scholarly journals Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

2019 ◽  
Vol 878 (1) ◽  
pp. 7
Author(s):  
Huan Y. A. Meng ◽  
G. H. Rieke ◽  
Jinyoung Serena Kim ◽  
Aurora Sicilia-Aguilar ◽  
N. J. G. Cross ◽  
...  
Geosciences ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 289 ◽  
Author(s):  
Serena Benatti

Exoplanet research has shown an incessant growth since the first claim of a hot giant planet around a solar-like star in the mid-1990s. Today, the new facilities are working to spot the first habitable rocky planets around low-mass stars as a forerunner for the detection of the long-awaited Sun-Earth analog system. All the achievements in this field would not have been possible without the constant development of the technology and of new methods to detect more and more challenging planets. After the consolidation of a top-level instrumentation for high-resolution spectroscopy in the visible wavelength range, a huge effort is now dedicated to reaching the same precision and accuracy in the near-infrared. Actually, observations in this range present several advantages in the search for exoplanets around M dwarfs, known to be the most favorable targets to detect possible habitable planets. They are also characterized by intense stellar activity, which hampers planet detection, but its impact on the radial velocity modulation is mitigated in the infrared. Simultaneous observations in the visible and near-infrared ranges appear to be an even more powerful technique since they provide combined and complementary information, also useful for many other exoplanetary science cases.


2008 ◽  
Vol 136 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Juan José Downes ◽  
César Briceño ◽  
Jesús Hernández ◽  
Nuria Calvet ◽  
Lee Hartmann ◽  
...  

2009 ◽  
Author(s):  
Emily L. Rice ◽  
Travis S. Barman ◽  
Ian S. McLean ◽  
L. Prato ◽  
J. Davy Kirkpatrick ◽  
...  

2003 ◽  
Vol 211 ◽  
pp. 413-416 ◽  
Author(s):  
D. Ségransan ◽  
X. Delfosse ◽  
T. Forveille ◽  
J.L. Beuzit ◽  
C. Perrier ◽  
...  

We present new accurate masses at the bottom of the main sequence as well as an improved empirical mass-luminosity relation for very low mass stars in the visible and near infrared. Masses were obtained by combining very accurate radial velocities and adaptive optics images of multiple stars obtained at different orbital phases.


2016 ◽  
Vol 128 (968) ◽  
pp. 104501 ◽  
Author(s):  
Peter Gao ◽  
Plavchan P. ◽  
Gagné J. ◽  
Furlan E. ◽  
Bottom M. ◽  
...  

1998 ◽  
Vol 11 (1) ◽  
pp. 136-136
Author(s):  
Hans Zinnecker

Abstract Diffraction limited near-infrared H-band (1.6 μm) NICMOS HST images are scheduled to be obtained in mid-October 1997 of the young cluster NGC 2070 (age 3.5 Myr) in the 30 Dor giant HII region in the LMC. The aim is to search for the low-mass (M < 2 Mʘ) low-luminosity, red pre-Main Sequence stellar population and to establish the H-band infrared luminosity function. With the NICMOS we can now determine whether the IMF in this prototypical extragalactic starburst cluster is deficient in subsolar low-mass stars or not. The best ground-based data can sample only M > 2 Mʘ. In principle, NICMOS in the H-band (F160W) is sensitive enough to reach a magnitude of ~ 23.5 in a relatively short integration time, which indeed corresponds to the fantastic possibility to detect young stellar objects with masses near the hydrogen burning limit (M=0.1 Mʘ) according to pre-Main Sequence evolutionary models. Even if we could reach only H = 22.5 (i.e. M=0.4 Mʘ), our observations will still go a long way in directly answering, by star counts, whether the IMF in starburst galaxies is low-mass deficient or not, with all the corresponding far-reaching implications. The observations would also tell us whether the 30 Dor cluster can be regarded as a prototype young globular cluster. This possibility would be ruled out, if we found NGC 2070 to be low-mass deficient, because old globular clusters do have a rich population of low-mass stars.


2002 ◽  
Vol 207 ◽  
pp. 378-382 ◽  
Author(s):  
Sabine Mengel ◽  
Matthew D. Lehnert ◽  
Niranjan Thatte ◽  
Reinhard Genzel

Over the past decade, it has become clear that interaction induced formation of compact young star clusters is a ubiquitous pheonomenon, and the understanding of this process is thought to also shed light on galaxy evolution in general, because these young clusters are widely believed to be the progenitors of a part of the globular cluster systems seen in local elliptical galaxies. We have observed the prototypical merger NGC 4038/4039 using near-infrared broad- and narrow band imaging, integral field spectroscopy and medium and high resolution spectroscopy. We find that all of the bright star clusters are young (<20 Myrs), but the “overlap region” hosts the youngest clusters (∼5 Myrs), while the nuclear starbursts started ∼100 Myrs ago. Photometric and dynamical masses range from 105 to a few x106M⊙. However, mass-to-light ratios vary from cluster to cluster and suggest differences in the contribution of low-mass stars. While clusters with a deficiency in low-mass stars are likely to evaporate before they are a Hubble time old, those with a high mass-to-light-ratio could represent young globulars.


1995 ◽  
Vol 148 ◽  
pp. 376-379
Author(s):  
Makoto Nakano ◽  
Peter J. McGregor

AbstractNear-infrared photometry is reported for 76 emission-line stars in outer regions of the Orion molecular cloud complex. Most of our program stars are selected from the Hα emission-line star catalog of the large-scale Kiso Schmidt survey of the Orion region. We confirm that most of the emission-line stars with strong emission detected in the Kiso survey are typical T Tauri stars with masses in the range 0.5 to 2 M⊙. Low mass stars have therefore continued to form in the outer parts of the Orion region, away from present day massive molecular clouds, until at least as recently as a few million year ago.


1991 ◽  
Vol 147 ◽  
pp. 345-352
Author(s):  
S. Terebey ◽  
C. A. Beichman ◽  
T. N. Gautier ◽  
J. J. Hester ◽  
P. C. Myers ◽  
...  

We present results from a near-infrared array, CO interferometer, and H2O maser interferometer survey of the circumstellar environments of 26 young low-luminosity embedded stars located in nearby molecular clouds. About 75% of the sample show evidence for stellar winds/outflows in the near-infrared or CO data indicating that most of these sources are in the early wind clearing phase of their evolution. Close to 15% are multiple on the scale of 20″, suggesting that fragmentation of their surrounding dense cloud cores is important before or during gravitational collapse. Roughly 10% have H2O maser emission and the kinematics imply the masers arise in gravitationally unbound gas (i.e., a stellar wind or outflow) rather than in a circumstellar disk.


2008 ◽  
Vol 4 (S253) ◽  
pp. 157-161 ◽  
Author(s):  
James P. Lloyd ◽  
Agnieszka Czeszumska ◽  
Jerry Edelstein ◽  
David Erskine ◽  
Michael Feuerstein ◽  
...  

AbstractThe TEDI (TripleSpec - Exoplanet Discovery Instrument) is a dedicated instrument for the near-infrared radial velocity search for planetary companions to low-mass stars with the goal of achieving meters-per-second radial velocity precision. Heretofore, such planet searches have been limited almost entirely to the optical band and to stars that are bright in this band. Consequently, knowledge about planetary companions to the populous but visibly faint low-mass stars is limited. In addition to the opportunity afforded by precision radial velocity searches directly for planets around low mass stars, transits around the smallest M dwarfs offer a chance to detect the smallest possible planets in the habitable zones of the parent stars. As has been the the case with followup of planet candidates detected by the transit method requiring radial velocity confirmation, the capability to undertake efficient precision radial velocity measurements of mid-late M dwarfs will be required. TEDI has been commissioned on the Palomar 200” telescope in December 2007, and is currently in a science verification phase.


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