We present the first detection of atomic emission lines from the atmosphere of an exoplanet. We detect neutral iron lines from the dayside of KELT-9b (Teq ∼ 4000 K). We combined thousands of ...spectrally resolved lines observed during one night with the HARPS-N spectrograph (R ∼ 115,000), mounted at the Telescopio Nazionale Galileo. We introduce a novel statistical approach to extract the planetary parameters from the binary mask cross-correlation analysis. We also adapt the concept of contribution function to the context of high spectral resolution observations, to identify the location in the planetary atmosphere where the detected emission originates. The average planetary line profile intersected by a stellar G2 binary mask was found in emission with a contrast of 84 14 ppm relative to the planetary plus stellar continuum (40% 5% relative to the planetary continuum only). This result unambiguously indicates the presence of an atmospheric thermal inversion. Finally, assuming a modeled temperature profile previously published, we show that an iron abundance consistent with a few times the stellar value explains the data well. In this scenario, the iron emission originates at the 10−3-10−5 bar level.
Abstract
K2-136 is a late-K dwarf (0.742 ± 0.039
M
⊙
) in the Hyades open cluster with three known, transiting planets and an age of 650 ± 70 Myr. Analyzing K2 photometry, we found that planets ...K2-136b, c, and d have periods of 8.0, 17.3, and 25.6 days and radii of 1.014 ± 0.050
R
⊕
, 3.00 ± 0.13
R
⊕
, and 1.565 ± 0.077
R
⊕
, respectively. We collected 93 radial velocity (RV) measurements with the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph (Telescopio Nazionale Galileo) and 22 RVs with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectrograph (Very Large Telescope). Analyzing HARPS-N and ESPRESSO data jointly, we found that K2-136c induced a semi-amplitude of 5.49 ± 0.53 m s
−1
, corresponding to a mass of 18.1 ± 1.9
M
⊕
. We also placed 95% upper mass limits on K2-136b and d of 4.3 and 3.0
M
⊕
, respectively. Further, we analyzed Hubble Space Telescope and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has ∼75% the radius of Neptune but is similar in mass, yielding a density of
3.69
−
0.56
+
0.67
g cm
−3
(∼2–3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets’ atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time.
We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, V = 13.07, Ks = 8.204, Rs = 0.374 R , Ms = 0.401 M , d = 22 pc). The two planet ...candidates are identified in a single Transiting Exoplanet Survey Satellite sector and validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of Pb = 0.77, Pc = 12.25 days and sizes rp,b = 1.33 0.07, rp,c = 2.30 0.16 R⊕, the two planets span the radius valley in period-radius space around low-mass stars, thus making the system a laboratory to test competing theories of the emergence of the radius valley in that stellar mass regime. By combining 63 precise radial velocity measurements from the High Accuracy Radial velocity Planet Searcher (HARPS) and HARPS-N, we measure planet masses of and M⊕, which indicates that LTT 3780b has a bulk composition consistent with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope. We show that the recovered planetary masses are consistent with predictions from both photoevaporation and core-powered mass-loss models. The brightness and small size of LTT 3780, along with the measured planetary parameters, render LTT 3780b and c as accessible targets for atmospheric characterization of planets within the same planetary system and spanning the radius valley.
A spectroscopic test for substellar objects MAGAZZU, A; MARTIN, E. L; REBOLO, R
Astrophysical journal/The Astrophysical journal,
02/1993, Letnik:
404, Številka:
1
Journal Article
K2-136 is a late-K dwarf (\(0.742\pm0.039\) M\(_\odot\)) in the Hyades open cluster with three known, transiting planets and an age of \(650\pm70\) Myr. Analyzing K2 photometry, we found that planets ...K2-136b, c, and d have periods of \(8.0\), \(17.3\), and \(25.6\) days and radii of \(1.014\pm0.050\) R\(_\oplus\), \(3.00\pm0.13\) R\(_\oplus\), and \(1.565\pm0.077\) R\(_\oplus\), respectively. We collected 93 radial velocity measurements (RVs) with the HARPS-N spectrograph (TNG) and 22 RVs with the ESPRESSO spectrograph (VLT). Analyzing HARPS-N and ESPRESSO data jointly, we found K2-136c induced a semi-amplitude of \(5.49\pm0.53\) m s\(^{-1}\), corresponding to a mass of \(18.1\pm1.9\) M\(_\oplus\). We also placed \(95\)% upper mass limits on K2-136b and d of \(4.3\) and \(3.0\) M\(_\oplus\), respectively. Further, we analyzed HST and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has \(\sim\)75% the radius of Neptune but is similar in mass, yielding a density of \(3.69^{+0.67}_{-0.56}\) g cm\(^{-3}\) (\(\sim\)2-3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets' atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time.
IRSPEC observations of planetary nebulae Magazz, Antonio; Strazzulla, Giovanni
Astrophysics and space science,
9/1990, Letnik:
171, Številka:
1-2
Journal Article
Recenzirano
Infrared spectra of planetary nebulae were obtained in the 3.0-3.8-micron range using IRSPEC, the ESO grating infrared spectrograph, attached to the 3.6-m telescope. Evidence was found of an ...evolution of the carriers of the unidentified emission bands in the 3-micron region, and the observed behavior was explained in terms of ion irradiation from fast stellar wind. (Author)
Astron.Astrophys. 429 (2005) 939-943 We present radial-velocity measurements obtained using high- and
intermediate-resolution spectroscopic observations of the classical T Tauri
star UZ Tau East ...obtained from 1994 to 1996. We also provide measurements of
H$\alpha$ equivalent widths and optical veiling. Combining our radial-velocity
data with those recently reported by Prato et al. (2002), we improve the
orbital elements for this spectroscopic binary. The orbital period is
18.979$\pm$0.007 days and the eccentricity is e=0.14. We find variability in
the H$_\alpha$ emission and veiling, signposts of accretion, but at periastron
passage the accretion is not as clearly enhanced as in the case of the binary
DQ Tau. The difference in the behaviour of these two binaries is consistent
with the hydrodynamical models of accretion from circumbinary disks because UZ
Tau East has lower eccentricity than DQ Tau. It seems that enhanced periastron
accretion may occur only in systems with very high eccentricity (e$>$0.5).
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