scholarly journals X-ray irradiation and evaporation of the four young planets around V1298 Tau

2020 ◽  
Vol 500 (4) ◽  
pp. 4560-4572
Author(s):  
K Poppenhaeger ◽  
L Ketzer ◽  
M Mallonn
Keyword(s):  
Mass Loss ◽  
High Energy ◽  
Magnetic Activity ◽  
Young Star ◽  
Young Stars ◽  
X Ray ◽  
Energy Irradiation ◽  
Irradiation Level ◽  
Host Stars ◽  
Gaseous Envelopes

ABSTRACT Planets around young stars are thought to undergo atmospheric evaporation due to the high magnetic activity of the host stars. Here we report on X-ray observations of V1298 Tau, a young star with four transiting exoplanets. We use X-ray observations of the host star with Chandra and ROSAT to measure the current high-energy irradiation level of the planets and employ a model for the stellar activity evolution together with exoplanetary mass-loss to estimate the possible evolution of the planets. We find that V1298 Tau is X-ray bright with log LX [erg s−1] = 30.1 and has a mean coronal temperature of ≈9 MK. This places the star amongst the more X-ray luminous ones at this stellar age. We estimate the radiation-driven mass-loss of the exoplanets and find that it depends sensitively on the possible evolutionary spin-down tracks of the star as well as on the current planetary densities. Assuming the planets are of low density due to their youth, we find that the innermost two planets can lose significant parts of their gaseous envelopes and could be evaporated down to their rocky cores depending on the stellar spin evolution. However, if the planets are heavier and follow the mass–radius relation of older planets, then even in the highest XUV irradiation scenario none of the planets is expected to cross the radius gap into the rocky regime until the system reaches an age of 5 Gyr.

scholarly journals Mass loss from the exoplanet WASP-12b inferred from Spitzer phase curves

2019 ◽  
Vol 489 (2) ◽  
pp. 1995-2013 ◽  
Author(s):  
Taylor J Bell ◽  
Michael Zhang ◽  
Patricio E Cubillos ◽  
Lisa Dang ◽  
Luca Fossati ◽  
...  
Keyword(s):  
Mass Loss ◽  
Infrared Radiation ◽  
High Energy ◽  
The Other ◽  
Phase Curve ◽  
Near Ultraviolet ◽  
Energy Irradiation ◽  
Ultraviolet Observations ◽  
Host Stars ◽  
Co Emission

ABSTRACT The exoplanet WASP-12b is the prototype for the emerging class of ultrahot, Jupiter-mass exoplanets. Past models have predicted – and near-ultraviolet observations have shown – that this planet is losing mass. We present an analysis of two sets of 3.6 and 4.5 $\mu \rm{m}$Spitzer phase curve observations of the system which show clear evidence of infrared radiation from gas stripped from the planet, and the gas appears to be flowing directly toward or away from the host star. This accretion signature is only seen at 4.5 $\mu \rm{m}$, not at 3.6 $\mu \rm{m}$, which is indicative either of CO emission at the longer wavelength or blackbody emission from cool, ≲600 K gas. It is unclear why WASP-12b is the only ultrahot Jupiter to exhibit this mass-loss signature, but perhaps WASP-12b’s orbit is decaying as some have claimed, while the orbits of other exoplanets may be more stable; alternatively, the high-energy irradiation from WASP-12A may be stronger than the other host stars. We also find evidence for phase offset variability at the level of 6.4σ (46.2°) at 3.6 $\mu \rm{m}$.

scholarly journals X-ray emission in the enigmatic CVSO 30 system

2019 ◽  
Vol 629 ◽  
pp. A5 ◽  
Author(s):  
S. Czesla ◽  
P. C. Schneider ◽  
M. Salz ◽  
T. Klocová ◽  
T. O. B. Schmidt ◽  
...  
Keyword(s):  
Mass Loss ◽  
Planetary System ◽  
High Energy ◽  
Weak Line ◽  
Coronal Emission ◽  
Interstellar Absorption ◽  
X Ray ◽  
T Tauri ◽  
Energy Irradiation ◽  
Hot Jupiter

CVSO 30 is a young, active, weak-line T Tauri star; it possibly hosts the only known planetary system with both a transiting hot-Jupiter and a cold-Jupiter candidate (CVSO 30 b and CVSO 30 c). We analyzed archival ROSAT, Chandra, and XMM-Newton data to study the coronal emission in the system. According to our modeling, CVSO 30 shows a quiescent X-ray luminosity of ≈8 × 1029 erg s−1. The X-ray absorbing column is consistent with interstellar absorption. XMM-Newton observed a flare, during which a transit of the candidate CVSO 30 b was expected, but no significant transit-induced variation in the X-ray flux is detectable. While the hot-Jupiter candidate CVSO 30 b has continuously been undergoing mass loss powered by the high-energy irradiation, we conclude that its evaporation lifetime is considerably longer than the estimated stellar age of 2.6 Myr.

scholarly journals Constraining X-ray-Induced Photoevaporation of Protoplanetary Disks Orbiting Low-Mass Stars

2015 ◽  
Vol 10 (S314) ◽  
pp. 203-204
Author(s):  
Kristina M. Punzi ◽  
Joel H. Kastner ◽  
David Rodriguez ◽  
David A. Principe ◽  
Laura Vican
Keyword(s):  
Protoplanetary Disks ◽  
High Energy ◽  
Magnetic Activity ◽  
Young Star ◽  
Low Mass Stars ◽  
High Energy Radiation ◽  
X Ray ◽  
Radiation Fields ◽  
Low Mass ◽  
M Stars

AbstractLow-mass, pre-main sequence stars possess intense high-energy radiation fields as a result of their strong stellar magnetic activity. This stellar UV and X-ray radiation may have a profound impact on the lifetimes of protoplanetary disks. We aim to constrain the X-ray-induced photoevaporation rates of protoplanetary disks orbiting low-mass stars by analyzing serendipitous XMM-Newton and Chandra X-ray observations of candidate nearby (D < 100 pc), young (age < 100 Myr) M stars identified in the GALEX Nearby Young-Star Survey (GALNYSS).

Implications of stellar activity for exoplanetary atmospheres

2010 ◽  
Vol 9 (4) ◽  
pp. 239-243 ◽  
Author(s):  
P. Odert ◽  
M. Leitzinger ◽  
A. Hanslmeier ◽  
H. Lammer ◽  
M.L. Khodachenko ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Planetary Atmospheres ◽  
Young Star ◽  
Young Stars ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
X Ray ◽  
History Of ◽  
Low Mass ◽  
Exoplanetary Atmospheres

AbstractStellar X-ray and extreme ultraviolet (XUV) radiation is an important driver of the escape of planetary atmospheres. Young stars emit high XUV fluxes that decrease as they age. Since the XUV emission of a young star can be orders of magnitude higher compared to an older one, this evolution has to be taken into account when studying the mass-loss history of a planet. The temporal decrease of activity is closely related to the operating magnetic dynamo, which depends on rotation and convection in Sun-like stars. Using a sample of nearby M dwarfs, we study the relations between age, rotation and activity and discuss the influence on planets orbiting these low-mass stars.

scholarly journals Non thermal emission from T Tauri stars

2010 ◽  
Vol 6 (S275) ◽  
pp. 404-405
Author(s):  
María V. del Valle ◽  
Gustavo E. Romero
Keyword(s):  
Main Sequence ◽  
Thermal Emission ◽  
High Energy ◽  
Magnetic Activity ◽  
T Tauri Stars ◽  
Main Sequence Stars ◽  
High Energy Radiation ◽  
X Ray ◽  
T Tauri ◽  
Low Mass

AbstractT Tauri stars are low mass, pre-main sequence stars. These objects are surrounded by an accretion disk and present strong magnetic activity. T Tauri stars are copious emitters of X-ray emission which belong to powerful magnetic reconnection events. Strong magnetospheric shocks are likely outcome of massive reconnection. Such shocks can accelerate particles up to relativistic energies through Fermi mechanism. We present a model for the high-energy radiation produced in the environment of T Tauri stars. We aim at determining whether this emission is detectable. If so, the T Tauri stars should be very nearby.

scholarly journals The Sun in time: age, rotation, and magnetic activity of the Sun and solar-type stars and effects on hosted planets

2008 ◽  
Vol 4 (S258) ◽  
pp. 395-408 ◽  
Author(s):  
Edward F. Guinan ◽  
Scott G. Engle
Keyword(s):  
Main Sequence ◽  
High Energy ◽  
Magnetic Activity ◽  
The Sun ◽  
X Ray ◽  
Multi Wavelength ◽  
Solar Type ◽  
Rotation Age ◽  
Energy Emissions ◽  
Solar Analogs

AbstractMulti-wavelength studies of solar analogs (G0–5 V stars) with ages from ~50 Myr to 9 Gyr have been carried out as part of the “Sun in Time” program for nearly 20 yrs. From these studies it is inferred that the young (ZAMS) Sun was rotating more than 10× faster than today. As a consequence, young solar-type stars and the early Sun have vigorous magnetohydrodynamic (MHD) dynamos and correspondingly strong coronal X-ray and transition region/chromospheric FUV–UV emissions (up to several hundred times stronger than the present Sun). Also, rotational modulated, low amplitude light variations of young solar analogs indicate the presence of large starspot regions covering ~5–30% of their surfaces. To ensure continuity and homogeneity for this program, we use a restricted sample of G0–5 V stars with masses, radii, Teff, and internal structure (i.e. outer convective zones) closely matching those of the Sun. From these analogs we have determined reliable rotation-age-activity relations and X-ray–UV (XUV) spectral irradiances for the Sun (or any solar-type star) over time. These XUV irradiance measures serve as input data for investigating the photo-ionization and photo-chemical effects of the young, active Sun on the paleo-planetary atmospheres and environments of solar system planets. These measures are also important to study the effects of these high energy emissions on the numerous exoplanets hosted by solar-type stars of different ages. Recently we have extended the study to include lower mass, main-sequence (dwarf) dK and dM stars to determine relationships among their rotation spin-down rates and coronal and chromospheric emissions as a function of mass and age. From rotation-age-activity relations we can determine reliable ages for main-sequence G, K, M field stars and, subsequently, their hosted planets. Also inferred are the present and the past XUV irradiance and plasma flux exposures that these planets have endured and the suitability of the hosted planets to develop and sustain life.

scholarly journals Ultraviolet and X-ray irradiance and flares from low-mass exoplanet host stars

2015 ◽  
Vol 11 (S320) ◽  
pp. 370-375
Author(s):  
Kevin France ◽  
R. O. Parke Loyd ◽  
Alex Brown
Keyword(s):  
Hubble Space Telescope ◽  
Planetary Systems ◽  
High Energy ◽  
Time Variability ◽  
M Dwarfs ◽  
X Ray ◽  
Uv Emission ◽  
Potential Biomarker ◽  
Low Mass ◽  
Host Stars

AbstractThe spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. High-energy photons (X-ray to NUV) from these stars regulate the atmospheric temperature profiles and photochemistry on orbiting planets, influencing the production of potential “biomarker” gases. We report first results from the MUSCLES Treasury Survey, a study of time-resolved UV and X-ray spectroscopy of nearby M and K dwarf exoplanet host stars. This program uses contemporaneous Hubble Space Telescope and Chandra (or XMM) observations to characterize the time variability of the energetic radiation field incident on the habitable zones planetary systems at d ≲ 20 pc. We find that all exoplanet host stars observed to date exhibit significant levels of chromospheric and transition region UV emission. M dwarf exoplanet host stars display 30–7000% UV emission line amplitude variations on timescales of minutes-to-hours. The relative flare/quiescent UV flux amplitudes on weakly active planet-hosting M dwarfs are comparable to active flare stars (e.g., AD Leo), despite their weak optical activity indices (e.g., Ca II H and K equivalent widths). We also detect similar UV flare behavior on a subset of our K dwarf exoplanet host stars. We conclude that strong flares and stochastic variability are common, even on “optically inactive” M dwarfs hosting planetary systems. These results argue that the traditional assumption of weak UV fields and low flare rates on older low-mass stars needs to be revised.

scholarly journals Bright Young Star Candidates in the Rosette Nebula

2001 ◽  
Vol 183 ◽  
pp. 335-336
Author(s):  
P.S. Chiang ◽  
W.P. Chen ◽  
J.Z. Li ◽  
Y.-H. Chu
Keyword(s):  
Young Star ◽  
Point Sources ◽  
Young Stars ◽  
X Ray ◽  
Rosette Nebula ◽  
X Ray Background

AbstractWe identified possible optical young stars in the Rosette Nebula by using the IRAS and the ROSAT databases. The previously reported “diffuse” X-ray emission has been resolved into point sources. Forty-seven point sources are detected above 3-sigma of the X-ray background, and twenty-seven of these have stellar counterparts. Some of the young star candidates appear to be associated Herbig-Haro nebular features.

scholarly journals High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood

2015 ◽  
Vol 576 ◽  
pp. A42 ◽  
Author(s):  
M. Salz ◽  
P. C. Schneider ◽  
S. Czesla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Mass Loss ◽  
High Energy ◽  
Solar Neighborhood ◽  
Hot Jupiters ◽  
Energy Irradiation ◽  
High Energy Irradiation ◽  
Loss Rates

scholarly journals Detailed characterization of stellar high energy (FUV/EUV/X-ray) radiation fields during protoplanetary system formation

2009 ◽  
Vol 5 (S264) ◽  
pp. 395-400 ◽  
Author(s):  
Alexander Brown
Keyword(s):  
Main Sequence ◽  
Thermal Structure ◽  
High Energy ◽  
Young Stars ◽  
The Sun ◽  
Nearby Star ◽  
Stellar Activity ◽  
Local Association ◽  
X Ray ◽  
Radiation Fields

AbstractYoung stars undergoing the conversion of pre-main-sequence circumstellar disks into protoplanetary systems are strong sources of high energy (FUV/EUV/X-ray) radiation that controls the physical and chemical processes in their circumstellar environment out to hundreds of AU from the star. The high energy radiation resulting from magnetic activity and accretion onto the central star controls the thermal structure of disks, the formation process of planetesimals, and the photoexcitation and photoionization of protoplanets and young planetary atmospheres. Modeling of the dust and gas evolution requires an accurate understanding of the local radiation field throughout the ultraviolet (UV) and X-ray spectral regions, even those parts of the spectrum that are impossible to observe from Earth.Our current research efforts are directed towards developing a better understanding of UV (using HST and FUSE) and X-ray (using Chandra, XMM-Newton, and Swift) stellar activity and the resulting radiation fields during pre-main-sequence evolution from ages of a few to several hundred million years. These studies include extensive UV and X-ray spectral sampling of individual stars in nearby star formation regions and the various moving groups of the Local Association, including our HST Cycle 17 Large Project (GO-11616), which is using 111 HST orbits to observe 32 T Tauri stars with the COS UV spectrograph. Most young stars are well over 100 pc from the Sun and are consequently hard to observe in the UV and X-ray regions at even moderate spectral resolution. However, members of the Local Association, whose ages range from 7 Myr to a few hundred Myr, surround the Sun at distances of 50 pc or less and permit the detailed study of the later stages of the early evolution of stellar activity when gas giant and terrestrial protoplanets are forming. We illustrate our methodology using the 12 Myr old early-M dwarf AU Mic, which possesses a striking dust debris disk, as an example.

Sign in / Sign up

Export Citation Format

Share Document