Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M⊕ super-Earth and two warm 14.7 and 10.2-M⊕ sub-Neptunes

Hidalgo, D.; Πάλλη, Ε.; Alonso, R.; Fridlund, M.; Nowak, G.; Luque, R.; Hirano, Teruyuki; Justesen, A. B.; Cochran, William D.; Barragán, Oscar; Spina, L.; Rodler, F.; Albrecht, S.; Anderson, D. R.; Amado, P. J.; Bryant, Edward M.; Caballero, J. A.; Cabrera, J.; Csizmadia, Sz.; Dai, Fei; Leon, Jerome de; Deeg, H. J.; Eigmüller, Ph.; Endl, Michael; Erikson, A.; Esposito, M.; Figueira, P.; Georgieva, Iskra; Grziwa, S.; Guenther, E. W.; Hatzes, A. P.; Hjorth, María; Hoeijmakers, H. J.; Kabáth, P.; Korth, J.; Kuzuhara, Masayuki; Lafarga, M.; Lampón, M.; Leão, I. C.; Livingston, John H.; Mathur, S.; Montañés-Rodŕıguez, P.; Morales, J. C.; Murgas, F.; Nagel, E.; Narita, Norio; Nielsen, L. D.; Pätzold, M.; Persson, C. M.; Quirrenbach, A.; Rauer, H.; Redfield, Seth; Reiners, A.; Ribas, I.; Smith, A. M. S.; Šubjak, J.; Eylen, Vincent Van; Wilson, Paul

doi:10.1051/0004-6361/201937080

Cited by 15 publications

(7 citation statements)

References 89 publications

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“…More detail for each of these planets is discussed below. (Hidalgo et al 2020). This small discrepancy is also found with its exoplanetary siblings K2-314 c and K2-314 d, found in Figure 6.…”

Section: Our Resultssupporting

confidence: 70%

The GALAH Survey: Improving our understanding of confirmed and candidate planetary systems with large stellar surveys

Clark,

Wright,

Wittenmyer

et al. 2021

Preprint

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Pioneering photometric, astrometric, and spectroscopic surveys are helping exoplanetary scientists better constrain the fundamental properties of stars within our galaxy, and the planets these stars host. In this study, we use the third data release from the stellar spectroscopic GALAH Survey, coupled with astrometric data of eDR3 from the Gaia satellite, and other data from NASA's Exoplanet Archive, to refine our understanding of 279 confirmed and candidate exoplanet host stars and their exoplanets. This homogenously analysed data set comprises 105 confirmed exoplanets, along with 146 K2 candidates, 95 TESS Objects of Interest (TOIs) and 52 Community TOIs (CTOIs). Our analysis significantly shifts several previously (unknown) planet parameters while decreasing the uncertainties for others; Our radius estimates suggest that 35 planet candidates are more likely brown dwarfs or stellar companions due to their new radius values. We are able to refine the radii and masses of WASP-47 e, K2-106 b, and CoRoT-7 b to their most precise values yet, to less than 2.3% and 8.5% respectively. We also use stellar rotational values from GALAH to show that most planet candidates will have mass measurements that will be tough to obtain with current ground-based spectrographs. With GALAH's chemical abundances, we show through chemo-kinematics that there are five planet-hosts that are associated with the galaxy's thick disc, including NGTS-4, K2-183 and K2-337. Finally, we show there is no statistical difference between the chemical properties of hot Neptune and hot rocky exoplanet hosts, with the possibility that short-period rocky worlds might be the remnant cores of hotter, gaseous worlds.

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Section: Our Resultssupporting

confidence: 70%

The GALAH Survey: Improving our understanding of confirmed and candidate planetary systems with large stellar surveys

Clark,

Wright,

Wittenmyer

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

Section: Fundamental Properties Of Our Ultra Short-period Exoplanet S...mentioning

confidence: 99%

“…(i) K2-314 b: K2-314 b, also known as EPIC 249893012 b, is a super-Earth-sized exoplanet first disco v ered in 2020 by Hidalgo et al ( 2020 ) orbiting a slightly evolved, metal-rich ([Fe/H] = 0.19) G-type star. Our stellar parameters for K2-314, 1.71 ± 0.03 R , and 1.07 ± 0.03 M , compared to those found in Hidalgo et al ( 2020 ), 1.71 ± 0.04 R and 1.05 ± 0.05 M , are almost identical with only a very slight adjustment to the star's mass values. This small discrepancy in stellar values translates to an insignificant change in the exoplanet's mass and radius values, with our values of 1.94 ± 0.09R ⊕ and 8.89 ± 1.12M ⊕ for K2-314 b, compared to its original values of 1.95 + 0 .…”

Section: Fundamental Properties Of Our Ultra Short-period Exoplanet S...mentioning

confidence: 99%

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The GALAH Survey: improving our understanding of confirmed and candidate planetary systems with large stellar surveys

Clark

Wright

Wittenmyer

et al. 2021

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Pioneering photometric, astrometric, and spectroscopic surveys are helping exoplanetary scientists better constrain the fundamental properties of stars within our galaxy, and the planets these stars host. In this study, we use the third data release from the stellar spectroscopic GALAH Survey, coupled with astrometric data of eDR3 from the Gaia satellite, and other data from NASA’s Exoplanet Archive, to refine our understanding of 279 confirmed and candidate exoplanet host stars and their exoplanets. This homogenously analysed data set comprises 105 confirmed exoplanets, along with 146 K2 candidates, 95 TESS Objects of Interest (TOIs) and 52 Community TOIs (CTOIs). Our analysis significantly shifts several previously (unknown) planet parameters while decreasing the uncertainties for others; Our radius estimates suggest that 35 planet candidates are more likely brown dwarfs or stellar companions due to their new radius values. We are able to refine the radii and masses of WASP-47 e, K2-106 b, and CoRoT-7 b to their most precise values yet, to less than 2.3% and 8.5% respectively. We also use stellar rotational values from GALAH to show that most planet candidates will have mass measurements that will be tough to obtain with current ground-based spectrographs. With GALAH’s chemical abundances, we show through chemo-kinematics that there are five planet-hosts that are associated with the galaxy’s thick disc, including NGTS-4, K2-183 and K2-337. Finally, we show there is no statistical difference between the chemical properties of hot Neptune and hot rocky exoplanet hosts, with the possibility that short-period rocky worlds might be the remnant cores of hotter, gaseous worlds.

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“…Another eight planets were found around earlier-type stars (Luque et al 2019a;Palle et al 2019;Hidalgo et al 2020). In addition to finding planets, CARMENES has been used to derive stellar parameters (e.g.…”

Section: Carmenesmentioning

confidence: 99%

Activity of M dwarfs in the CARMENES sample

Schöfer¹

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The Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs (CARMENES) has been searching and finding planets for five years by looking for periodic Doppler-shift variations down to 1 m s −1 . One challenge in detecting planetary signals with this precision is that activity phenomena on the star can mimic Doppler signals in the same order of magnitude. While stellar activity imposes this challenge for finding planets, the spectra obtained in the survey also provide a treasury of data for studying stellar activity itself. In this thesis, I aim to quantify the stellar activity of 337 M dwarfs in the CARMENES sample by measuring the strength of chromospheric emission lines and photospheric absorption bands, to identify correlations, and to investigate the temporal variability of the activity indicators. I used a spectral subtraction technique to measure pseudo-equivalent widths of the He i D 3 , Hα, He i λ10833 Å, and Paβ lines, the Na i D doublet, and the Ca ii infrared triplet. For three TiO, two CaH, and two VO absorption bands and the FeH Wing-Ford band, I calculated indices as the flux ratio of two spectral regions on either side of the band heads. Using generalised Lomb-Scargle periodograms, I searched for periodicities in the measured indicators. I analysed four out of eighteen stars that show a periodic modulation with the rotation period in more than two indicators in more detail. I find that He i D 3 and Hα show a very similar spectral-type dependence and are strongly correlated. For Na i D and the Ca ii infrared triplet, the correlation with Hα is weaker, as the subtraction method cannot adjust for the very different shapes of these lines. No strong correlations with the other indicators are found for He i λ10833 Å and Paβ. The photospheric bands are strongly correlated with each other and show activity effects of different intensities. I outline a new indicator to quantify these effects. All results are in good agreement with previously published results. He i D 3 and Hα show smaller relative variations at higher activity levels, whereas the relative variations of other indicators show no clear correlations. One TiO band, one CaH band, one line of the Ca ii infrared triplet, and Hα undergo periodic modulations with the rotation period most commonly. The more detailed analysis of four stars shows the peculiarities in the signals of each star and reveals changing signals over time. Luminosity classesScatter plots of the classification by apparent brightness and the classification by colour, temperature, or spectral type, are called colour-magnitude diagrams. Using the absolute Logarithmic probabilities more negative than −2.87 indicate a significance higher than 3σ and are highlighted in boldface.

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Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M_⊕ super-Earth and two warm 14.7 and 10.2-M_⊕ sub-Neptunes

Cited by 15 publications

References 89 publications

The GALAH Survey: Improving our understanding of confirmed and candidate planetary systems with large stellar surveys

The GALAH Survey: Improving our understanding of confirmed and candidate planetary systems with large stellar surveys

The GALAH Survey: improving our understanding of confirmed and candidate planetary systems with large stellar surveys

Activity of M dwarfs in the CARMENES sample

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