J/A+A/684/A69 beta Pic Moving Group photometry (Gratton+, 2024)
Implications of the discovery of AF Lep b The mass-luminosity relation for
planets in the beta Pic Moving Group and the L-T transition for young
companions and free-floating planets.
Gratton R., Bonavita M., Mesa D., Zurlo A., Marino S., Desidera S.,
D'Orazi V., Rigliaco E., Squicciarini V., Nogueira P.H.
<Astron. Astrophys. 684, A69 (2024)>
=2024A&A...684A..69G 2024A&A...684A..69G (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Photometry, infrared ;
Effective temperatures ; Stars, masses
Keywords: planets and satellites: atmospheres -
planets and satellites: formation -
planets and satellites: fundamental parameters
Abstract:
Dynamical masses of young planets aged between 10 and 200Myr detected
in imaging play a crucial role in shaping models of giant planet
formation. Regrettably, only a few such objects possess these
characteristics. Furthermore, the evolutionary pattern of young
sub-stellar companions in near-infrared colour-magnitude diagrams
might diverge from free-floating objects, possibly due to differing
formation processes.
The recent identification of a giant planet around AF Lep, part of the
beta Pic moving group (BPMG), encouraged us to re-examine these points.
We considered updated dynamical masses and luminosities for the
sub-stellar objects in the BPMG. In addition, we compared the
properties of sub-stellar companions and free-floating objects in the
BPMG and other young associations remapping the positions of the
objects in the colour-magnitude diagram into a dustiness-temperature
plane.
We found that cold-start evolutionary models do not reproduce the
mass-luminosity relation for sub-stellar companions in the BPMG. This
aligns rather closely with predictions from 'hot start' scenarios
and is consistent with recent planet formation models. We obtain
rather good agreement with masses from photometry and the remapping
approach compared to actual dynamical masses. We also found a strong
suggestion that the near-infrared colour-magnitude diagram for young
companions is different from that of free-floating objects belonging
to the same young associations.
If confirmed by further data, this last result would imply that cloud
settling - which likely causes the transition between L and T
spectral type - occurs at a lower effective temperature in young
companions than in free-floating objects. This might tentatively be
explained with a different chemical composition.
Description:
The Appendices contain a compilation of data for sub-stellar
companions and free-floating objects belonging to young and
intermediate age associations used in this paper, and the derivation
of a uniform set of temperature and masses for them.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 146 34 Photometry for sub-stellar objects in the BPMG
tablea2.dat 193 202 Photometry for sub-stellar objects in other
young moving groups
tableb1.dat 71 131 Masses of sub-stellar objects with ages in the
range 10-200Myr derived using AMES models
refs.dat 67 53 References
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See also:
J/A+A/583/A85 : Binaries in beta Pic moving group (Alonso-Floriano+, 2015)
J/AJ/140/119 : β Pic and AB Dor moving groups members (Schlieder+, 2010)
J/AJ/143/80 : Low-mass stars of beta Pic and AB Dor groups (Schlieder+, 2012)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Code Code (G1)
3- 27 A25 --- Name Name
29- 32 F4.1 % Pmemb Membership probability
34- 38 F5.2 mas plx Photometric parallax
40- 45 F6.3 mag Jmag ?=- J magnitude
47- 51 F5.3 mag e_Jmag ?=- J magnitude error
53- 58 F6.3 mag Hmag ?=- H magnitude
60- 64 F5.3 mag e_Hmag ?=- H magnitude error
66- 71 F6.3 mag Kmag ?=- K magnitude
73- 77 F5.3 mag e_Kmag ?=- K magnitude error
79- 83 F5.2 mag JMAG ?=- Absolute J magnitude
85- 89 F5.3 mag e_JMAG ?=- Absolute J magnitude error
91- 95 F5.2 mag HMAG ?=- Absolute H magnitude
97-100 F4.2 mag e_HMAG ?=- Absolute H magnitude error
102-106 F5.2 mag KMAG ?=- Absolute K magnitude
108-111 F4.2 mag e_KMAG ?=- Absolute K magnitude error
113-117 F5.2 mag J-K ?=- J-K colour index
119-122 F4.2 mag e_J-K ?=- J-K colour index error
124-146 A23 --- Ref Reference, in refs.dat file
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Group Moving group name
24- 49 A26 --- Name Name
52- 55 F4.1 % Pmemb ?=- Membership probability
57- 62 F6.2 mas plx Photometric parallax
64- 69 F6.3 mag Jmag ?=- J magnitude
71- 75 F5.3 mag e_Jmag ?=- J magnitude error
77- 82 F6.3 mag Hmag ?=- H magnitude
84- 88 F5.3 mag e_Hmag ?=- H magnitude error
90- 95 F6.3 mag Kmag ?=- K magnitude
97-101 F5.3 mag e_Kmag ?=- K magnitude error
103-107 F5.2 mag JMAG ?=- Absolute J magnitude
109-112 F4.2 mag e_JMAG ?=- Absolute J magnitude error
114-118 F5.2 mag HMAG ?=- Absolute H magnitude
120-123 F4.2 mag e_HMAG ?=- Absolute H magnitude error
125-129 F5.2 mag KMAG ?=- Absolute K magnitude
131-134 F4.2 mag e_KMAG ?=- Absolute K magnitude error
136-140 F5.2 mag J-K ?=- J-K colour index
142-145 F4.2 mag e_J-K ?=- J-K colour index error
147-190 A44 --- Ref Reference, in refs.dat file
193 A1 --- Note [b] b Binary
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Code Code (G1)
3- 26 A24 --- Name Name
29- 31 I3 Gyr Age Age
33- 36 I4 K Teff1 ?=- Effective temperature (BC)
38- 39 I2 K e_Teff1 ? Effective temperature (BC) error
41- 44 I4 K Teff2 Effective temperature (remap)
46- 48 I3 K e_Teff2 Effective temperature (remap) error
50- 54 F5.2 --- r r parameter (1)
56- 59 F4.2 --- e_r r parameter error
61- 65 F5.2 MJup Mass Mass
67- 71 F5.2 MJup e_Mass Mass error
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Note (1): To show the relation between the effective temperature and the
transition from cloudy to clean atmospheres, we remapped the colour-magnitude
diagram (cmd) into an effective temperature - relevance of dust plane.
In our approach, this last effect is represented by a parameter r.
By linear interpolation between these points, we can define a new isochrone
that corresponds to any arbitrary value of r, where r=0 for the AMES-COND
isochrones and r=1 for the AMES-DUSTY one.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 27 A27 --- Ref Reference code
28- 46 A19 --- BibCoe BibCode
48- 67 A20 --- Com Comments
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Global notes:
Note (G1): Code as follows:
c = Companions
f = Free floating objects
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Jun-2024