J/AJ/168/175 RV survey searching for GQ Lup B satellites (Horstman+, 2024)
RV measurements of directly imaged brown dwarf GQ Lup B to search for
exosatellites.
Horstman K., Ruffio J.-B., Batygin K., Mawet D., Baker A., Hsu C.-C.,
Wang J.J., Wang Ji, Blunt S., Xuan J.W., Xin Y., Liberman J., Agrawal S.,
Konopacky Q.M., Blake G.A., Do C.R. O, Bartos R., Bond C.Z., Calvin B.,
Cetre S., Delorme J.-R., Doppmann G., Echeverri D., Finnerty L.,
Fitzgerald M.P., Jovanovic N., Lopez R., Martin E.C., Morris E.,
Pezzato J., Ruane G., Sappey B., Schofield T., Skemer A., Venenciano T.,
Wallace J.K., Wallack N.L., Wizinowich P.
<Astron. J., 168, 175 (2024)>
=2024AJ....168..175H 2024AJ....168..175H
ADC_Keywords: Stars, brown dwarf; Exoplanets; Radial velocities;
Spectra, infrared
Keywords: Radial velocity ; Natural satellites (Extrasolar) ;
Exoplanet detection methods ; Direct imaging
Abstract:
GQ Lup B is one of the few substellar companions with a detected
cicumplanetary disk (CPD). Observations of the CPD suggest the
presence of a cavity, possibly formed by an exosatellite. Using the
Keck Planet Imager and Characterizer (KPIC), a high-contrast imaging
suite that feeds a high-resolution spectrograph (1.9-2.5um, R∼35000),
we present the first dedicated radial velocity (RV) observations
around a high-contrast, directly imaged substellar companion, GQLupB,
to search for exosatellites. Over 11 epochs, we find a best and median
RV error of 400-1000m/s, most likely limited by systematic fringing in
the spectra due to transmissive optics within KPIC. With this RV
precision, KPIC is sensitive to exomoons 0.6%-2.8% the mass of GQLup B
(∼30MJup) at separations between the Roche limit and 65 RJup, or
the extent of the cavity inferred within the CPD detected around
GQ_LupB. Using simulations of HISPEC, a high resolution infrared
spectrograph planned to debut at W.M. Keck Observatory in 2026, we
estimate future exomoon sensitivity to increase by over an order of
magnitude, providing sensitivity to less massive satellites
potentially formed within the CPD itself. Additionally, we run
simulations to estimate the amount of material that different masses
of satellites could clear in a CPD to create the observed cavity. We
find satellite-to-planet mass ratios of q>2x10-4 can create
observable cavities and report a maximum cavity size of ∼51RJup
carved from a satellite.
Description:
We carried out 11 observations of GQ Lup B with the Keck Planet Imager
and Characterizer (KPIC; R∼35000) in the K band (1.94-2.49um), a
high-contrast imaging suite that feeds the high-resolution
spectrograph NIRSPEC, between 2021 and 2023.
Since GQ Lup B is at a relatively low elevation in the northern
hemisphere (DEC=-35:39:05.0539), we observed the brown dwarf for only
1.5-2.5hr per night for seven nights between 2023 May and July.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
15 49 12.05 -35 39 05.1 GQ Lup B = V* GQ Lup B
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 39 473 Measured radial velocities (updated version
by the author)
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See also:
J/ApJS/257/45 : BDKP. V. Radial & rot. veloc. of M, L, T dwarfs (Hsu+, 2021)
J/AJ/162/290 : OSIRIS K-band sp. of planets HR8799 b, c & d (Ruffio+, 2021)
J/ApJ/922/L2 : Limits on bin. planets in HR 8799b, c & d (Vanderburg+, 2021)
J/other/NatAs/6.367 : 70 cool giant exoplanets (Kipping+, 2022)
J/A+A/676/A123 : GQ Lup b and GSC 06214-00210 b spectra (Demars+, 2023)
J/A+A/671/A154 : A full transit of nu.02 Lup d (Ehrenreich+, 2023)
J/AJ/165/113 : KPIC radial velocity follow up of HR 7672 B (Ruffio+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD [59328.46/60127.33] Modified Julian Date at
beginning of exposure
11- 17 F7.1 km/s RV [-4800/4800] Measured radial velocity
19- 26 F8.1 km/s e_RV [398/339595] Uncertainty in RV
28- 30 A3 --- --- [Fib]
31 I1 --- Fiber [2/4] Fiber pair number
32- 37 A6 --- --- [_Order]
38- 39 I2 --- Order [31/33] Order (1)
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Note (1): Order as follows:
33 = 2.29-2.34um
32 = 2.36-2.41um
31 = 2.44-2.49um
--------------------------------------------------------------------------------
Acknowledgements:
Horstman, Katelyn A. [khorstma at astro.caltech.edu]
History:
From electronic version of the journal
* 03-Mar-2025: Table 2 fixed by the author; Order 31 corrected
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Feb-2025