres Observatory Global Telescope (LCOGT)
0.35m network nodes. The November light curve was observed from Teide
Observatory on the island of Tenerife (TEID), and the December light
curve was observed from South Africa Astronomical Observatory (SAAO)
near Sutherland, South Africa.
We used the TRAPPIST-South (TRAnsiting Planets and PlanetesImals Small
Telescope) telescope to observe a full transit of TOI-6448.01 on UT
2024 February 17. TRAPPIST-South is a 0.6m Ritchey-Chretien
telescope located at La Silla Observatory in Chile. The observations
were conducted in the I+z filter with an exposure time of 50s.
We observed a full transit in Johnson-Cousins Rc band on UT 2024
February 17 using the Evans 0.51m telescope at El Sauce Observatory in
Coquimbo Province, Chile. The photometric data were obtained from
150x120s exposures, after standard calibration.
We observed TOI-6448 on UT 2025 May 23 using the CHIRON echelle
spectrometer on the SMARTS 1.5m telescope at the Cerro Tololo
Inter-American Observatory in Chile. The exposure was 20min and
utilized the fiber mode. CHIRON fiber mode covers 4100-8700Å with
a resolution R∼25,000.
We observed TOI-6448 on UT 2025 May 26 using the Magellan Inamori
Kyocera Echelle (MIKE) instrument on the Magellan Clay telescope at
the Las Campanas Observatory in Chile using the 1" slit and both arms,
i.e. red (R∼22,000) and blue (R∼28,000), simultaneously, covering
3350-9500Å in a 15min exposure.
Objects:
--------------------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------------------
08 09 22.47 -47 21 03.4 Vela Association = Ass Vel OB 2
07 20 40.90 -33 55 20.4 TOI-6448 = TIC 320411045
07 20 40.90 -33 55 20.4 TOI-6448b = TOI-6448.01
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table7.dat 88 393 Candidate comoving stars
--------------------------------------------------------------------------------
See also:
II/328 : AllWISE Data Release (Cutri+ 2013)
II/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
J/A+A/558/A53 : MW global surv. of star clusters. II. (Kharchenko+, 2013)
J/ApJ/779/188 : Spectra of nearby late K and M Kepler stars (Mann+, 2013)
J/MNRAS/443/2561 : CONCH-SHELL catalog of nearby M dwarfs (Gaidos+, 2014)
J/ApJ/825/19 : Mass-rad. relationship for planets with Rp<4 (Wolfgang+, 2016)
J/AJ/154/224 : Transiting planets in young clusters from K2 (Rizzuto+, 2017)
J/AJ/155/225 : M dwarf stars rotat. broadening measurements (Kesseli+, 2018)
J/AJ/156/259 : Robo-AO detected close binaries in Gaia DR2 (Ziegler+, 2018)
J/A+A/623/A108 : Age of 269 GDR2 open clusters (Bossini+, 2019)
J/A+A/626/A17 : Young population in Vela-Puppis region (Cantat-Gaudin+, 2019)
J/AJ/160/108 : Gaia-Kepler stellar properties cat. II. Planets (Berger+, 2020)
J/ApJ/903/96 : The µTau Association (MUTA) (Gagne+, 2020)
J/AJ/160/279 : Untangling the Gal. II. Structure within 3kpc (Kounkel+, 2020)
J/A+A/650/A66 : DS Tuc A radial velocity curve (Benatti+, 2021)
J/AJ/162/176 : The solar neighborhood. XLVIII. (Paredes+, 2021)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
J/AJ/161/171 : THYME. V. Discov. a new stellar association (Tofflemire+, 2021)
J/AJ/164/215 : Candidate members of Cep-Her, RSG-5 and CH-2 (Bouma+, 2022)
J/AJ/163/247 : HIRES, PEPSI & TRES radial vel. of V1298 Tau (Johnson+, 2022)
J/ApJS/259/33 : Faint-star TOIs from TESS Primary Mission (Kunimoto+, 2022)
J/other/Sci/377.1211 : RV and LC of 8 M dwarf stars with planets (Luque+, 2022)
J/AJ/163/156 : THYME. VI. TOI-1227 radial velocity (Mann+, 2022)
J/ApJ/931/156 : 3D morph. of open clusters with Gaia EDR3. II. (Pang+, 2022)
J/AJ/166/62 : New HIRES radial velocity data for V1298 Tau (Blunt+, 2023)
J/ApJS/265/12 : Neighboring open clusters with Gaia DR3 (Qin+, 2023)
J/A+A/675/A68 : ML tool for open cluster membership (van Groeningen+, 2023)
J/AJ/165/85 : THYME. IX. MELANGE-4 association members (Wood+, 2023)
J/AJ/168/41 : THYME. X. MELANGE-5 association cand. members (Thao+, 2024)
J/AJ/168/297 : JWST transmission spectrum of HIP 67522b (Thao+, 2024)
J/AJ/167/210 : <200Myr planet's hosts TESS parameters (Vach+, 2024)
J/AJ/170/32 : LCs & comoving stars of TOI-2076 from TESS (Barber+, 2025)
http://archive.stsci.edu/missions-and-data/tess : MAST archive for TESS
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 (I/355) source identifier
21- 28 F8.4 deg RAdeg Right ascension (J2016)
30- 37 F8.4 deg DEdeg Declination (J2016)
39- 43 F5.2 mag Gmag [5.37/20.26] Gaia G-band apparent magnitude
45- 49 F5.2 mag BP-RP [-0.27/3.6]? Gaia BP-RP color
51- 54 F4.2 km/s Voff [0/1] Velocity offset
56- 60 F5.2 km/s RVexp [17.21/20.29] Expected radial velocity for
membership
62- 67 F6.2 km/s RV [-55.55/54.85]? Radial velocity (1)
69- 73 F5.2 km/s e_RV [0.99/14.59]? Uncertainty in RV (1)
75- 80 F6.3 d Prot [0.213/20]? Rotation period
82- 86 F5.3 d e_Prot [1e-3/2.27]? Uncertainty in Prot
88 A1 --- Vela Identified in Vela Population IV in
Cantat-Gaudin+2019 (J/A+A/626/A17)? (2)
--------------------------------------------------------------------------------
Note (1): From Gaia DR3 (I/355).
Note (2): 221 yes, 172 no.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Barber et al. Pap II 2024ApJ...973L..30B 2024ApJ...973L..30B Cat. J/ApJ/973/30
Barber et al. Pap III 2025AJ....170...32B 2025AJ....170...32B Cat. J/AJ/170/32
Barber et al. Pap IV 2026AJ....171...20B 2026AJ....171...20B This catalog
(End) Prepared by [AAS], Robin Leichtnam [CDS] 14-Apr-2026